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| m68hc08m68h c08m68hc08m 68hc08m68hc mc68hc 08 az 32a tec hnical data hcmos microcontroller unit mc68hc 0 8 az 32 a / d rev 1. 0
MC68HC08AZ32A ? rev 1.0 technical data motorola 3 MC68HC08AZ32A technical data ? rev 1.0 motorola reserves the right to make changes without further notice to any products herein. motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. "typical" parameters which may be provided in motorola data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. all operating parameters, including "typicals" must be validated for each customer application by customer?s technical experts. motorola does not convey any license under its patent rights nor the rights of others. motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the motorola product could create a situation where personal injury or death may occur. should buyer purchase or use motorola products for any such unintended or unauthorized application, buyer shall indemnify and hold motorola and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that motorola was negligent regarding the design or manufacture of the part. motorola, inc. is an equal opportunity/affirmative action employer. motorola and are registered trademarks of motorola, inc. digitaldna is a trademark of motorola, inc. ? motorola, inc., 2001 technical data MC68HC08AZ32A ? rev 1.0 4 motorola MC68HC08AZ32A ? rev 1.0 technical data motorola list of paragraphs 5 technical data ? MC68HC08AZ32A list of paragraphs list of paragraphs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 table of contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 list of figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 list of tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 section 1. general description . . . . . . . . . . . . . . . . . . . . 27 section 2. memory map . . . . . . . . . . . . . . . . . . . . . . . . . . 41 section 3. ram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 section 4. rom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 section 5. eeprom. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 section 6. central processor unit (cpu) . . . . . . . . . . . . 77 section 7. system integration module (sim) . . . . . . . . . 95 section 8. clock generator module (cgm) . . . . . . . . . . 117 section 9. mask options. . . . . . . . . . . . . . . . . . . . . . . . . 145 section 10. break module. . . . . . . . . . . . . . . . . . . . . . . . 149 section 11. monitor rom (mon) . . . . . . . . . . . . . . . . . . 155 section 12. computer operating properly (cop) . . . . 167 section 13. low voltage inhibit (lvi) . . . . . . . . . . . . . . 173 section 14. external interrupt module (irq) . . . . . . . . . 179 section 15. serial communications interface (sci) . . . 187 section 16. serial peripheral interface (spi). . . . . . . . . 227 list of paragraphs technical data MC68HC08AZ32A ? rev 1.0 6 list of paragraphs motorola section 17. timer interface module b (timb) . . . . . . . . 259 section 18. programmable interrupt timer (pit) . . . . . 283 section 19. i/o ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 section 20. mscan08 controller (mscan08) . . . . . . . 321 section 21. keyboard module (kbd) . . . . . . . . . . . . . . . 373 section 22. timer interface module a (tima) . . . . . . . . 381 section 23. analog-to-digital converter (adc-15) . . . . 411 section 24. electrical specifications. . . . . . . . . . . . . . . 423 section 25. MC68HC08AZ32A changes . . . . . . . . . . . . 437 revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443 glossary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445 MC68HC08AZ32A ? rev 1.0 technical data motorola table of contents 7 technical data ? MC68HC08AZ32A table of contents list of paragraphs table of contents list of figures list of tables section 1. general description 1.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 1.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 1.4 pin assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1.5 ordering information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 section 2. memory map 2.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 2.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 2.3 i/o section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 2.4 additional status and control registers . . . . . . . . . . . . . . . . . . 49 2.5 vector addresses and priority . . . . . . . . . . . . . . . . . . . . . . . . . 50 table of contents technical data MC68HC08AZ32A ? rev 1.0 8 table of contents motorola section 3. ram 3.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53 3.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3.3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 section 4. rom 4.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 4.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.4 security. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 section 5. eeprom 5.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57 5.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58 5.4 eeprom register summary . . . . . . . . . . . . . . . . . . . . . . . . . . 59 5.5 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 5.6 eeprom register descriptions . . . . . . . . . . . . . . . . . . . . . . . . 67 5.7 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 section 6. central processor unit (cpu) 6.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77 6.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 6.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78 6.4 cpu registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 6.5 arithmetic/logic unit (alu) . . . . . . . . . . . . . . . . . . . . . . . . . . .83 6.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84 table of contents MC68HC08AZ32A ? rev 1.0 technical data motorola table of contents 9 6.7 cpu during break interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . 84 6.8 instruction set summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 6.9 opcode map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 section 7. system integration module (sim) 7.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95 7.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 7.3 sim bus clock control and generation . . . . . . . . . . . . . . . . . . 98 7.4 reset and system initialization. . . . . . . . . . . . . . . . . . . . . . . . . 99 7.5 sim counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104 7.6 exception control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 7.7 break interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108 7.8 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109 7.9 sim registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 section 8. clock generator module (cgm) 8.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117 8.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 8.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118 8.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 8.5 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 8.6 cgm registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .131 8.7 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137 8.8 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137 8.9 cgm during break interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 138 8.10 acquisition/lock time specifications . . . . . . . . . . . . . . . . . . .138 table of contents technical data MC68HC08AZ32A ? rev 1.0 10 table of contents motorola section 9. mask options 9.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .145 9.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 9.3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 section 10. break module 10.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 10.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 10.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 10.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 10.5 break module registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . .152 10.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .154 section 11. monitor rom (mon) 11.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 11.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 11.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 11.4 functional description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 section 12. computer operating properly (cop) 12.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 12.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 12.3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 12.4 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 12.5 cop control register (copctl) . . . . . . . . . . . . . . . . . . . . . .171 12.6 interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 12.7 monitor mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 table of contents MC68HC08AZ32A ? rev 1.0 technical data motorola table of contents 11 12.8 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171 12.9 cop module during break interrupts . . . . . . . . . . . . . . . . . . . 172 section 13. low voltage inhibit (lvi) 13.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 13.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 13.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 13.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 13.5 lvi status register (lvisr) . . . . . . . . . . . . . . . . . . . . . . . . . . 176 13.6 lvi interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 13.7 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .177 section 14. external interrupt module (irq) 14.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 14.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 14.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 14.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 14.5 irq module during break interrupts . . . . . . . . . . . . . . . . . . .184 14.6 irq status and control register (iscr) . . . . . . . . . . . . . . . . 184 section 15. serial communications interface (sci) 15.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 15.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 15.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 15.4 pin name conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 15.5 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 15.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .207 table of contents technical data MC68HC08AZ32A ? rev 1.0 12 table of contents motorola 15.7 sci during break module interrupts. . . . . . . . . . . . . . . . . . . . 208 15.8 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 15.9 i/o registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 section 16. serial peripheral interface (spi) 16.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227 16.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228 16.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228 16.4 pin name conventions and i/o register addresses . . . . . . . 229 16.5 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230 16.6 transmission formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234 16.7 interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 16.8 queuing transmission data . . . . . . . . . . . . . . . . . . . . . . . . . . 244 16.9 resetting the spi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246 16.10 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .247 16.11 spi during break interrupts . . . . . . . . . . . . . . . . . . . . . . . . . .247 16.12 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248 16.13 i/o registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 section 17. timer interface module b (timb) 17.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259 17.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260 17.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260 17.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262 17.5 interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 17.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .270 17.7 timb during break interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 271 table of contents MC68HC08AZ32A ? rev 1.0 technical data motorola table of contents 13 17.8 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 17.9 i/o registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272 section 18. programmable interrupt timer (pit) 18.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283 18.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283 18.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284 18.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284 18.5 pit counter prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285 18.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .286 18.7 pit during break interrupts . . . . . . . . . . . . . . . . . . . . . . . . . .286 18.8 i/o registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287 section 19. i/o ports 19.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 19.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294 19.3 port a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 19.4 port b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 19.5 port c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 19.6 port d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304 19.7 port e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307 19.8 port f . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312 19.9 port g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .315 19.10 port h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318 table of contents technical data MC68HC08AZ32A ? rev 1.0 14 table of contents motorola section 20. mscan08 controller (mscan08) 20.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321 20.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322 20.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 20.4 external pins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324 20.5 message storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .325 20.6 identifier acceptance filter . . . . . . . . . . . . . . . . . . . . . . . . . . . 330 20.7 interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335 20.8 protocol violation protection. . . . . . . . . . . . . . . . . . . . . . . . . . 337 20.9 low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .338 20.10 timer link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342 20.11 clock system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342 20.12 memory map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346 20.13 programmer ? s model of message storage . . . . . . . . . . . . . . .346 20.14 programmer ? s model of control registers . . . . . . . . . . . . . . . 352 section 21. keyboard module (kbd) 21.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373 21.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373 21.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 21.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 21.5 keyboard initialization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377 21.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .378 21.7 keyboard module during break interrupts . . . . . . . . . . . . . . .378 21.8 i/o registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379 table of contents MC68HC08AZ32A ? rev 1.0 technical data motorola table of contents 15 section 22. timer interface module a (tima) 22.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381 22.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382 22.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382 22.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385 22.5 interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395 22.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .395 22.7 tima during break interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 396 22.8 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396 22.9 i/o registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397 section 23. analog-to-digital converter (adc-15) 23.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411 23.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412 23.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412 23.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412 23.5 interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415 23.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .415 23.7 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416 23.8 i/o registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417 section 24. electrical specifications 24.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423 24.2 maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424 24.3 functional operating range. . . . . . . . . . . . . . . . . . . . . . . . . . 425 24.4 thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425 24.5 5.0 volt dc electrical characteristics . . . . . . . . . . . . . . . . . . . 426 table of contents technical data MC68HC08AZ32A ? rev 1.0 16 table of contents motorola 24.6 control timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427 24.7 adc characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428 24.8 5.0 vdc 0.5 v serial peripheral interface (spi) timing . . . . 429 24.9 cgm operating conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . 432 24.10 cgm component information. . . . . . . . . . . . . . . . . . . . . . . . . 433 24.11 cgm acquisition/lock time information . . . . . . . . . . . . . . . . 434 24.12 ram memory characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 435 24.13 eeprom memory characteristics . . . . . . . . . . . . . . . . . . . . . 435 24.14 mechanical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . 436 section 25. MC68HC08AZ32A changes 25.1 contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437 25.2 significant changes from the mc68hc08az32 (non-a suffix de- vice) 437 revision history major changes between revision 1.0 and revision 0.0 . . . .443 glossary MC68HC08AZ32A ? rev 1.0 technical data motorola list of figures 17 technical data ? MC68HC08AZ32A list of figures figure title page 1-1 MC68HC08AZ32A mcu block diagram . . . . . . . . . . . . . . . . . 30 1-2 64 qfp pin assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1-3 power supply bypassing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2-1 MC68HC08AZ32A memory map . . . . . . . . . . . . . . . . . . . . . . . 42 2-2 i/o data, status and control registers . . . . . . . . . . . . . . . . . . 45 2-3 additional status and control registers . . . . . . . . . . . . . . . . . . 49 5-1 eeprom register summary . . . . . . . . . . . . . . . . . . . . . . . . . . 59 5-2 eeprom control register (eecr) . . . . . . . . . . . . . . . . . . . . . 67 5-3 eeprom array configuration register (eeacr) . . . . . . . . . . 69 5-4 eeprom nonvolatile register (eenvr) . . . . . . . . . . . . . . . . . 71 5-5 eediv divider high register (eedivh) . . . . . . . . . . . . . . . . . . 72 5-6 eediv divider low register (eedivl). . . . . . . . . . . . . . . . . . . 72 5-7 eeprom divider non-volatile register high (eedivhnvr)) . 74 5-8 eeprom divider non-volatile register low (eedivlnvr) . . 74 6-1 cpu registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 6-2 accumulator (a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 6-3 index register (h:x) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 6-4 stack pointer (sp) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80 6-5 program counter (pc) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 6-6 condition code register (ccr) . . . . . . . . . . . . . . . . . . . . . . . . 81 7-1 sim block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 7-2 cgm clock signals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 7-3 external reset timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 7-4 internal reset timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 7-5 sources of internal reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 7-6 por recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 7-7 interrupt entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 7-8 interrupt recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106 7-9 interrupt recognition example . . . . . . . . . . . . . . . . . . . . . . . . 107 list of figures technical data MC68HC08AZ32A ? rev 1.0 18 list of figures motorola 7-10 wait mode entry timing . . . . . . . . . . . . . . . . . . . . . . . . . . . .110 7-11 wait recovery from interrupt or break . . . . . . . . . . . . . . . . 110 7-12 wait recovery from internal reset . . . . . . . . . . . . . . . . . . .110 7-13 stop mode entry timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 7-14 stop mode recovery from interrupt . . . . . . . . . . . . . . . . . . 112 7-15 sim break status register (sbsr) . . . . . . . . . . . . . . . . . . . .112 7-16 sim reset status register (srsr) . . . . . . . . . . . . . . . . . . . . 114 7-17 sim break flag control register (sbfcr) . . . . . . . . . . . . . . 115 8-1 cgm block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 8-2 i/o register summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 8-3 cgm external connections . . . . . . . . . . . . . . . . . . . . . . . . . .129 8-4 pll control register (pctl) . . . . . . . . . . . . . . . . . . . . . . . . . 131 8-5 pll bandwidth control register (pbwc) . . . . . . . . . . . . . . . 133 8-6 pll programming register (ppg) . . . . . . . . . . . . . . . . . . . . . 135 9-1 mask option register a (mora) . . . . . . . . . . . . . . . . . . . . . . 146 9-2 mask option register b (morb) . . . . . . . . . . . . . . . . . . . . . . 148 10-1 break module block diagram . . . . . . . . . . . . . . . . . . . . . . . . . 151 10-2 break status and control register (brkscr). . . . . . . . . . . . 153 10-3 break address registers (brkh and brkl) . . . . . . . . . . . . . 154 11-1 monitor mode circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 11-2 monitor data format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 11-3 sample monitor waveforms . . . . . . . . . . . . . . . . . . . . . . . . . .159 11-4 read transaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 11-5 break transaction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 11-6 monitor mode entry timing. . . . . . . . . . . . . . . . . . . . . . . . . . . 165 12-1 cop block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 12-2 cop control register (copctl) . . . . . . . . . . . . . . . . . . . . . .171 13-1 lvi module block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 13-2 lvi status register (lvisr) . . . . . . . . . . . . . . . . . . . . . . . . . . 176 14-1 irq module block diagram . . . . . . . . . . . . . . . . . . . . . . . . . .180 14-2 irq interrupt flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 14-3 irq status and control register (iscr) . . . . . . . . . . . . . . . . 184 15-1 sci module block diagram . . . . . . . . . . . . . . . . . . . . . . . . 190 15-2 sci i/o register summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 15-3 sci data formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 15-4 sci transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 15-5 sci transmitter i/o register summary . . . . . . . . . . . . . . . . . 195 15-6 sci receiver block diagram . . . . . . . . . . . . . . . . . . . . . . 198 list of figures MC68HC08AZ32A ? rev 1.0 technical data motorola list of figures 19 15-7 sci i/o receiver register summary . . . . . . . . . . . . . . . . . . .199 15-8 receiver data sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . .201 15-9 slow data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 15-10 fast data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .204 15-11 sci control register 1 (scc1). . . . . . . . . . . . . . . . . . . . . . . .210 15-12 sci control register 2 (scc2). . . . . . . . . . . . . . . . . . . . . . . .213 15-13 sci control register 3 (scc3). . . . . . . . . . . . . . . . . . . . . . . .215 15-14 sci status register 1 (scs1) . . . . . . . . . . . . . . . . . . . . . . . . 217 15-15 flag clearing sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . .219 15-16 sci status register 2 (scs2) . . . . . . . . . . . . . . . . . . . . . . . . 221 15-17 sci data register (scdr) . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 15-18 sci baud rate register (scbr) . . . . . . . . . . . . . . . . . . . . . . 223 16-1 spi i/o register summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 230 16-2 spi module block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . 231 16-3 full-duplex master-slave connections . . . . . . . . . . . . . . . . . . 233 16-4 transmission format (cpha = ? 0 ? ). . . . . . . . . . . . . . . . . . . . . 236 16-5 transmission format (cpha = ? 1 ? ). . . . . . . . . . . . . . . . . . . . . 237 16-6 transmission start delay (master) . . . . . . . . . . . . . . . . . . . . . 238 16-7 missed read of overflow condition . . . . . . . . . . . . . . . . . . . . 240 16-8 clearing sprf when ovrf interrupt is not enabled . . . . . . 241 16-9 spi interrupt request generation . . . . . . . . . . . . . . . . . . . . . 244 16-10 sprf/spte cpu interrupt timing . . . . . . . . . . . . . . . . . . . . . 245 16-11 cpha/ss timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 16-12 spi control register (spcr) . . . . . . . . . . . . . . . . . . . . . . . . . 252 16-13 spi status and control register (spscr) . . . . . . . . . . . . . . .255 16-14 spi data register (spdr) . . . . . . . . . . . . . . . . . . . . . . . . . . . 258 17-1 timb block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261 17-2 timb i/o register summary. . . . . . . . . . . . . . . . . . . . . . . . . . 261 17-3 pwm period and pulse width . . . . . . . . . . . . . . . . . . . . . . . . 266 17-4 timb status and control register (tbsc) . . . . . . . . . . . . . . .273 17-5 timb counter registers (tbcnth and tbcntl) . . . . . . . . . 275 17-6 timb counter modulo registers (tbmodh and tbmodl) .276 17-7 timb channel status and control registers (tbsc0 ? tbsc1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277 17-8 chxmax latency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281 17-9 timb channel registers (tbch0h/l ? tbch1h/l) . . . . . . . . 282 18-1 pit block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .284 18-2 pit i/o register summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 285 list of figures technical data MC68HC08AZ32A ? rev 1.0 20 list of figures motorola 18-3 pit status and control register (psc) . . . . . . . . . . . . . . . . . 288 18-4 pit counter registers (pcnth ? pcntl). . . . . . . . . . . . . . . . 290 18-5 pit counter modulo registers (pmodh ? pmodl) . . . . . . . . 291 19-1 port a data register (pta) . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 19-2 data direction register a (ddra). . . . . . . . . . . . . . . . . . . . . 296 19-3 port a i/o circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296 19-4 port b data register (ptb) . . . . . . . . . . . . . . . . . . . . . . . . . .298 19-5 data direction register b (ddrb) . . . . . . . . . . . . . . . . . . . . . 299 19-6 port b i/o circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 19-7 port c data register (ptc) . . . . . . . . . . . . . . . . . . . . . . . . . .301 19-8 data direction register c (ddrc) . . . . . . . . . . . . . . . . . . . . . 302 19-9 port c i/o circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 19-10 port d data register (ptd) . . . . . . . . . . . . . . . . . . . . . . . . . .304 19-11 data direction register d (ddrd) . . . . . . . . . . . . . . . . . . . . . 305 19-12 port d i/o circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306 19-13 port e data register (pte) . . . . . . . . . . . . . . . . . . . . . . . . . .307 19-14 data direction register e (ddre) . . . . . . . . . . . . . . . . . . . . . 310 19-15 port e i/o circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310 19-16 port f data register (ptf). . . . . . . . . . . . . . . . . . . . . . . . . . . 312 19-17 data direction register f (ddrf) . . . . . . . . . . . . . . . . . . . . . 313 19-18 port f i/o circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314 19-19 port g data register (ptg) . . . . . . . . . . . . . . . . . . . . . . . . . .315 19-20 data direction register g (ddrg). . . . . . . . . . . . . . . . . . . . . 316 19-21 port g i/o circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316 19-22 port h data register (pth) . . . . . . . . . . . . . . . . . . . . . . . . . .318 19-23 data direction register h (ddrh) . . . . . . . . . . . . . . . . . . . . . 319 19-24 port h i/o circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319 20-1 the can system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324 20-2 user model for message buffer organization. . . . . . . . . . . . . 328 20-3 single 32-bit maskable identifier acceptance filter . . . . . . . .331 20-4 dual 16-bit maskable acceptance filters . . . . . . . . . . . . . . . . 332 20-5 quadruple 8-bit maskable acceptance filters . . . . . . . . . . . .333 20-6 sleep request/acknowledge cycle . . . . . . . . . . . . . . . . . . . . 340 20-7 clocking scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343 20-8 segments within the bit time . . . . . . . . . . . . . . . . . . . . . . . . 345 20-9 mscan08 memory map. . . . . . . . . . . . . . . . . . . . . . . . . . . . .346 20-10 message buffer organization . . . . . . . . . . . . . . . . . . . . . . . . .347 20-11 receive/transmit message buffer extended identifier (idrn) list of figures MC68HC08AZ32A ? rev 1.0 technical data motorola list of figures 21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348 20-12 standard identifier mapping . . . . . . . . . . . . . . . . . . . . . . . . . .350 20-13 transmit buffer priority register (tbpr) . . . . . . . . . . . . . . . . 352 20-14 mscan08 control register structure . . . . . . . . . . . . . . . . . . 353 20-15 module control register 0 (cmcr0) . . . . . . . . . . . . . . . . . . .355 20-16 module control register (cmcr1). . . . . . . . . . . . . . . . . . . . . 357 20-17 bus timing register 0 (cbtr0) . . . . . . . . . . . . . . . . . . . . . . . 358 20-18 bus timing register 1 (cbtr1) . . . . . . . . . . . . . . . . . . . . . . . 359 20-19 receiver flag register (crflg) . . . . . . . . . . . . . . . . . . . . . . 361 20-20 receiver interrupt enable register (crier) . . . . . . . . . . . . . 363 20-21 transmitter flag register (ctflg) . . . . . . . . . . . . . . . . . . . . 365 20-22 transmitter control register (ctcr) . . . . . . . . . . . . . . . . . . . 366 20-23 identifier acceptance control register (cidac). . . . . . . . . . . 367 20-24 receiver error counter (crxerr) . . . . . . . . . . . . . . . . . . . . 369 20-25 transmit error counter (ctxerr). . . . . . . . . . . . . . . . . . . . . 369 20-26 identifier acceptance registers (cidar0 ? cidar3) . . . . . . . 370 20-27 identifier mask registers (cidmr0 ? cidmr3) . . . . . . . . . . . . 371 21-1 keyboard module block diagram . . . . . . . . . . . . . . . . . . . . 375 21-2 i/o register summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375 21-3 keyboard status and control register (kbscr) . . . . . . . . . . 379 21-4 keyboard interrupt enable register (kbier) . . . . . . . . . . . . . 380 22-1 tima block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 22-2 tima i/o register summary. . . . . . . . . . . . . . . . . . . . . . . . . . 384 22-3 pwm period and pulse width . . . . . . . . . . . . . . . . . . . . . . . . 390 22-4 tima status and control register (tasc) . . . . . . . . . . . . . . .398 22-5 tima counter registers (tacnth and tacntl) . . . . . . . . . 400 22-6 tima counter modulo registers (tamodh and tamodl) .401 22-7 tima channel status and control registers (tasc0 ? tasc5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403 22-8 chxmax latency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407 22-9 tima channel registers (tach0h/l ? tach5h/l) . . . . . . . . 408 23-1 adc block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413 23-2 adc status and control register (adscr) . . . . . . . . . . . . . . 417 23-3 adc data register (adr) . . . . . . . . . . . . . . . . . . . . . . . . . . . 420 23-4 adc input clock register (adiclk) . . . . . . . . . . . . . . . . . . .420 24-1 spi master timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . .430 24-2 spi slave timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . 431 24-3 64-pin qfp (case #840b) . . . . . . . . . . . . . . . . . . . . . . . . . . . 436 list of figures technical data MC68HC08AZ32A ? rev 1.0 22 list of figures motorola MC68HC08AZ32A ? rev 1.0 technical data motorola list of tables 23 technical data ? MC68HC08AZ32A list of tables table title page 1-1 external pins summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 1-2 signal name conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 1-3 clock source summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 1-4 mc order numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2-1 vector addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 5-1 eeprom array address blocks. . . . . . . . . . . . . . . . . . . . . . . . 62 5-2 example selective bit programming description . . . . . . . . . . . 63 5-3 eeprom program/erase mode select . . . . . . . . . . . . . . . . . . 68 5-4 eeprom block protect and security summary. . . . . . . . . . . . 70 6-1 instruction set summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 6-2 opcode map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 7-1 sim i/o register summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 7-2 signal naming conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 7-3 pin bit set timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100 7-4 sim registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 8-1 i/o register address summary . . . . . . . . . . . . . . . . . . . . . . . 121 8-2 variable definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 8-3 vco frequency multiplier (n) selection. . . . . . . . . . . . . . . . . 136 10-1 break i/o register summary . . . . . . . . . . . . . . . . . . . . . . . . . 151 11-1 mode selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .158 11-2 mode differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 11-3 read (read memory) command . . . . . . . . . . . . . . . . . . . . . 161 11-4 write (write memory) command. . . . . . . . . . . . . . . . . . . . . 161 11-5 iread (indexed read) command . . . . . . . . . . . . . . . . . . . . . 162 11-6 iwrite (indexed write) command . . . . . . . . . . . . . . . . . . . . 162 11-7 readsp (read stack pointer) command . . . . . . . . . . . . . . .163 11-8 run (run user program) command . . . . . . . . . . . . . . . . . . . 163 12-1 cop i/o register summary . . . . . . . . . . . . . . . . . . . . . . . . . . 168 13-1 lvi i/o register summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 list of tables technical data MC68HC08AZ32A ? rev 1.0 24 list of tables motorola 13-2 lviout bit indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 14-1 irq i/o register summary. . . . . . . . . . . . . . . . . . . . . . . . . . . 181 15-1 pin name conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 15-2 sci i/o register address summary . . . . . . . . . . . . . . . . . . . . 191 15-3 sci transmitter i/o address summary . . . . . . . . . . . . . . . . . 195 15-4 sci receiver i/o address summary . . . . . . . . . . . . . . . . . . .199 15-5 start bit verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 15-6 data bit recovery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 15-7 stop bit recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 15-8 character format selection . . . . . . . . . . . . . . . . . . . . . . . . . .212 15-9 sci baud rate prescaling . . . . . . . . . . . . . . . . . . . . . . . . . . . 223 15-10 sci baud rate selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 15-11 sci baud rate selection examples . . . . . . . . . . . . . . . . . . . . 225 16-1 pin name conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229 16-2 i/o register addresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229 16-3 spi interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 16-4 spi configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 16-5 spi master baud rate selection . . . . . . . . . . . . . . . . . . . . . . 257 17-1 prescaler selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274 17-2 mode, edge, and level selection . . . . . . . . . . . . . . . . . . . . . .280 18-1 pit i/o register address summary . . . . . . . . . . . . . . . . . . . . 285 18-2 prescaler selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 19-1 i/o port register summary. . . . . . . . . . . . . . . . . . . . . . . . . . . 294 19-2 port a pin functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297 19-3 port b pin functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 19-4 port c pin functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 19-5 port d pin functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306 19-6 port e pin functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311 19-7 port f pin functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314 19-8 port g pin functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317 19-9 port h pin functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320 20-1 mscan08 interrupt vector addresses . . . . . . . . . . . . . . . . . . 337 20-2 mscan08 vs cpu operating modes . . . . . . . . . . . . . . . . . . . 338 20-3 time segment syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345 20-4 can standard compliant bit time segment settings . . . . . . 345 20-5 data length codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351 20-6 synchronization jump width . . . . . . . . . . . . . . . . . . . . . . . . . 358 20-7 baud rate prescaler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359 list of tables MC68HC08AZ32A ? rev 1.0 technical data motorola list of tables 25 20-8 time segment values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 20-9 identifier acceptance mode settings . . . . . . . . . . . . . . . . . . .368 20-10 identifier acceptance hit indication . . . . . . . . . . . . . . . . . . . . 368 21-1 i/o register address summary . . . . . . . . . . . . . . . . . . . . . . . 375 22-1 prescaler selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399 22-2 mode, edge, and level selection . . . . . . . . . . . . . . . . . . . . . .406 23-1 mux channel select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419 23-2 adc clock divide ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421 list of tables technical data MC68HC08AZ32A ? rev 1.0 26 list of tables motorola MC68HC08AZ32A ? rev 1.0 technical data motorola general description 27 technical data ? MC68HC08AZ32A section 1. general description 1.1 contents 1.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.4 pin assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1.4.1 power supply pins (v dd and v ss ) . . . . . . . . . . . . . . . . . . . 32 1.4.2 oscillator pins (osc1 and osc2) . . . . . . . . . . . . . . . . . . . 33 1.4.3 external reset pin (rst) . . . . . . . . . . . . . . . . . . . . . . . . . . 33 1.4.4 external interrupt pin (irq) . . . . . . . . . . . . . . . . . . . . . . . . 33 1.4.5 analog power supply pin (v dda ) . . . . . . . . . . . . . . . . . . . 33 1.4.6 analog ground pin (v ssa ) . . . . . . . . . . . . . . . . . . . . . . . . . 33 1.4.7 adc analog ground pin (a vss /v refl ) . . . . . . . . . . . . . . . 33 1.4.8 adc reference high voltage pin (vrefh) . . . . . . . . . . . 34 1.4.9 adc analog power supply pin (v ddaref ) . . . . . . . . . . . . 34 1.4.10 external filter capacitor pin (cgmxfc) . . . . . . . . . . . . . 34 1.4.11 port a input/output (i/o) pins (pta7 ? pta0) . . . . . . . . . . 34 1.4.12 port b i/o pins (ptb7/atd7 ? ptb0/atd0) . . . . . . . . . . . . 34 1.4.13 port c i/o pins (ptc5 ? ptc0) . . . . . . . . . . . . . . . . . . . . . . 34 1.4.14 port d i/o pins (ptd7 ? ptd0/atd8) . . . . . . . . . . . . . . . . . 35 1.4.15 port e i/o pins (pte7/spsck ? pte0/txd) . . . . . . . . . . . . 35 1.4.16 port f i/o pins (ptf6 ? ptf0/tach2) . . . . . . . . . . . . . . . . . 35 1.4.17 port g i/o pins (ptg2/kbd2 ? ptg0/kbd0) . . . . . . . . . . . 35 1.4.18 port h i/o pins (pth1/kbd4 ? pth0/kbd3) . . . . . . . . . . . . 36 1.4.19 can transmit pin (txcan) . . . . . . . . . . . . . . . . . . . . . . . . 36 1.4.20 can receive pin (rxcan) . . . . . . . . . . . . . . . . . . . . . . . . . 36 1.5 ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 1.5.1 mc order numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 general description technical data MC68HC08AZ32A ? rev 1.0 28 general description motorola 1.2 introduction the MC68HC08AZ32A is a member of the low-cost, high-performance m68hc08 family of 8-bit microcontroller units (mcus). the m68hc08 family is based on the customer-specified integrated circuit (csic) design strategy. all mcus in the family use the enhanced m68hc08 central processor unit (cpu08) and are available with a variety of modules, memory sizes and types, and package types. 1.3 features features of the MC68HC08AZ32A include the following: high-performance m68hc08 architecture fully upward-compatible object code with m6805, m146805, and m68hc05 families 8.4mhz internal bus frequency at 125 c mscan08 controller (motorola scalable can) (implementing can 2.0b protocol as defined in bosch specification sep. 1991) available in 64 qfp package 32,256 bytes user rom user rom data security 512 bytes of on-chip eeprom with security feature 1k byte of on-chip ram serial peripheral interface (spi) module serial communications interface (sci) module 16-bit timer interface module (tima-6) with six input capture/output compare channels 16-bit timer interface module (timb) with two input capture/output compare channels programmable interrupt timer (pit) clock generator module (cgm) general description features MC68HC08AZ32A ? rev 1.0 technical data motorola general description 29 8-bit, 15-channel analog to digital convertor (adc-15) 5-bit keyboard interrupt module system protection features ? computer operating properly (cop) with optional reset ? low-voltage detection with optional reset ? illegal opcode detection with optional reset ? illegal address detection with optional reset low-power design (fully static with stop and wait modes) master reset pin and power-on reset features of the cpu08 include the following: enhanced hc05 programming model extensive loop controlfunctions 16 addressing modes (8 more than the hc05) 16-bit index register and stack pointer memory-to-memory data transfers fast 8 8 multiply instruction fast 16/8 divide instruction binary-coded decimal (bcd) instructions optimization for controller applications ? c ? language support figure 1-1 shows the structure of the MC68HC08AZ32A technical data MC68HC08AZ32A ? rev 1.0 30 general description motorola general description . figure 1-1. MC68HC08AZ32A mcu block diagram pta7-pta0 mscan08 controller module break module clock generator module system integration module serial peripheral interface module timera & b interface modules low voltage inhibit module power-on reset module computer operating properly module arithmetic/logic unit (alu) cpu registers m68hc08 cpu control and status registers user ram ? 1024 bytes user eeprom ? 512 bytes user rom ? 32,256 bytes monitor rom ? 256 bytes irq module power pta ddra ddrb ptb ddrc ptc ddrd ptd ddre pte ptf ddrf ptg ddrg user rom vector space ? 52 bytes analog to digital convertor module (6 + 2 channels) programmable interrupt timer module serial communications ptb7/atd7-ptb0/atd0 ptc5-ptc3 ptd5/atd13 pte7/spsck pte6/mosi pte5/miso pte4/ss pte3/tach1 pte2/tach0 pte1/rxd pte0/txd ptf5/tbch1- ptf4/tbch0 ptf3/tach5- ptf0/tach2 ptg2/kbd2- ptg0/kbd0 vrefh a vss /vrefl v ddaref v dd v ss v ssa v dda rst irq osc1 osc2 cgmxfc rxcan txcan ptf6 pth ddrh pth1/kbd4- pth0/kbd3 interface module keyboard interrupt module ptc2/mclk ptc1-ptc0 ptd7 ptd6/atd14/taclk ptd4/atd12/tbclk ptd3/atd11- ptd0/atd8 general description pin assignments MC68HC08AZ32A ? rev 1.0 technical data motorola general description 31 1.4 pin assignments figure 1-2 shows the 64 qfp pin assignments. figure 1-2. 64 qfp pin assignments txcan ptf4/tbch0 cgmxfc ptb7/atd7 ptf3/tach5 ptf2/tach4 ptf1/tach3 ptf0/tach2 rst irq ptc4 rxcan ptf5/tbch1 ptf6 pte0/txd pte1/rxd pte2/tach0 pte3/tach1 pth0/kbd3 ptd3/atd11 ptd2/atd10 a vss /vrefl v ddaref ptd1/atd9 ptd0/atd8 ptb6/atd6 ptb5/atd5 ptb4/atd4 ptb3/atd3 ptb2/atd2 ptb1/atd1 ptb0/atd0 pta7 v ssa v dda vrefh ptd7 ptd6/atd14/taclk ptd5/atd13 ptd4/atd12/tbclk pth1/kbd4 ptc5 ptc3 ptc2/mclk ptc1 ptc0 osc1 osc2 pte6/mosi pte4/ss pte5/miso pte7/spsck v ss v dd ptg0/kbd0 ptg1/kbd1 ptg2/kbd2 pta0 pta1 pta2 pta3 pta4 pta5 pta6 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 MC68HC08AZ32A general description technical data MC68HC08AZ32A ? rev 1.0 32 general description motorola 1.4.1 power supply pins (v dd and v ss ) v dd and v ss are the power supply and ground pins. the mcu operates from a single power supply. fast signal transitions on mcu pins place high, short-duration current demands on the power supply. to prevent noise problems, take special care to provide power supply bypassing at the mcu as figure 1-3 shows. place the c1 bypass capacitor as close to the mcu as possible. use a high-frequency-response ceramic capacitor for c1. c2 is an optional bulk current bypass capacitor for use in applications that require the port pins to source high current levels. figure 1-3. power supply bypassing v ss is also the ground for the port output buffers and the ground return for the serial clock in the serial peripheral interface module (spi). see serial peripheral interface (spi) on page 227. note: v ss must be grounded for proper mcu operation. mcu v dd c2 c1 0.1 f v ss v dd + note: component values shown represent typical applications. general description pin assignments MC68HC08AZ32A ? rev 1.0 technical data motorola general description 33 1.4.2 oscillator pins (osc1 and osc2) the osc1 and osc2 pins are the connections for the on-chip oscillator circuit. see clock generator module (cgm) on page 117. 1.4.3 external reset pin (rst ) a logic ? 0 ? on the rst pin forces the mcu to a known start-up state. rst is bidirectional, allowing a reset of the entire system. it is driven low when any internal reset source is asserted. see system integration module (sim) on page 95. 1.4.4 external interrupt pin (irq ) irq is an asynchronous external interrupt pin. see external interrupt module (irq) on page 179. 1.4.5 analog power supply pin (v dda ) v dda is the power supply pin for the analog portion of the clock generator module (cgm). see clock generator module (cgm) on page 117. 1.4.6 analog ground pin (v ssa ) v ssa is the ground connection for the analog portion of the clock generator module (cgm). see clock generator module (cgm) on page 117. 1.4.7 adc analog ground pin (a vss /v refl ) the av ss /v refl pin provides both the analog ground connection and the reference low voltage for the analog-to-digital converter (adc). see analog-to-digital converter (adc-15) on page 411. general description technical data MC68HC08AZ32A ? rev 1.0 34 general description motorola 1.4.8 adc reference high voltage pin (v refh ) v refh provides the reference high voltage for the analog-to-digital converter (adc). see analog-to-digital converter (adc-15) on page 411. 1.4.9 adc analog power supply pin (v ddaref ) v ddaref is the power supply pin for the analog portion of the analog-to- digital converter (adc). see analog-to-digital converter (adc-15) on page 411. 1.4.10 external filter capacitor pin (cgmxfc) cgmxfc is an external filter capacitor connection for the clock generator module (cgm). see clock generator module (cgm) on page 117. 1.4.11 port a input/output (i/o) pins (pta7 ? pta0) pta7 ? pta0 are general-purpose bidirectional i/o port pins. see i/o ports on page 293. 1.4.12 port b i/o pins (ptb7/atd7 ? ptb0/atd0) port b is an 8-bit special function port that shares all eight pins with the analog to digital convertor (adc). see analog-to-digital converter (adc-15) on page 411 and i/o ports on page 293. 1.4.13 port c i/o pins (ptc5 ? ptc0) ptc5 ? ptc3 and ptc1 ? ptc0 are general-purpose bidirectional i/o port pins. ptc2/mclk is a special function port that shares its pin with the system clock. see i/o ports on page 293. general description pin assignments MC68HC08AZ32A ? rev 1.0 technical data motorola general description 35 1.4.14 port d i/o pins (ptd7 ? ptd0/atd8) port d is an 8-bit special-function port that shares seven of its pins with the analog-to-digital converter module (adc-15), one of its pins with the timer interface module a (tima-6), and one more of its pins with the timer interface module b (timb). see timer interface module a (tima) on page 381 , timer interface module b (timb) on page 259, analog-to-digital converter (adc-15) on page 411 and i/o ports on page 293. 1.4.15 port e i/o pins (pte7/spsck ? pte0/txd) port e is an 8-bit special function port that shares two of its pins with the timer interface module a (tima), four of its pins with the serial peripheral interface module (spi), and two of its pins with the serial communication interface module (sci). see serial communications interface (sci) on page 187, serial peripheral interface (spi) on page 227, timer interface module a (tima) on page 381 and i/o ports on page 293. 1.4.16 port f i/o pins (ptf6 ? ptf0/tach2) port f is a 7-bit special function port that shares its pins with the timer interface module b (timb). six of its pins are shared with the timer interface module a (tima-6). see timer interface module a (tima) on page 381, timer interface module b (timb) on page 259 and i/o ports on page 293. 1.4.17 port g i/o pins (ptg2/kbd2 ? ptg0/kbd0) port g is a 3-bit special function port that shares all of its pins with the keyboard module (kbd). see keyboard module (kbd) on page 373 and i/o ports on page 293. general description technical data MC68HC08AZ32A ? rev 1.0 36 general description motorola 1.4.18 port h i/o pins (pth1/kbd4 ? pth0/kbd3) port h is a 2-bit special-function port that shares all of its pins with the keyboard module (kbd). see keyboard module (kbd) on page 373 and i/o ports on page 293. 1.4.19 can transmit pin (txcan) txcan is the digital output from the mscan08 module. see mscan08 controller (mscan08) on page 321. 1.4.20 can receive pin (rxcan) rxcan is the digital input to the mscan08 module. see mscan08 controller (mscan08) on page 321. table 1-1. external pins summary pin name function driver type hysteresis (1) reset state pta7 ? pta0 general purpose i/o dual state no input (hi-z) ptb7/atd7 ? ptb0/atd0 general purpose i/0 / adc channel dual state no input (hi-z) ptc5 ? ptc0 general purpose i/o dual state no input (hi-z) ptd7 general purpose i/o dual state no input (hi-z) ptd6/atd14/taclk general purpose i/o/adc channel/timer a external input clock dual state yes (only for timer a function) input (hi-z) ptd5/atd13 general purpose i/o/adc channel dual state no input (hi-z) ptd4/atd12/tbclk general purpose i/o /adc channel/timer b external input clock dual state yes (only for timer b function) input (hi-z) ptd3/atd11?ptd0/a td8 general purpose i/o /adc channel dual state no input (hi-z) pte7/spsck general purpose i/0 / spi clock dual state (open drain) yes (only for spi func- tion) input (hi-z) pte6/mosi general purpose i/0 / spi data path dual state (open drain) yes (only for spi func- tion) input (hi-z) pte5/miso general purpose i/0 / spi data path dual state (open drain) yes (only for spi func- tion) input (hi-z) general description pin assignments MC68HC08AZ32A ? rev 1.0 technical data motorola general description 37 pte4/ss general purpose i/0 / spi slave select dual state yes (only for spi func- tion) input (hi-z) pte3/tach1 general purpose i/0 / timera channel 1 dual state yes (only for timer a function) input (hi-z) pte2/tach0 general purpose i/0 / timera channel 0 dual state yes (only for timer a function) input (hi-z) pte1/rxd general purpose i/0 / sci receive data dual state yes (only for sci func- tion) input (hi-z) pte0/txd general purpose i/0 / sci transmit data dual state no input (hi-z) ptf6 general purpose i/o dual state no input (hi-z) ptf5/tbch1 general purpose i/o /timer b channel 1 dual state yes (only for timer b function) input (hi-z) ptf4/tbch0 general purpose i/0 / timer b channel 0 dual state yes (only for timer b function) input (hi-z) ptf3/tach5 general purpose i/0/timer a channel 5 dual state yes (only for timer a function) input (hi-z) ptf2/tach4 general purpose i/0/timer a channel 4 dual state yes (only for timer a function) input (hi-z) ptf1/tach3 general purpose i/0 /timer a channel 3 dual state yes (only for timer a function) input (hi-z) ptf0/tach2 general purpose i/0 /timer a channel 2 dual state yes (only for timer a function) input (hi-z) ptg2/kbd2 ? ptg0/kbd0 general purpose i/0/keyboard wakeup pin dual state yes (only for kbd func- tion) input (hi-z) pth1/kbd4 ? pth0/kbd3 general purpose i/0/keyboard wakeup pin dual state yes (only for kbd func- tion) input (hi-z) v dd logical chip power supply na na na v ss logical chip ground na na na v dda cgm analog power supply na na na v ssa cgm analog ground na na na vrefh adc reference high voltage na na na a vss /vrefl adc gnd & reference low voltage na na na table 1-1. external pins summary (continued) pin name function driver type hysteresis (1) reset state general description technical data MC68HC08AZ32A ? rev 1.0 38 general description motorola details of the clock connections to each of the modules on the MC68HC08AZ32A are shown in table 1-3 . a short description of each clock source is also given in table 1-2 . v ddaref adc power supply na na na osc1 external clock in na na input (hi-z) osc2 external clock out na na output cgmxfc pll loop filter cap na na na irq external interrupt request na na input (hi-z) rst reset na na input (hi-z) rxcan mscan08 serial input na yes input (hi-z) txcan mscan08 serial output output na output 1. hysteresis is not 100% tested but is typically a minimum of 300mv. table 1-1. external pins summary (continued) pin name function driver type hysteresis (1) reset state table 1-2. signal name conventions signal name description cgmxclk buffered version of osc1 from clock generator module (cgm) cgmout pll-based or osc1-based clock output from clock generator module (cgm) bus clock cgmout divided by two spsck spi serial clock taclk external clock input for tima tbclk external clock input for timb table 1-3. clock source summary module clock source adc cgmxclk or bus clock mscan08 cgmxclk or cgmout cop cgmxclk cpu bus clock general description ordering information MC68HC08AZ32A ? rev 1.0 technical data motorola general description 39 1.5 ordering information this section contains instructions for ordering the MC68HC08AZ32A. 1.5.1 mc order numbers eeprom cgmxclk or bus clock rom bus clock ram bus clock spi bus clock/spsck sci cgmxclk tima bus clock or ptd6/atd14/taclk timb bus clock or ptd4/atd12/tbclk pit bus clock kbi bus clock sim cgmout and cgmxclk irq bus clock brk bus clock lvi bus clock cgm osc1 and osc2 table 1-3. clock source summary (continued) module clock source table 1-4. mc order numbers mc order number operating temperature range MC68HC08AZ32Acfu ? 40 c to + 85 c MC68HC08AZ32Avfu ? 40 c to + 105 c MC68HC08AZ32Amfu ? 40 c to + 125 c general description technical data MC68HC08AZ32A ? rev 1.0 40 general description motorola MC68HC08AZ32A ? rev 1.0 technical data motorola memory map 41 technical data ? MC68HC08AZ32A section 2. memory map 2.1 contents 2.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 2.3 i/o section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 2.4 additional status and control registers . . . . . . . . . . . . . . . 49 2.5 vector addresses and priority . . . . . . . . . . . . . . . . . . . . . . . 50 2.2 introduction the cpu08 can address 64k bytes of memory space. the memory map includes: 1024 bytes of ram 32,256 bytes of user rom 512 bytes of eeprom 52 bytes of user-defined vectors 256 bytes of monitor rom the following definitions apply to the memory map representation of reserved and unimplemented locations. reserved ? accessing a reserved location can have unpredictable effects on mcu operation. unimplemented ? accessing an unimplemented location can cause an illegal address reset (within the constraints as outlined in system integration module (sim) on page 95. memory map technical data MC68HC08AZ32A ? rev 1.0 42 memory map motorola $0000 i/o registers (80 bytes) $004f $0050 ram (1024 bytes) $044f $0450 unimplemented (176 bytes) $04ff $0500 can control and message buffers(128 bytes) $057f $0580 unimplemented (640 bytes) $07ff $0800 eeprom (512 bytes) $09ff $0a00 unimplemented (1536 bytes) $0fff $1000 unimplemented ( 28,672 bytes) $7fff $8000 rom (16,384bytes) $bfff $c000 rom (15,872 bytes) $fdff $fe00 sim break status register (sbsr) $fe01 sim reset status register (srsr) figure 2-1. MC68HC08AZ32A memory map memory map introduction MC68HC08AZ32A ? rev 1.0 technical data motorola memory map 43 $fe02 reserved $fe03 sim break flag control register (sbfcr) $fe04 reserved $fe05 reserved $fe06 reserved $fe07 reserved $fe08 reserved $fe09 morb $fe0a reserved $fe0b reserved $fe0c break address register high (brkh) $fe0d break address register low (brkl) $fe0e break status and control register (brkscr) $fe0f lvi status register (lvisr) $fe10 eeprom-eedivh non-volatile register(eedivhnvr) $fe11 eeprom-eedivl non-volatile register(eedivlnvr) $fe12 reserved (8 bytes) $fe19 $fe1a eeprom-eedivh register(eedivh) $fe1b eeprom-eedivl register(eedivl) $fe1c eeprom non-volatile register (eenvr) $fe1d eeprom control register (eecr) $fe1e reserved $fe1f eeprom array configuration (eeacr) $fe20 monitor rom (256 bytes) $ff1f figure 2-1. MC68HC08AZ32A memory map memory map technical data MC68HC08AZ32A ? rev 1.0 44 memory map motorola $ff20 unimplemented (160 bytes) $ffbf $ffc0 reserved (12 bytes) $ffcb $ffcc vectors (52 bytes) $ffff figure 2-1. MC68HC08AZ32A memory map memory map i/o section MC68HC08AZ32A ? rev 1.0 technical data motorola memory map 45 2.3 i/o section addresses $0000 ? $004f, shown in figure 2-2 , contain the i/o data, status and control registers addr. name bit 76 5 4 3 2 1bit 0 $0000 port a data register (pta) r: pta7 pta6 pta5 pta4 pta3 pta2 pta1 pta0 w: $0001 port b data register (ptb) r: ptb7 ptb6 ptb25 ptb4 ptb3 ptb2 ptb1 ptb0 w: $0002 port c data register (ptc) r: 0 0 ptc5 ptc4 ptc3 ptc2 ptc1 ptc0 w: r r $0003 port d data register (ptd) r: ptd7 ptd6 ptd5 ptd4 ptd3 ptd2 ptd1 ptd0 w: $0004 data direction register a (ddra) r: ddra7 ddra6 ddra5 ddra4 ddra3 ddra2 ddra1 ddra0 w: $0005 data direction registerb (ddrb) r: ddrb7 ddrb6 ddrb5 ddrb4 ddrb3 ddrb2 ddrb1 ddrb0 w: $0006 data direction register c (ddrc) r: mclken 0 ddrc5 ddrc4 ddrc3 ddrc2 ddrc1 ddrc0 w: r $0007 data direction register d (ddrd) r: ddrd7 ddrd6 ddrd5 ddrd4 ddrd3 ddrd2 ddrd1 ddrd0 w: $0008 port e data register (pte) r: pte7 pte6 pte5 pte4 pte3 pte2 pte1 pte0 w: $0009 port f data register (ptf) r: 0 ptf6 ptf5 ptf4 ptf3 ptf2 ptf1 ptf0 w: r $000a port g data register (ptg) r: 0 0 0 0 0 ptg2 ptg1 ptg0 w: r r r r r $000b port h data register (pth) r: 0 0 0 0 0 0 pth1 pth0 w: r r r r r r $000c data direction register e (ddre) r: ddre7 ddre6 ddre5 ddre4 ddre3 ddre2 ddre1 ddre0 w: $000d data direction register f (ddrf) r: 0 ddrf6 ddrf5 ddrf4 ddrf3 ddrf2 ddrf1 ddrf0 w: r $000e data direction register g (ddrg) r: 0 0 0 0 0 ddrg2 ddrg1 ddrg0 w: r r r r r $000f data direction register (ddrh) r: 0 0 0 0 0 0 ddrh1 ddrh0 w: r r r r r r $0010 spi control register (spcr) r: sprie r sp- mstr cpol cpha spwom spe sptie w: $0011 spi status and control register (spscr) r: sprf errie ovrf modf spte modfen spr1 spr0 w: $0012 spi data register (spdr) r: r7 r6 r5 r4 r3 r2 r1 r0 w: t7 t6 t5 t4 t3 t2 t1 t0 $0013 sci control register 1 (scc1) r: loops ensci txinv m wake ilty pen pty w: = unimplemented r = reserved figure 2-2. i/o data, status and control registers (sheet 1 of 4) memory map technical data MC68HC08AZ32A ? rev 1.0 46 memory map motorola $0014 sci control register 2 (scc2) r: sctie tcie scrie ilie te re rwu sbk w: $0015 sci control register 3 (scc3) r: r8 t8 r r orie neie feie peie w: $0016 sci status register 1 (scs1) r: scte tc scrf idle or nf fe pe w: $0017 sci status register 2 (scs2) r: 0 0 0 0 0 0 bkf rpf w: $0018 sci data register (scdr) r: r7 r6 r5 r4 r3 r2 r1 r0 w: t7 t6 t5 t4 t3 t2 t1 t0 $0019 sci baud rate register (scbr) r: 0 0 scp1 scp0 r scr2 scr1 scr0 w: $001a irq status and control register (iscr) r: 0 0 0 0 irqf 0 imask mode w: r r r r r ack $001b keyboard status/control (kbscr) r: 0 0 0 0 keyf 0 imaskk modek w: ackk $001c pll control register (pctl) r: pllie pllf pllon bcs 1111 w: $001d pll bandwidth control register (pbwc) r: auto lock acq xld 0000 w: $001e pll programming register (ppg) r: mul7 mul6 mul5 mul4 vrs7 vrs6 vrs5 vrs4 w: $001f mask option register a (mora) r: lvistop romsec lvirst lvipwr ssrec coprs stop copd w: r r r r r r r r $0020 timer a status and control register (tasc) r: tof toie tstop 0 0 ps2 ps1 ps0 w: 0 trst r $0021 keyboard interrupt enable register (kbier) r; 0 0 0 kbie4 kbie3 kbie2 kbie1 kbie0 w: $0022 timer a counter register high (tacnth) r: bit 15 14 13 12 11 10 9 bit 8 w; r r r r r r r r $0023 timer a counter register low (tacntl) r:bit 76 5 4 3 2 1bit 0 w: r r r r r r r r $0024 timer a modulo register high (tamodh) r: bit 15 14 13 12 11 10 9 bit 8 w: $0025 timer a modulo register low (tamodl) r: bit 76 5 4 3 2 1bit 0 w: $0026 timer a channel 0 status and control register (tasc0) r: ch0f ch0ie ms0b ms0a els0b els0a tov0 ch0max w: 0 $0027 timer a channel 0 register high (tach0h) r: bit 15 14 13 12 11 10 9 bit 8 w: $0028 timer a channel 0 register low (tach0l) r: bit 76 5 4 3 2 1bit 0 w: $0029 timer a channel 1 status and control register (tasc1) r: ch1f ch1ie 0 ms1a els1b els1a tov1 ch1max w: 0 r $002a timer a channel 1 register high (tach1h) r: bit 15 14 13 12 11 10 9 bit 8 w: addr. name bit 76 5 4 3 2 1bit 0 = unimplemented r = reserved figure 2-2. i/o data, status and control registers (sheet 2 of 4) memory map i/o section MC68HC08AZ32A ? rev 1.0 technical data motorola memory map 47 $002b timer a channel 1 register low (tach1l) r: bit 76 5 4 3 2 1bit 0 w: $002c timer a channel 2 status and control register (tasc2) r: ch2f ch2ie ms2b ms2a els2b els2a tov2 ch2max w: 0 $002d timer a channel 2 register high (tach2h) r: bit 15 14 13 12 11 10 9 bit 8 w: $002e timer a channel 2 register low (tach2l) r: bit 76 5 4 3 2 1bit 0 w: $002f timer a channel 3 status and control register (tasc3) r: ch3f ch3ie 0 ms3a els3b els3a tov3 ch3max w: 0 r $0030 timer a channel 3 register high (tach3h) r: bit 15 14 13 12 11 10 9 bit 8 w: $0031 timer a channel 3 register low (tach3l) r: bit 76 5 4 3 2 1bit 0 w: $0032 timer a channel 4 status and control register (tasc4) r: ch4f ch4ie ms4b ms4a els4b els4a tov4 ch4max w: 0 $0033 timer a channel 4 register high (tach4h) r: bit 15 14 13 12 11 10 9 bit 8 w: $0034 timer a channel 4 register low (tach4l) r: bit 76 5 4 3 2 1bit 0 w: $0035 timer a channel 5 status and control register (tasc5) r: ch5f ch5ie 0 ms5a els5b els5a tov5 ch5max w: 0 r $0036 timer a channel 5 register high (tach5h) r: bit 15 14 13 12 11 10 9 bit 8 w: $0037 timer a channel 5 register low (tach5l) r: bit 76 5 4 3 2 1bit 0 w: $0038 adscr r: coco aien adco adch4 adch3 adch2 adch1 adch0 w: r $0039 adr r: ad7 ad6 ad5 ad4 ad3 ad2 ad1 ad0 w: r r r r r r r r $003a adc input clock register (adiclk) r: adiv2 adiv1 adiv0 adiclk 0000 w: r r r r $003b unimplemented r: w: $003c unimplemented r: w: $003d unimplemented r: w: $003e unimplemented r: w: $0040 timer b status and control register (tbsc) r: tof toie tstop 00 ps2 ps1 ps0 w: 0 trst r $0041 timer b counter register high (tbcnth) r: bit 15 14 13 12 11 10 9 8 w: r r r r r r r r $0042 timer b counter register low (tbcntl) r: bit 7 6 5 4 3 2 1 0 w: r r r r r r r r addr. name bit 76 5 4 3 2 1bit 0 = unimplemented r = reserved figure 2-2. i/o data, status and control registers (sheet 3 of 4) memory map technical data MC68HC08AZ32A ? rev 1.0 48 memory map motorola $0043 timer b modulo register high (tbmodh) r: bit 15 14 13 12 11 10 9 bit 8 w: $0044 timer b modulo register low (tbmodl) r: bit 76 5 4 3 2 1bit 0 w: $0045 timer b channel 0status and control register (tbsc0) r: ch0f ch0ie ms0b ms0a els0b els0a tov0 ch0max w: 0 $0046 timer b channel 0register high (tbch0h) r: bit 15 14 13 12 11 10 9 8 w: $0047 timer b channel 0register low (tbch0l) r: bit 7 6 5 4 3 2 1 0 w: $0048 timer b channel 1status/ control register (tbsc1) r: ch1f ch1ie 0 ms1a els1b els1a tov1 ch1max w: 0r $0049 timer b channel 1register high (tbch1h) r: bit 15 14 13 12 11 10 9 8 w: $004a timer b channel1register low (tbch1l) r: bit 7 6 5 4 3 2 1 0 w: $004b pit status & control register (psc) r: pof poie pstop 0 0 pps2 pps1 pps0 w: 0 prst $004c pit counter register high) (pcnth) r: bit 15 14 13 12 11 10 9 bit 8 w: $004d pit counter register low (pcntl) r:bit 76 5 4 3 2 1bit 0 w: $004e pit modulo register high (pmodh) r: bit 15 14 13 12 11 10 9 8 w: $004f pit modulo register low (pmodl) r: 7 6 5 4 3 2 1 0 w: addr. name bit 76 5 4 3 2 1bit 0 = unimplemented r = reserved figure 2-2. i/o data, status and control registers (sheet 4 of 4) memory map additional status and control registers MC68HC08AZ32A ? rev 1.0 technical data motorola memory map 49 2.4 additional status and control registers selected addresses in the range $fe00 to $ffcb contain additional status and control registers as shown in figure 2-3 . a noted exception is the cop control register (copctl) at address $ffff. addr. name bit 76 5 4 3 2 1bit 0 $fe00 sim break status register (sbsr) r: rr r r r r bw r w: 0 $fe01 sim reset status register (srsr) r: por pin cop ilop ilad 0 lvi 0 w: $fe03 sim break flag control register (sbfcr) r: bcfe r r r r r r r w: $fe09 mask option register b (morb) r: eedivcl k r eesec eemonse c az32a rrr w: r r r r $fe0c break address register high (brkh) r: bit 15 14 13 12 11 10 9 8 w: $fe0d break address register low (brkl) r: 7 6 5 4 3 2 1 0 w: $fe0e break status and control register (brkscr) r: brke brka 000000 w: $fe0f lvi status register (lvisr) r: lviout 0 0 0 0 0 0 0 w: $fe10 eediv high non-volatile register (eedivhnvr) r: w: eediv secd r r r r eediv10 eediv9 eediv8 $fe11 eediv low non-volatile register (eedivlnvr) r: w: eediv7 eediv6 eediv5 eediv4 eediv3 ee2div eediv1 eediv0 $fe1a eediv divider high register (eedivh) r: w: eediv secd 00 0 0 eediv10 eediv9 eediv8 $fe1b eediv divider low register (eedivl) r: w: eediv7 eediv6 eediv5 eediv4 eediv3 ee2div eediv1 eediv0 $fe1c eenvr r: r r r eeprtct eepb3 eepb2 eepb1 eepb0 w: $fe1d eecr r: r 0 eeoff eeras1 eeras0 elat auto eepgm w: $fe1f eeacr r: r r r eeprtct eebp3 eebp2 eebp1 eebp0 w: $ffff cop control register (copctl) r: low byte of reset vector w: writing to $ffff clears cop counter = unimplemented r = reserved figure 2-3. additional status and control registers memory map technical data MC68HC08AZ32A ? rev 1.0 50 memory map motorola 2.5 vector addresses and priority addresses in the range $ffcc to $ffff contain the user-specified vector locations. the vector addresses are shown in table 2-1 . table 2-1. vector addresses (1) address vector lowest priority $ffcc tima channel 5 vector (high) $ffcd tima channel 5 vector (low) $ffce tima channel 4 vector (high) $ffcf tima channel 4 vector (low) $ffd0 adc vector (high) $ffd1 adc vector (low) $ffd2 keyboard vector (high) $ffd3 keyboard vector (low) $ffd4 sci transmit vector (high) $ffd5 sci transmit vector (low) $ffd6 sci receive vector (high) $ffd7 sci receive vector (low) $ffd8 sci error vector (high) $ffd9 sci error vector (low) $ffda mscan08 transmit vector (high) $ffdb mscan08 transmit vector (low) $ffdc mscan08 receive vector (high) $ffdd mscan08 receive vector (low) $ffde mscan08 error vector (high) $ffdf mscan08 error vector (low) $ffe0 mscan08 wakeup vector (high) $ffe1 mscan08 wakeup vector (low) priority memory map technical data MC68HC08AZ32A ? rev 1.0 51 memory map motorola $ffe2 spi transmit vector (high) $ffe3 spi transmit vector (low) $ffe4 spi receive vector (high) $ffe5 spi receive vector (low) $ffe6 timb overflow vector (high) $ffe7 timb overflow vector (low) $ffe8 timb ch1 vector (high) $ffe9 timb ch1 vector (low) $ffea timb ch0 vector (high) $ffeb timb ch0 vector (low) $ffec tima overflow vector (high) $ffed tima overflow vector (low) $ffee tima ch3 vector (high) $ffef tima ch3 vector (low) $fff0 tima ch2 vector (high) $fff1 tima ch2 vector (low) $fff2 tima ch1 vector (high) $fff3 tima ch1 vector (low) $fff4 tima ch0 vector (high) $fff5 tima ch0 vector (low) $fff6 pit vector (high) $fff7 pit vector (low) $fff8 pll vector (high) $fff9 pll vector (low) $fffa irq vector (high) $fffb irq vector (low) $fffc swi vector (high) $fffd swi vector (low) $fffe reset vector (high) highest priority $ffff reset vector (low) 1. all available rom locations not defined by the user will by default be filled with the software interrupt (swi, opcode 83) instruction ? see central processor unit (cpu) . take this into account when defining vector addresses. it is recommended that all vector addresses are defined. table 2-1. vector addresses (continued) (1) address vector priority memory map technical data MC68HC08AZ32A ? rev 1.0 52 memory map motorola MC68HC08AZ32A ? rev 1.0 technical data motorola ram 53 technical data ? MC68HC08AZ32A section 3. ram 3.1 contents 3.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3.3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3.2 introduction this section describes the 1024 bytes of ram. 3.3 functional description addresses $0050 through $044f are ram locations. the location of the stack ram is programmable. the 16-bit stack pointer allows the stack to be anywhere in the 64k byte memory space. note: for correct operation, the stack pointer must point only to ram locations. within page zero there are 176 bytes of ram. because the location of the stack ram is programmable, all page zero ram locations can be used for i/o control and user data or code. when the stack pointer is moved from its reset location at $00ff, direct addressing mode instructions can efficiently access all page zero ram locations. page zero ram, therefore, provides an ideal location for frequently accessed global variables. before processing an interrupt, the cpu uses 5 bytes of the stack to save the contents of the cpu registers. note: for m6805 compatibility, the h register is not stacked. ram technical data MC68HC08AZ32A ? rev 1.0 54 ram motorola during a subroutine call, the cpu uses 2 bytes of the stack to store the return address. the stack pointer decrements during pushes and increments during pulls. note: care should be taken when using nested subroutines. the cpu may overwrite data in the ram during a subroutine or during the interrupt stacking operation. MC68HC08AZ32A ? rev 1.0 technical data motorola rom 55 technical data ? MC68HC08AZ32A section 4. rom 4.1 contents 4.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.4 security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.2 introduction this section describes the operation of the embedded rom memory. 4.3 functional description the user rom consists of up to 32, 256 bytes from addresses $8000 ? $fdff. the monitor rom and vectors are located from $fe20 ? $ff5f. fifty-two user vectors, $ffcc ? $ffff, are dedicated to user-defined reset and interrupt vectors. 4.4 security security has been incorporated into the MC68HC08AZ32A to prevent external viewing of the rom contents (1) . this feature is selected by a mask option and ensures that customer-developed software remains propriety. see mask options on page 145. 1. no security feature is absolutely secure. however, motorola ? s strategy is to make reading or copying the rom difficult for unauthorized users. rom technical data MC68HC08AZ32A ? rev 1.0 56 rom motorola MC68HC08AZ32A ? rev 1.0 technical data motorola eeprom 57 technical data ? MC68HC08AZ32A section 5. eeprom 5.1 contents 5.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 5.4 eeprom register summary . . . . . . . . . . . . . . . . . . . . . . . . . 59 5.5 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 5.5.1 eeprom configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 5.5.2 eeprom timebase requirements . . . . . . . . . . . . . . . . . . 60 5.5.3 eeprom program/erase protection . . . . . . . . . . . . . . . . 61 5.5.4 eeprom block protection . . . . . . . . . . . . . . . . . . . . . . . . 62 5.5.5 eeprom programming and erasing . . . . . . . . . . . . . . . . 62 5.6 eeprom register descriptions . . . . . . . . . . . . . . . . . . . . . . 67 5.6.1 eeprom control register . . . . . . . . . . . . . . . . . . . . . . . . . 67 5.6.2 eeprom array configuration register . . . . . . . . . . . . . . 69 5.6.3 eeprom nonvolatile register . . . . . . . . . . . . . . . . . . . . . 71 5.6.4 eeprom timebase divider register . . . . . . . . . . . . . . . . 72 5.6.5 eeprom timebase divider non-volatile register . . . . . 74 5.7 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 5.7.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 5.7.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 5.2 introduction this section describes the 512 bytes of electrically erasable programmable read-only memory (eeprom) residing at address range $0800 to $09ff. eeprom technical data MC68HC08AZ32A ? rev 1.0 58 eeprom motorola 5.3 features features of the eeprom include the following: 512 bytes non-volatile memory byte, block, or bulk erasable non-volatile eeprom configuration and block protection options on-chip charge pump for programming/erasing program/erase protection option read protection option auto bit driven programming/erasing time feature eeprom eeprom register summary MC68HC08AZ32A ? rev 1.0 technical data motorola eeprom 59 5.4 eeprom register summary the eeprom register summary is shown in figure 5-1 . addr.register name bit 7654321bit 0 $fe10 eediv non-volatile register high (eedivhnvr)* read: eedivsecd rrrreediv10eediv9eediv8 write: reset: unaffected by reset; $ff when blank $fe11 eediv non-volatile register low (eedivlnvr)* read: eediv7 eediv6 eediv5 eediv4 eediv3 eediv2 eediv1 eediv0 write: reset: unaffected by reset; $ff when blank $fe1a ee divider register high (eedivh) read: eedivsecd 0000 eediv10 eediv9 eediv8 write: reset: contents of eedivhnvr ($fe10), bits [6:3] = 0 $fe1b ee divider register low (eedivl) read: eediv7 eediv6 eediv5 eediv4 eediv3 eediv2 eediv1 eediv0 write: reset: contents of eedivlnvr ($fe11) $fe1c eeprom non-volatile register (eenvr)* read: unused unused unused eeprtct eebp3 eebp2 eebp1 eebp0 write: reset: unaffected by reset; $ff when blank; factory programmed $f0 $fe1d eeprom control register (eecr) read: unused 0 eeoff eeras1 eeras0 eelat auto eepgm write: reset:00000000 $fe1f eeprom array configuration register (eeacr) read: unused unused unused eeprtct eebp3 eebp2 eebp1 eebp0 write: reset: contents of eenvr ($fe1c) * non-volatile eeprom register; write by programming. = unimplemented r = reserved unused = unused figure 5-1. eeprom register summary eeprom technical data MC68HC08AZ32A ? rev 1.0 60 eeprom motorola 5.5 functional description the 512 bytes of eeprom are located at $0800-$09ff and can be programmed or erased without an additional external high voltage supply. the program and erase operations are enabled through the use of an internal charge pump. for each byte of eeprom, the write/erase endurance is 10,000 cycles. 5.5.1 eeprom configuration the 8-bit eeprom non-volatile register (eenvr) and the 16-bit eeprom timebase divider non-volatile register (eedivnvr) contain the default settings for the following eeprom configurations: eeprom timebase reference eeprom program/erase protection eeprom block protection eenvr and eedivnvr are non-volatile eeprom registers. they are programmed and erased in the same way as eeprom bytes. the contents of these registers are loaded into their respective volatile registers during a mcu reset. the values in these read/write volatile registers define the eeprom configurations. for eenvr, the corresponding volatile register is the eeprom array configuration register (eeacr). for the eedivnvr (two 8-bit registers: eedivhnvr and eedivlnvr), the corresponding volatile register is the eeprom divider register (eediv: eedivh and ee divl). 5.5.2 eeprom timebase requirements a 35 s timebase is required by the eeprom control circuit for program and erase of eeprom content. this timebase is derived from dividing the cgmxclk or bus clock (selected by eedivclk bit in mask option register b) using a timebase divider circuit controlled by the 16-bit eeprom timebase divider eediv register (eedivh and eedivl). eeprom functional description MC68HC08AZ32A ? rev 1.0 technical data motorola eeprom 61 as the cgmxclk or bus clock is user selected, the eeprom timebase divider register must be configured with the appropriate value to obtain the 35 s. the timebase divider value is calculated by using the following formula: eediv= int[reference frequency(hz) x 35 x10 -6 +0.5] this value is written to the eeprom timebase divider register (eedivh and eedivl) or programmed into the eeprom timebase divider non-volatile register prior to any eeprom program or erase operations(see eeprom configuration on page 60 and eeprom timebase requirements on page 60). 5.5.3 eeprom program/erase protection the eeprom has a special feature that designates the 16 bytes of addresses from $08f0 to $08ff to be permanently secured. this program/erase protect option is enabled by programming the eeprtct bit in the eeprom non-volatile register (eenvr) to a logic zero. once the eeprtct bit is programmed to 0 for the first time: programming and erasing of secured locations $08f0 to $08ff is permanently disabled. secured locations $08f0 to $08ff can be read as normal. programming and erasing of eenvr is permanently disabled. bulk and block erase operations are disabled for the unprotected locations $0800-$08ef, $0900-$09ff. single byte program and erase operations are still available for locations $0800-$08ef and $0900-$09ff for all bytes that are not protected by the eeprom block protect eebpx bits (see eeprom block protection on page 62 and eeprom array configuration register on page 69). note: once armed, the protect option is permanently enabled. as a consequence, all functions in the eenvr will remain in the state they were in immediately before the security was enabled. eeprom technical data MC68HC08AZ32A ? rev 1.0 62 eeprom motorola 5.5.4 eeprom block protection the 512 bytes of eeprom are divided into four 128-byte blocks. each of these blocks can be protected from erase/program operations by setting the eebpx bit in the eenvr. table 5-1 shows the address ranges for the blocks. these bits are effective after a reset or a upon read of the eenvr register. the block protect configuration can be modified by erasing/programming the corresponding bits in the eenvr register and then reading the eenvr register. please see eeprom array configuration register on page 69 for more information. note: once eedivsecd in the eedivhnvr is programmed to 0 and after a system reset, the eediv security feature is permanently enabled because the eedivsecd bit in the eedivh is always loaded with 0 thereafter. once this security feature is armed, erase and program mode are disabled for eedivhnvr and eedivlnvr. modifications to the eedivh and eedivl registers are also disabled. therefore, be cautious on programming a value into the eedivhnvr. 5.5.5 eeprom programming and erasing the unprogrammed or erase state of an eeprom bit is a logic 1. the factory default for all bytes within the eeprom array is $ff. the programming operation changes an eeprom bit from logic 1 to logic 0 (programming cannot change a bit from logic 0 to a logic 1). in a single programming operation, the minimum eeprom programming size is one bit; the maximum is eight bits (one byte). table 5-1. eeprom array address blocks block number (eebpx) address range eebp0 $0800 ? $087f eebp1 $0880 ? $08ff eebp2 $0900 ? $097f eebp3 $0980 ? $09ff eeprom functional description MC68HC08AZ32A ? rev 1.0 technical data motorola eeprom 63 the erase operation changes an eeprom bit from logic 0 to logic 1. in a single erase operation, the minimum eeprom erase size is one byte; the maximum is the entire eeprom array. the eeprom can be programmed such that one or multiple bits are programmed (written to a logic 0) at a time. however, the user may never program the same bit location more than once before erasing the entire byte. in other words, the user is not allowed to program a logic 0 to a bit that is already programmed (bit state is already logic 0). for some applications it might be advantageous to track more than 10k events with a single byte of eeprom by programming one bit at a time. for that purpose, a special selective bit programming technique is available. an example of this technique is illustrated in table 5-2 . note that none of the bit locations are actually programmed more than once although the byte was programmed eight times. when this technique is utilized, a program/erase cycle is defined as multiple program sequences (up to eight) to a unique location followed by a single erase operation. table 5-2. example selective bit programming description description program data in binary result in binary original state of byte (erased) n/a 1111:1111 first event is recorded by programming bit position 0 1111:1110 1111:1110 second event is recorded by programming bit position 1 1111:1101 1111:1100 third event is recorded by programming bit position 2 1111:1011 1111:1000 fourth event is recorded by programming bit position 3 1111:0111 1111:0000 events five through eight are recorded in a similar fashion eeprom technical data MC68HC08AZ32A ? rev 1.0 64 eeprom motorola 5.5.5.1 program/erase using auto bit an additional feature available for eeprom program and erase operations is the auto mode. when enabled, auto mode will activate an internal timer that will automatically terminate the program/erase cycle and clear the eepgm bit. please see eeprom programming on page 64, eeprom erasing on page 65 and eeprom control register on page 67 for more information. 5.5.5.2 eeprom programming the unprogrammed or erase state of an eeprom bit is a logic 1. programming changes the state to a logic 0. only eeprom bytes in the non-protected blocks and the eenvr register can be programmed. use the following procedure to program a byte of eeprom: 1. clear eeras1 and eeras0 and set eelat in the eecr. (a) note: if using the auto mode, also set the auto bit during step 1. 2. write the desired data to the desired eeprom address. (b) 3. set the eepgm bit. (c) go to step 7 if auto is set. 4. wait for time, t eepgm , to program the byte. 5. clear eepgm bit. 6. wait for time, t eefpv , for the programming voltage to fall. go to step 8. 7. poll the eepgm bit until it is cleared by the internal timer. (d) 8. clear eelat bits. (e) note: a. eeras1 and eeras0 must be cleared for programming. setting the eelat bit configures the address and data buses to latch data for programming the array. only data with a valid eeprom address will be latched. if eelat is set, other writes to the eecr will be allowed after a valid eeprom write. b. if more than one valid eeprom write occurs, the last address and data will be latched overriding the previous address and data. once data eeprom functional description MC68HC08AZ32A ? rev 1.0 technical data motorola eeprom 65 is written to the desired address, do not read eeprom locations other than the written location. (reading an eeprom location returns the latched data and causes the read address to be latched). c. the eepgm bit cannot be set if the eelat bit is cleared or a non- valid eeprom address is latched. this is to ensure proper programming sequence. once eepgm is set, do not read any eeprom locations; otherwise, the current program cycle will be unsuccessful. when eepgm is set, the on-board programming sequence will be activated. d. the delay time for the eepgm bit to be cleared in auto mode is less than t eepgm . however, on other mcus, this delay time may be different. for forward compatibility, software should not make any dependency on this delay time. e. any attempt to clear both eepgm and eelat bits with a single instruction will only clear eepgm. this is to allow time for removal of high voltage from the eeprom array. 5.5.5.3 eeprom erasing the programmed state of an eeprom bit is logic 0. erasing changes the state to a logic 1. only eeprom bytes in the non-protected blocks and the eenvr register can be erased. use the following procedure to erase a byte, block or the entire eeprom array: 1. configure eeras1 and eeras0 for byte, block or bulk erase; set eelat in eecr. (a) note: if using the auto mode, also set the auto bit in step 1. 2. byte erase: write any data to the desired address. (b) block erase: write any data to an address within the desired block. (b) bulk erase: write any data to an address within the array. (b) 3. set the eepgm bit. (c) go to step 7 if auto is set. eeprom technical data MC68HC08AZ32A ? rev 1.0 66 eeprom motorola 4. wait for a time: t eebyte for byte erase; t eeblock for block erase; t eebulk. for bulk erase. 5. clear eepgm bit. 6. wait for a time, t eefpv , for the erasing voltage to fall. go to step 8. 7. poll the eepgm bit until it is cleared by the internal timer. (d) 8. clear eelat bits. (e) note: a. setting the eelat bit configures the address and data buses to latch data for erasing the array. only valid eeprom addresses will be latched. if eelat is set, other writes to the eecr will be allowed after a valid eeprom write. b. if more than one valid eeprom write occurs, the last address and data will be latched overriding the previous address and data. once data is written to the desired address, do not read eeprom locations other than the written location. (reading an eeprom location returns the latched data and causes the read address to be latched). c. the eepgm bit cannot be set if the eelat bit is cleared or a non- valid eeprom address is latched. this is to ensure proper programming sequence. once eepgm is set, do not read any eeprom locations; otherwise, the current program cycle will be unsuccessful. when eepgm is set, the on-board programming sequence will be activated. d. the delay time for the eepgm bit to be cleared in auto mode is less than t eebyte /t eeblock /t eebulk . however, on other mcus, this delay time may be different. for forward compatibility, software should not make any dependency on this delay time. e. any attempt to clear both eepgm and eelat bits with a single instruction will only clear eepgm. this is to allow time for removal of high voltage from the eeprom array. eeprom eeprom register descriptions MC68HC08AZ32A ? rev 1.0 technical data motorola eeprom 67 5.6 eeprom register descriptions four i/o registers and three non-volatile registers control program, erase and options of the eeprom array. 5.6.1 eeprom control register this read/write register controls programming/erasing of the array. bit 7 ? unused bit this read/write bit is software programmable but has no functionality. eeoff ? eeprom power down this read/write bit disables the eeprom module for lower power consumption. any attempts to access the array will give unpredictable results. reset clears this bit. 1 = disable eeprom array 0 = enable eeprom array address: $fe1d bit 7654321bit 0 read: unused 0 eeoff eeras1 eeras0 eelat auto eepgm write: reset:00000000 = unimplemented figure 5-2. eeprom control register (eecr) eeprom technical data MC68HC08AZ32A ? rev 1.0 68 eeprom motorola eeras1 and eeras0 ? erase/program mode select bits these read/write bits set the erase modes. reset clears these bits. eelat ? eeprom latch control this read/write bit latches the address and data buses for programming the eeprom array. eelat cannot be cleared if eepgm is still set. reset clears this bit. 1 = buses configured for eeprom programming or erase operation 0 = buses configured for normal operation auto ? automatic termination of program/erase cycle when auto is set, eepgm is cleared automatically after the program/erase cycle is terminated by the internal timer. (see note d for eeprom programming on page 64, eeprom erasing on page 65 and eeprom memory characteristics on page 435) 1 = automatic clear of eepgm is enabled 0 = automatic clear of eepgm is disabled eepgm ? eeprom program/erase enable this read/write bit enables the internal charge pump and applies the programming/erasing voltage to the eeprom array if the eelat bit is set and a write to a valid eeprom location has occurred. reset clears the eepgm bit. 1 = eeprom programming/erasing power switched on 0 = eeprom programming/erasing power switched off table 5-3. eeprom program/erase mode select eebpx eeras1 eeras0 mode 000byte program 001byte erase 010block erase 0 1 1 bulk erase 1 x x no erase/program x = don ? t care eeprom eeprom register descriptions MC68HC08AZ32A ? rev 1.0 technical data motorola eeprom 69 note: writing logic 0s to both the eelat and eepgm bits with a single instruction will clear eepgm only to allow time for the removal of high voltage. 5.6.2 eeprom array configuration register the eeprom array configuration register configures eeprom security and eeprom block protection. this read-only register is loaded with the contents of the eeprom non- volatile register (eenvr) after a reset. bit 7:5 ? unused bits these read/write bits are software programmable but have no functionality. eeprtct ? eeprom protection bit the eeprtct bit is used to enable the security feature in the eeprom (see eeprom program/erase protection on page 61). 1 = eeprom security disabled 0 = eeprom security enabled this feature is a write-once feature. once the protection is enabled it may not be disabled. address: $fe1f bit 7 6 5 4 3 2 1 bit 0 read: unused unused unused eeprtct eebp3 eebp2 eebp1 eebp0 write: reset: contents of eenvr ($fe1c) figure 5-3. eeprom array configuration register (eeacr) eeprom technical data MC68HC08AZ32A ? rev 1.0 70 eeprom motorola eebp[3:0] ? eeprom block protection bits these bits prevent blocks of eeprom array from being programmed or erased. 1 = eeprom array block is protected 0 = eeprom array block is unprotected block number (eebpx) address range eebp0 t$0800 ? $087f eebp1 $0880 ? $08ff eebp2 $0900 ? $097f eebp3 $0980 ? $09ff table 5-4. eeprom block protect and security summary address range eebpx eeprtct = 1 eeprtct = 0 $0800 - $087f eebp0 = 0 byte programming available bulk, block and byte erasing available byte programming available only byte erasing available eebp0 = 1 protected protected $0880 - $08ef eebp1 = 0 byte programming available bulk, block and byte erasing available byte programming available only byte erasing available eebp1 = 1 protected protected $08f0 - $08ff eebp1 = 0 byte programming available bulk, block and byte erasing available secured (no programming or erasing) eebp1 = 1 protected $0900 - $097f eebp2 = 0 byte programming available bulk, block and byte erasing available byte programming available only byte erasing available eebp2 = 1 protected protected eeprom eeprom register descriptions MC68HC08AZ32A ? rev 1.0 technical data motorola eeprom 71 5.6.3 eeprom nonvolatile register the contents of this register is loaded into the eeprom array configuration register (eeacr) after a reset. this register is erased and programmed in the same way as an eeprom byte. (see eeprom control register on page 67 for individual bit descriptions). note: the eenvr will leave the factory programmed with $f0 such that the full array is available and unprotected. $0980 - $09ff eebp3 = 0 byte programming available bulk, block and byte available byte programming available only byte erasing available eebp3 = 1 protected protected table 5-4. eeprom block protect and security summary address range eebpx eeprtct = 1 eeprtct = 0 address: $fe1c bit 7 6 5 4 3 2 1 bit 0 read: unused unused unused eeprtct eebp3 eebp2 eebp1 eebp0 write: reset: pv = unimplemented pv = programmed value or 1 in the erased state. figure 5-4. eeprom nonvolatile register (eenvr) eeprom technical data MC68HC08AZ32A ? rev 1.0 72 eeprom motorola 5.6.4 eeprom timebase divider register the 16-bit eeprom timebase divider register consists of two 8-bit registers: eedivh and eedivl. the 11-bit value in this register is used to configure the timebase divider circuit to obtain the 35 s timebase for eeprom control. these two read/write registers are respectively loaded with the contents of the eeprom timebase divider on-volatile registers (eedivhnvr and eedivlnvr) after a reset. address: $fe1a bit 7 6 5 4 3 2 1 bit 0 read: eedivsecd 0000 eediv10 eediv9 eediv8 write: reset: contents of eedivhnvr ($fe10), bits [6:3] = 0 = unimplemented figure 5-5. eediv divider high register (eedivh) address: $fe1b bit 7 6 5 4 3 2 1 bit 0 read: eediv7 eediv6 eediv5 eediv4 eediv3 eediv2 eediv1 eediv0 write: reset: contents of eedivlnvr ($fe11) figure 5-6. eediv divider low register (eedivl) eeprom eeprom register descriptions MC68HC08AZ32A ? rev 1.0 technical data motorola eeprom 73 eedivsecd ? eeprom divider security disable this bit enables/disables the security feature of the eediv registers. when eediv security feature is enabled, the state of the registers eedivh and eedivl are locked (including eedivsecd bit). the eedivhnvr and eedivlnvr non-volatile memory registers are also protected from being erased/programmed. 1 = eediv security feature disabled 0 = eediv security feature enabled eediv[10:0] ? eeprom timebase prescaler these prescaler bits store the value of eediv which is used as the divisor to derive a timebase of 35 s from the selected reference clock source (cgmxclk or bus block in the config-2 register) for the eeprom related internal timer and circuits. eediv[10:0] bits are readable at any time. they are writable when eelat = 0 and eedivsecd = 1. the eediv value is calculated by the following formula: eediv= int[reference frequency(hz) x 35 x10 -6 +0.5] where the result inside the bracket is rounded down to the nearest integer value for example, if the reference frequency is 4.9152mhz, the eediv value is 172 note: programming/erasing the eeprom with an improper eediv value may result in data lost and reduce endurance of the eeprom device. eeprom technical data MC68HC08AZ32A ? rev 1.0 74 eeprom motorola 5.6.5 eeprom timebase divider non-volatile register the 16-bit eeprom timebase divider non-volatile register consists of two 8-bit registers: eedivhnvr and eedivlnvr. the contents of these two registers are respectively loaded into the eeprom timebase divider registers, eedivh and eedivl, after a reset. these two registers are erased and programmed in the same way as an eeprom byte. these two registers are protected from erase and program operations if the eedivsecd is set to logic 1 in the eedivh (see eeprom timebase divider register ) or programmed to a logic 1 in the eedivhnvr. note: once eedivsecd in the eedivhnvr is programmed to 0 and after a system reset, the eediv security feature is permanently enabled because the eedivsecd bit in the eedivh is always loaded with 0 address: $fe10 bit 7 6 5 4 3 2 1 bit 0 read: eedivsecd r r r r eediv10 eediv9 eediv8 write: reset: unaffected by reset; $ff when blank r=reserved figure 5-7. eeprom divider non-volatile register high (eedivhnvr)) address: $fe11 bit 7 6 5 4 3 2 1 bit 0 read: eediv7 eediv6 eediv5 eediv4 eediv3 eediv2 eediv1 eediv0 write: reset: unaffected by reset; $ff when blank figure 5-8. eeprom divider non-volatile register low (eedivlnvr) eeprom low-power modes MC68HC08AZ32A ? rev 1.0 technical data motorola eeprom 75 thereafter. once this security feature is armed, erase and program mode are disabled for eedivhnvr and eedivlnvr. modifications to the eedivh and eedivl registers are also disabled. therefore, care should be taken before programming a value into the eedivhnvr. 5.7 low-power modes the wait and stop instructions can put the mcu in low power- consumption standby modes. 5.7.1 wait mode the wait instruction does not affect the eeprom. it is possible to start the program or erase sequence on the eeprom and put the mcu in wait mode. 5.7.2 stop mode the stop instruction reduces the eeprom power consumption to a minimum. the stop instruction should not be executed while a programming or erasing sequence is in progress. if stop mode is entered while eelat and eepgm are set, the programming sequence will be stopped and the programming voltage to the eeprom array removed. the programming sequence will be restarted after leaving stop mode; access to the eeprom is only possible after the programming sequence has completed. if stop mode is entered while eelat and eepgm is cleared, the programming sequence will be terminated abruptly. in either case, the data integrity of the eeprom is not guaranteed. eeprom technical data MC68HC08AZ32A ? rev 1.0 76 eeprom motorola MC68HC08AZ32A ? rev 1.0 technical data motorola central processor unit (cpu) 77 technical data ? MC68HC08AZ32A section 6. central processor unit (cpu) 6.1 contents 6.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 6.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 6.4 cpu registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 6.4.1 accumulator (a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 6.4.2 index register (h:x) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 6.4.3 stack pointer (sp) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 6.4.4 program counter (pc) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 6.4.5 condition code register (ccr) . . . . . . . . . . . . . . . . . . . . 81 6.5 arithmetic/logic unit (alu) . . . . . . . . . . . . . . . . . . . . . . . . . . 83 6.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 6.7 cpu during break interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 84 6.8 instruction set summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 6.9 opcode map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 6.2 introduction this section describes the central processor unit (cpu8). the m68hc08 cpu is an enhanced and fully object-code-compatible version of the m68hc05 cpu. the cpu08 reference manual (motorola document number cpu08rm/ad) contains a description of the cpu instruction set, addressing modes, and architecture. central processor unit (cpu) technical data MC68HC08AZ32A ? rev 1.0 78 central processor unit (cpu) motorola 6.3 features features of the cpu include the following: full upward, object-code compatibility with m68hc05 family 16-bit stack pointer with stack manipulation instructions 16-bit index register with x-register manipulation instructions 8.4mhz cpu internal bus frequency 64k byte program/data memory space 16 addressing modes memory-to-memory data moves without using accumulator fast 8-bit by 8-bit multiply and 16-bit by 8-bit divide instructions enhanced binary-coded decimal (bcd) data handling low-power stop and wait modes 6.4 cpu registers figure 6-1 shows the five cpu registers. cpu registers are not part of the memory map. figure 6-1. cpu registers accumulator (a) index register (h:x) stack pointer (sp) program counter (pc) condition code register (ccr) carry/borrow flag zero flag negative flag interrupt mask half-carry flag two ? s complement overflow flag v11h i nzc h x 0 0 0 0 7 15 15 15 70 central processor unit (cpu) cpu registers MC68HC08AZ32A ? rev 1.0 technical data motorola central processor unit (cpu) 79 6.4.1 accumulator (a) the accumulator is a general-purpose 8-bit register. the cpu uses the accumulator to hold operands and the results of arithmetic/logic operations. 6.4.2 index register (h:x) the 16-bit index register allows indexed addressing of a 64k byte memory space. h is the upper byte of the index register and x is the lower byte. h:x is the concatenated 16-bit index register. in the indexed addressing modes, the cpu uses the contents of the index register to determine the conditional address of the operand. the index register can also be used as a temporary data storage location. bit 7654321bit 0 a read: write: reset: unaffected by reset figure 6-2. accumulator (a) bit 151413121110987654321 bit 0 h:x read: write: reset:00000000 xxxxxxxx x = indeterminate figure 6-3. index register (h:x) central processor unit (cpu) technical data MC68HC08AZ32A ? rev 1.0 80 central processor unit (cpu) motorola 6.4.3 stack pointer (sp) the stack pointer is a 16-bit register that contains the address of the next location on the stack. during a reset, the stack pointer is preset to $00ff. the reset stack pointer (rsp) instruction sets the least significant byte to $ff and does not affect the most significant byte. the stack pointer decrements as data is pushed onto the stack and increments as data is pulled from the stack. in the stack pointer 8-bit offset and 16-bit offset addressing modes, the stack pointer can function as an index register to access data on the stack. the cpu uses the contents of the stack pointer to determine the conditional address of the operand. note: the location of the stack is arbitrary and may be relocated anywhere in ram. moving the sp out of page zero ($0000 to $00ff) frees direct address (page zero) space. for correct operation, the stack pointer must point only to ram locations. 6.4.4 program counter (pc) the program counter is a 16-bit register that contains the address of the next instruction or operand to be fetched. normally, the program counter automatically increments to the next sequential memory location every time an instruction or operand is fetched. jump, branch, and interrupt operations load the program counter with an address other than that of the next sequential location. bit 151413121110987654321 bit 0 sp read: write: reset:0000000011111111 figure 6-4. stack pointer (sp) central processor unit (cpu) cpu registers MC68HC08AZ32A ? rev 1.0 technical data motorola central processor unit (cpu) 81 during reset, the program counter is loaded with the reset vector address located at $fffe and $ffff. the vector address is the address of the first instruction to be executed after exiting the reset state. 6.4.5 condition code register (ccr) the 8-bit condition code register contains the interrupt mask and five flags that indicate the results of the instruction just executed. bits 6 and 5 are set permanently to ? 1 ? . the following paragraphs describe the functions of the condition code register. v ? overflow flag the cpu sets the overflow flag when a two's complement overflow occurs. the signed branch instructions bgt, bge, ble, and blt use the overflow flag. 1 = overflow 0 = no overflow bit 151413121110987654321 bit 0 pc read: write: reset: loaded with vector from $fffe and $ffff figure 6-5. program counter (pc) bit 7654321bit 0 ccr read: v11h i nzc write: reset:x11x1xxx x = indeterminate figure 6-6. condition code register (ccr) central processor unit (cpu) technical data MC68HC08AZ32A ? rev 1.0 82 central processor unit (cpu) motorola h ? half-carry flag the cpu sets the half-carry flag when a carry occurs between accumulator bits 3 and 4 during an add or adc operation. the half- carry flag is required for binary-coded decimal (bcd) arithmetic operations. the daa instruction uses the states of the h and c flags to determine the appropriate correction factor. 1 = carry between bits 3 and 4 0 = no carry between bits 3 and 4 i ? interrupt mask when the interrupt mask is set, all maskable cpu interrupts are disabled. cpu interrupts are enabled when the interrupt mask is cleared. when a cpu interrupt occurs, the interrupt mask is set automatically after the cpu registers are saved on the stack, but before the interrupt vector is fetched. 1 = interrupts disabled 0 = interrupts enabled note: to maintain m6805 compatibility, the upper byte of the index register (h) is not stacked automatically. if the interrupt service routine modifies h, then the user must stack and unstack h using the pshh and pulh instructions. after the i bit is cleared, the highest-priority interrupt request is serviced first. a return from interrupt (rti) instruction pulls the cpu registers from the stack and restores the interrupt mask from the stack. after any reset, the interrupt mask is set and can only be cleared by the clear interrupt mask software instruction (cli). central processor unit (cpu) arithmetic/logic unit (alu) MC68HC08AZ32A ? rev 1.0 technical data motorola central processor unit (cpu) 83 n ? negative flag the cpu sets the negative flag when an arithmetic operation, logic operation, or data manipulation produces a negative result, setting bit 7 of the result. 1 = negative result 0 = non-negative result z ? zero flag the cpu sets the zero flag when an arithmetic operation, logic operation, or data manipulation produces a result of $00. 1 = zero result 0 = non-zero result c ? carry/borrow flag the cpu sets the carry/borrow flag when an addition operation produces a carry out of bit 7 of the accumulator or when a subtraction operation requires a borrow. some instructions - such as bit test and branch, shift, and rotate - also clear or set the carry/borrow flag. 1 = carry out of bit 7 0 = no carry out of bit 7 6.5 arithmetic/logic unit (alu) the alu performs the arithmetic and logic operations defined by the instruction set. refer to the cpu08 reference manual (motorola document number cpu08rm/ad) for a description of the instructions and addressing modes and more detail about cpu architecture. central processor unit (cpu) technical data MC68HC08AZ32A ? rev 1.0 84 central processor unit (cpu) motorola 6.6 low-power modes the wait and stop instructions put the mcu in low--power consumption standby modes. 6.6.1 wait mode the wait instruction: clears the interrupt mask (i bit) in the condition code register, enabling interrupts. after exit from wait mode by interrupt, the i bit remains clear. after exit by reset, the i bit is set. disables the cpu clock 6.6.2 stop mode the stop instruction: clears the interrupt mask (i bit) in the condition code register, enabling external interrupts. after exit from stop mode by external interrupt, the i bit remains clear. after exit by reset, the i bit is set. disables the cpu clock after exiting stop mode, the cpu clock begins running after the oscillator stabilization delay. 6.7 cpu during break interrupts if the break module is enabled, a break interrupt causes the cpu to execute the software interrupt instruction (swi) at the completion of the current cpu instruction. see break module on page 149. the program counter vectors to $fffc ? $fffd ($fefc ? $fefd in monitor mode). a return from interrupt instruction (rti) in the break routine ends the break interrupt and returns the mcu to normal operation if the break interrupt has been deasserted. central processor unit (cpu) instruction set summary MC68HC08AZ32A ? rev 1.0 technical data motorola central processor unit (cpu) 85 6.8 instruction set summary table 6-1 provides a summary of the m68hc08 instruction set. table 6-1. instruction set summary source form operation description effect on ccr address mode opcode operand cycles vhi nzc adc # opr adc opr adc opr adc opr ,x adc opr ,x adc ,x adc opr ,sp adc opr ,sp add with carry a (a) + (m) + (c) ?? ? ??? imm dir ext ix2 ix1 ix sp1 sp2 a9 b9 c9 d9 e9 f9 9e e9 9e d9 ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 add # opr add opr add opr add opr ,x add opr ,x add ,x add opr ,sp add opr ,sp add without carry a (a) + (m) ?? ? ??? imm dir ext ix2 ix1 ix sp1 sp2 ab bb cb db eb fb 9e eb 9e db ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 ais # opr add immediate value (signed) to sp sp (sp) + (16 ? m) ?????? imm a7 ii 2 aix # opr add immediate value (signed) to h:x h:x (h:x) + (16 ? m) ?????? imm af ii 2 and # opr and opr and opr and opr ,x and opr ,x and ,x and opr ,sp and opr ,sp logical and a (a) & (m) 0 ?? ?? ? imm dir ext ix2 ix1 ix sp1 sp2 a4 b4 c4 d4 e4 f4 9e e4 9e d4 ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 asl opr asla aslx asl opr ,x asl ,x asl opr ,sp arithmetic shift left (same as lsl) ? ?? ??? dir inh inh ix1 ix sp1 38 48 58 68 78 9e 68 dd ff ff 4 1 1 4 3 5 asr opr asra asrx asr opr ,x asr opr ,x asr opr ,sp arithmetic shift right ? ?? ??? dir inh inh ix1 ix sp1 37 47 57 67 77 9e 67 dd ff ff 4 1 1 4 3 5 c b0 b7 0 b0 b7 c central processor unit (cpu) technical data MC68HC08AZ32A ? rev 1.0 86 central processor unit (cpu) motorola bcc rel branch if carry bit clear pc (pc) + 2 + rel ? (c) = 0 ?????? rel 24 rr 3 bclr n , opr clear bit n in m mn 0 ?????? dir (b0) dir (b1) dir (b2) dir (b3) dir (b4) dir (b5) dir (b6) dir (b7) 11 13 15 17 19 1b 1d 1f dd dd dd dd dd dd dd dd 4 4 4 4 4 4 4 4 bcs rel branch if carry bit set (same as blo) pc (pc) + 2 + rel ? (c) = 1 ?????? rel 25 rr 3 beq rel branch if equal pc (pc) + 2 + rel ? (z) = 1 ?????? rel 27 rr 3 bge opr branch if greater than or equal to (signed operands) pc (pc) + 2 + rel ? (n v ) = 0 ?????? rel 90 rr 3 bgt opr branch if greater than (signed operands) pc (pc) + 2 + rel ? (z) | (n v ) = 0 ?????? rel 92 rr 3 bhcc rel branch if half carry bit clear pc (pc) + 2 + rel ? (h) = 0 ?????? rel 28 rr 3 bhcs rel branch if half carry bit set pc (pc) + 2 + rel ? (h) = 1 ?????? rel 29 rr 3 bhi rel branch if higher pc (pc) + 2 + rel ? (c) | (z) = 0 ?????? rel 22 rr 3 bhs rel branch if higher or same (same as bcc) pc (pc) + 2 + rel ? (c) = 0 ?????? rel 24 rr 3 bih rel branch if irq pin high pc (pc) + 2 + rel ? irq = 1 ?????? rel 2f rr 3 bil rel branch if irq pin low pc (pc) + 2 + rel ? irq = 0 ?????? rel 2e rr 3 bit # opr bit opr bit opr bit opr ,x bit opr ,x bit ,x bit opr ,sp bit opr ,sp bit test (a) & (m) 0 ?? ?? ? imm dir ext ix2 ix1 ix sp1 sp2 a5 b5 c5 d5 e5 f5 9e e5 9e d5 ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 ble opr branch if less than or equal to (signed operands) pc (pc) + 2 + rel ? (z) | (n v ) = 1 ?????? rel 93 rr 3 blo rel branch if lower (same as bcs) pc (pc) + 2 + rel ? (c) = 1 ?????? rel 25 rr 3 bls rel branch if lower or same pc (pc) + 2 + rel ? (c) | (z) = 1 ?????? rel 23 rr 3 blt opr branch if less than (signed operands) pc (pc) + 2 + rel ? (n v ) = 1 ?????? rel 91 rr 3 table 6-1. instruction set summary (continued) source form operation description effect on ccr address mode opcode operand cycles vhi nzc central processor unit (cpu) instruction set summary MC68HC08AZ32A ? rev 1.0 technical data motorola central processor unit (cpu) 87 bmc rel branch if interrupt mask clear pc (pc) + 2 + rel ? (i) = 0 ?????? rel 2c rr 3 bmi rel branch if minus pc (pc) + 2 + rel ? (n) = 1 ?????? rel 2b rr 3 bms rel branch if interrupt mask set pc (pc) + 2 + rel ? (i) = 1 ?????? rel 2d rr 3 bne rel branch if not equal pc (pc) + 2 + rel ? (z) = 0 ?????? rel 26 rr 3 bpl rel branch if plus pc (pc) + 2 + rel ? (n) = 0 ?????? rel 2a rr 3 bra rel branch always pc (pc) + 2 + rel ?????? rel 20 rr 3 brclr n , opr , rel branch if bit n in m clear pc (pc) + 3 + rel ? (mn) = 0 ????? ? dir (b0) dir (b1) dir (b2) dir (b3) dir (b4) dir (b5) dir (b6) dir (b7) 01 03 05 07 09 0b 0d 0f dd rr dd rr dd rr dd rr dd rr dd rr dd rr dd rr 5 5 5 5 5 5 5 5 brn rel branch never pc (pc) + 2 ?????? rel 21 rr 3 brset n , opr , rel branch if bit n in m set pc (pc) + 3 + rel ? (mn) = 1 ????? ? dir (b0) dir (b1) dir (b2) dir (b3) dir (b4) dir (b5) dir (b6) dir (b7) 00 02 04 06 08 0a 0c 0e dd rr dd rr dd rr dd rr dd rr dd rr dd rr dd rr 5 5 5 5 5 5 5 5 bset n , opr set bit n in m mn 1 ?????? dir (b0) dir (b1) dir (b2) dir (b3) dir (b4) dir (b5) dir (b6) dir (b7) 10 12 14 16 18 1a 1c 1e dd dd dd dd dd dd dd dd 4 4 4 4 4 4 4 4 table 6-1. instruction set summary (continued) source form operation description effect on ccr address mode opcode operand cycles vhi nzc central processor unit (cpu) technical data MC68HC08AZ32A ? rev 1.0 88 central processor unit (cpu) motorola bsr rel branch to subroutine pc (pc) + 2; push (pcl) sp (sp) ? 1; push (pch) sp (sp) ? 1 pc (pc) + rel ?????? rel ad rr 4 cbeq opr,rel cbeqa # opr,rel cbeqx # opr,rel cbeq opr, x+ ,rel cbeq x+ ,rel cbeq opr, sp ,rel compare and branch if equal pc (pc) + 3 + rel ? (a) ? (m) = $00 pc (pc) + 3 + rel ? (a) ? (m) = $00 pc (pc) + 3 + rel ? (x) ? (m) = $00 pc (pc) + 3 + rel ? (a) ? (m) = $00 pc (pc) + 2 + rel ? (a) ? (m) = $00 pc (pc) + 4 + rel ? (a) ? (m) = $00 ?????? dir imm imm ix1+ ix+ sp1 31 41 51 61 71 9e 61 dd rr ii rr ii rr ff rr rr ff rr 5 4 4 5 4 6 clc clear carry bit c 0 ????? 0inh 98 1 cli clear interrupt mask i 0 ?? 0 ??? inh 9a 2 clr opr clra clrx clrh clr opr ,x clr ,x clr opr ,sp clear m $00 a $00 x $00 h $00 m $00 m $00 m $00 0 ?? 01 ? dir inh inh inh ix1 ix sp1 3f 4f 5f 8c 6f 7f 9e 6f dd ff ff 3 1 1 1 3 2 4 cmp # opr cmp opr cmp opr cmp opr ,x cmp opr ,x cmp ,x cmp opr ,sp cmp opr ,sp compare a with m (a) ? (m) ? ?? ??? imm dir ext ix2 ix1 ix sp1 sp2 a1 b1 c1 d1 e1 f1 9e e1 9e d1 ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 com opr coma comx com opr ,x com ,x com opr ,sp complement (one ? s complement) m (m ) = $ff ? (m) a (a ) = $ff ? (m) x (x ) = $ff ? (m) m (m ) = $ff ? (m) m (m ) = $ff ? (m) m (m ) = $ff ? (m) 0 ?? ?? 1 dir inh inh ix1 ix sp1 33 43 53 63 73 9e 63 dd ff ff 4 1 1 4 3 5 cphx # opr cphx opr compare h:x with m (h:x) ? (m:m + 1) ? ?? ??? imm dir 65 75 ii ii+1 dd 3 4 cpx # opr cpx opr cpx opr cpx ,x cpx opr ,x cpx opr ,x cpx opr ,sp cpx opr ,sp compare x with m (x) ? (m) ? ?? ??? imm dir ext ix2 ix1 ix sp1 sp2 a3 b3 c3 d3 e3 f3 9e e3 9e d3 ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 table 6-1. instruction set summary (continued) source form operation description effect on ccr address mode opcode operand cycles vhi nzc central processor unit (cpu) instruction set summary MC68HC08AZ32A ? rev 1.0 technical data motorola central processor unit (cpu) 89 daa decimal adjust a (a) 10 u ?? ??? inh 72 2 dbnz opr,rel dbnza rel dbnzx rel dbnz opr, x ,rel dbnz x ,rel dbnz opr, sp ,rel decrement and branch if not zero a (a) ? 1 or m (m) ? 1 or x (x) ? 1 pc (pc) + 3 + rel ? (result) 0 pc (pc) + 2 + rel ? (result) 0 pc (pc) + 2 + rel ? (result) 0 pc (pc) + 3 + rel ? (result) 0 pc (pc) + 2 + rel ? (result) 0 pc (pc) + 4 + rel ? (result) 0 ?????? dir inh inh ix1 ix sp1 3b 4b 5b 6b 7b 9e 6b dd rr rr rr ff rr rr ff rr 5 3 3 5 4 6 dec opr deca decx dec opr ,x dec ,x dec opr ,sp decrement m (m) ? 1 a (a) ? 1 x (x) ? 1 m (m) ? 1 m (m) ? 1 m (m) ? 1 ? ?? ?? ? dir inh inh ix1 ix sp1 3a 4a 5a 6a 7a 9e 6a dd ff ff 4 1 1 4 3 5 div divide a (h:a)/(x) h remainder ???? ?? inh 52 7 eor # opr eor opr eor opr eor opr ,x eor opr ,x eor ,x eor opr ,sp eor opr ,sp exclusive or m with a a (a m) 0 ?? ?? ? imm dir ext ix2 ix1 ix sp1 sp2 a8 b8 c8 d8 e8 f8 9e e8 9e d8 ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 inc opr inca incx inc opr ,x inc ,x inc opr ,sp increment m (m) + 1 a (a) + 1 x (x) + 1 m (m) + 1 m (m) + 1 m (m) + 1 ? ?? ?? ? dir inh inh ix1 ix sp1 3c 4c 5c 6c 7c 9e 6c dd ff ff 4 1 1 4 3 5 jmp opr jmp opr jmp opr ,x jmp opr ,x jmp ,x jump pc jump address ?????? dir ext ix2 ix1 ix bc cc dc ec fc dd hh ll ee ff ff 2 3 4 3 2 jsr opr jsr opr jsr opr ,x jsr opr ,x jsr ,x jump to subroutine pc (pc) + n ( n = 1, 2, or 3) push (pcl); sp (sp) ? 1 push (pch); sp (sp) ? 1 pc unconditional address ?????? dir ext ix2 ix1 ix bd cd dd ed fd dd hh ll ee ff ff 4 5 6 5 4 table 6-1. instruction set summary (continued) source form operation description effect on ccr address mode opcode operand cycles vhi nzc central processor unit (cpu) technical data MC68HC08AZ32A ? rev 1.0 90 central processor unit (cpu) motorola lda # opr lda opr lda opr lda opr ,x lda opr ,x lda ,x lda opr ,sp lda opr ,sp load a from m a (m) 0 ?? ?? ? imm dir ext ix2 ix1 ix sp1 sp2 a6 b6 c6 d6 e6 f6 9e e6 9e d6 ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 ldhx # opr ldhx opr load h:x from m h:x ( m:m + 1 ) 0 ?? ?? ? imm dir 45 55 ii jj dd 3 4 ldx # opr ldx opr ldx opr ldx opr ,x ldx opr ,x ldx ,x ldx opr ,sp ldx opr ,sp load x from m x (m) 0 ?? ?? ? imm dir ext ix2 ix1 ix sp1 sp2 ae be ce de ee fe 9e ee 9e de ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 lsl opr lsla lslx lsl opr ,x lsl ,x lsl opr ,sp logical shift left (same as asl) ? ?? ??? dir inh inh ix1 ix sp1 38 48 58 68 78 9e 68 dd ff ff 4 1 1 4 3 5 lsr opr lsra lsr x lsr opr ,x lsr ,x lsr opr ,sp logical shift right ? ?? 0 ?? dir inh inh ix1 ix sp1 34 44 54 64 74 9e 64 dd ff ff 4 1 1 4 3 5 mov opr,opr mov opr, x+ mov # opr,opr mov x+ ,opr move (m) destination (m) source h:x (h:x) + 1 (ix+d, dix+) 0 ?? ?? ? dd dix+ imd ix+d 4e 5e 6e 7e dd dd dd ii dd dd 5 4 4 4 mul unsigned multiply x:a (x) (a) ? 0 ??? 0inh 42 5 neg opr nega negx neg opr ,x neg ,x neg opr ,sp negate (two ? s complement) m ? (m) = $00 ? (m) a ? (a) = $00 ? (a) x ? (x) = $00 ? (x) m ? (m) = $00 ? (m) m ? (m) = $00 ? (m) ? ?? ??? dir inh inh ix1 ix sp1 30 40 50 60 70 9e 60 dd ff ff 4 1 1 4 3 5 nop no operation none ?????? inh 9d 1 nsa nibble swap a a (a[3:0]:a[7:4]) ?????? inh 62 3 table 6-1. instruction set summary (continued) source form operation description effect on ccr address mode opcode operand cycles vhi nzc c b0 b7 0 b0 b7 c 0 central processor unit (cpu) instruction set summary MC68HC08AZ32A ? rev 1.0 technical data motorola central processor unit (cpu) 91 ora # opr ora opr ora opr ora opr ,x ora opr ,x ora ,x ora opr ,sp ora opr ,sp inclusive or a and m a (a) | (m) 0 ?? ?? ? imm dir ext ix2 ix1 ix sp1 sp2 aa ba ca da ea fa 9e ea 9e da ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 psha push a onto stack push (a); sp (sp ) ? 1 ?????? inh 87 2 pshh push h onto stack push (h) ; sp (sp ) ? 1 ?????? inh 8b 2 pshx push x onto stack push (x) ; sp (sp ) ? 1 ?????? inh 89 2 pula pull a from stack sp (sp + 1); pull ( a ) ?????? inh 86 2 pulh pull h from stack sp (sp + 1); pull ( h ) ?????? inh 8a 2 pulx pull x from stack sp (sp + 1); pull ( x ) ?????? inh 88 2 rol opr rola rolx rol opr ,x rol ,x rol opr ,sp rotate left through carry ? ?? ??? dir inh inh ix1 ix sp1 39 49 59 69 79 9e 69 dd ff ff 4 1 1 4 3 5 ror opr rora rorx ror opr ,x ror ,x ror opr ,sp rotate right through carry ? ?? ??? dir inh inh ix1 ix sp1 36 46 56 66 76 9e 66 dd ff ff 4 1 1 4 3 5 rsp reset stack pointer sp $ff ?????? inh 9c 1 rti return from interrupt sp (sp) + 1; pull (ccr) sp (sp) + 1; pull (a) sp (sp) + 1; pull (x) sp (sp) + 1; pull (pch) sp (sp) + 1; pull (pcl) ?????? inh 80 7 rts return from subroutine sp sp + 1 ; pull ( pch) sp sp + 1; pull (pcl) ?????? inh 81 4 sbc # opr sbc opr sbc opr sbc opr ,x sbc opr ,x sbc ,x sbc opr ,sp sbc opr ,sp subtract with carry a (a) ? (m) ? (c) ? ?? ??? imm dir ext ix2 ix1 ix sp1 sp2 a2 b2 c2 d2 e2 f2 9e e2 9e d2 ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 sec set carry bit c 1 ????? 1inh 99 1 table 6-1. instruction set summary (continued) source form operation description effect on ccr address mode opcode operand cycles vhi nzc c b0 b7 b0 b7 c central processor unit (cpu) technical data MC68HC08AZ32A ? rev 1.0 92 central processor unit (cpu) motorola sei set interrupt mask i 1 ?? 1 ??? inh 9b 2 sta opr sta opr sta opr ,x sta opr ,x sta ,x sta opr ,sp sta opr ,sp store a in m m (a) 0 ?? ?? ? dir ext ix2 ix1 ix sp1 sp2 b7 c7 d7 e7 f7 9e e7 9e d7 dd hh ll ee ff ff ff ee ff 3 4 4 3 2 4 5 sthx opr store h:x in m (m:m + 1) (h:x) 0 ?? ?? ? dir 35 dd 4 stop enable irq pin; stop oscillator i 0; stop oscillator ?? 0 ??? inh 8e 1 stx opr stx opr stx opr ,x stx opr ,x stx ,x stx opr ,sp stx opr ,sp store x in m m (x) 0 ?? ?? ? dir ext ix2 ix1 ix sp1 sp2 bf cf df ef ff 9e ef 9e df dd hh ll ee ff ff ff ee ff 3 4 4 3 2 4 5 sub # opr sub opr sub opr sub opr ,x sub opr ,x sub ,x sub opr ,sp sub opr ,sp subtract a (a) ? (m) ? ?? ??? imm dir ext ix2 ix1 ix sp1 sp2 a0 b0 c0 d0 e0 f0 9e e0 9e d0 ii dd hh ll ee ff ff ff ee ff 2 3 4 4 3 2 4 5 swi software interrupt pc (pc) + 1; push (pcl) sp (sp) ? 1; push (pch) sp (sp) ? 1; push (x) sp (sp) ? 1; push (a) sp (sp) ? 1; push (ccr) sp (sp) ? 1; i 1 pch interrupt vector high byte pcl interrupt vector low byte ?? 1 ??? inh 83 9 tap transfer a to ccr ccr (a) ?????? inh 84 2 tax transfer a to x x (a) ?????? inh 97 1 tpa transfer ccr to a a (ccr) ?????? inh 85 1 tst opr tsta tstx tst opr ,x tst ,x tst opr ,sp test for negative or zero (a) ? $00 or (x) ? $00 or (m) ? $00 0 ?? ?? ? dir inh inh ix1 ix sp1 3d 4d 5d 6d 7d 9e 6d dd ff ff 3 1 1 3 2 4 tsx transfer sp to h:x h:x (sp) + 1 ?????? inh 95 2 table 6-1. instruction set summary (continued) source form operation description effect on ccr address mode opcode operand cycles vhi nzc central processor unit (cpu) opcode map MC68HC08AZ32A ? rev 1.0 technical data motorola central processor unit (cpu) 93 6.9 opcode map txa transfer x to a a (x) ?????? inh 9f 1 txs transfer h:x to sp (sp) (h:x) ? 1 ?????? inh 94 2 a accumulator n any bit c carry/borrow bit opr operand (one or two bytes) ccrcondition code registerpc program counter dddirect address of operandpch program counter high byte dd rrdirect address of operand and relative offset of branch instructionpcl program counter low byte dddirect to direct addressing moderel relative addressing mode dirdirect addressing mode rel relative program counter offset byte dix+direct to indexed with post increment addressing moderr relative program counter offset byte ee ffhigh and low bytes of offset in indexed, 16-bit offset addressingsp1 stack pointer, 8-bit offset addressing mode extextended addressing modesp2 stack pointer 16-bit offset addressing mode ff offset byte in indexed, 8-bit offset addressingsp stack pointer h half-carry bitu undefined h index register high bytev overflow bit hh llhigh and low bytes of operand address in extended addressingx index register low byte i interrupt maskz zero bit ii immediate operand byte& logical and imdimmediate source to direct destination addressing mode| logical or immimmediate addressing mode logical exclusive or inhinherent addressing mode( ) contents of ixindexed, no offset addressing mode ? ( ) negation (two ? s complement) ix+indexed, no offset, post increment addressing mode# immediate value ix+dindexed with post increment to direct addressing mode ? sign extend ix1indexed, 8-bit offset addressing mode loaded with ix1+indexed, 8-bit offset, post increment addressing mode? if ix2indexed, 16-bit offset addressing mode: concatenated with mmemory location ? set or cleared n negative bit ? not affected table 6-1. instruction set summary (continued) source form operation description effect on ccr address mode opcode operand cycles vhi nzc 1 technical data MC68HC08AZ32A ? rev 1.0 94 central processor unit (cpu) motorola central processor unit (cpu) bit manipulation branch read-modify-write control register/memory dir dir rel dir inh inh ix1 sp1 ix inh inh imm dir ext ix2 sp2 ix1 sp1 ix 0 12 3 4 5 69e67 8 9abcd9ede9eef 0 5 brset0 3dir 4 bset0 2dir 3 bra 2rel 4 neg 2dir 1 nega 1inh 1 negx 1inh 4 neg 2ix1 5 neg 3 sp1 3 neg 1ix 7 rti 1inh 3 bge 2rel 2 sub 2imm 3 sub 2dir 4 sub 3ext 4 sub 3ix2 5 sub 4 sp2 3 sub 2ix1 4 sub 3 sp1 2 sub 1ix 1 5 brclr0 3dir 4 bclr0 2dir 3 brn 2rel 5 cbeq 3dir 4 cbeqa 3imm 4 cbeqx 3imm 5 cbeq 3ix1+ 6 cbeq 4 sp1 4 cbeq 2ix+ 4 rts 1inh 3 blt 2rel 2 cmp 2imm 3 cmp 2dir 4 cmp 3ext 4 cmp 3ix2 5 cmp 4 sp2 3 cmp 2ix1 4 cmp 3 sp1 2 cmp 1ix 2 5 brset1 3dir 4 bset1 2dir 3 bhi 2rel 5 mul 1inh 7 div 1inh 3 nsa 1inh 2 daa 1inh 3 bgt 2rel 2 sbc 2imm 3 sbc 2dir 4 sbc 3ext 4 sbc 3ix2 5 sbc 4 sp2 3 sbc 2ix1 4 sbc 3 sp1 2 sbc 1ix 3 5 brclr1 3dir 4 bclr1 2dir 3 bls 2rel 4 com 2dir 1 coma 1inh 1 comx 1inh 4 com 2ix1 5 com 3 sp1 3 com 1ix 9 swi 1inh 3 ble 2rel 2 cpx 2imm 3 cpx 2dir 4 cpx 3ext 4 cpx 3ix2 5 cpx 4 sp2 3 cpx 2ix1 4 cpx 3 sp1 2 cpx 1ix 4 5 brset2 3dir 4 bset2 2dir 3 bcc 2rel 4 lsr 2dir 1 lsra 1inh 1 lsrx 1inh 4 lsr 2ix1 5 lsr 3 sp1 3 lsr 1ix 2 tap 1inh 2 txs 1inh 2 and 2imm 3 and 2dir 4 and 3ext 4 and 3ix2 5 and 4 sp2 3 and 2ix1 4 and 3 sp1 2 and 1ix 5 5 brclr2 3dir 4 bclr2 2dir 3 bcs 2rel 4 sthx 2dir 3 ldhx 3imm 4 ldhx 2dir 3 cphx 3imm 4 cphx 2dir 1 tpa 1inh 2 tsx 1inh 2 bit 2imm 3 bit 2dir 4 bit 3ext 4 bit 3ix2 5 bit 4 sp2 3 bit 2ix1 4 bit 3 sp1 2 bit 1ix 6 5 brset3 3dir 4 bset3 2dir 3 bne 2rel 4 ror 2dir 1 rora 1inh 1 rorx 1inh 4 ror 2ix1 5 ror 3 sp1 3 ror 1ix 2 pula 1inh 2 lda 2imm 3 lda 2dir 4 lda 3ext 4 lda 3ix2 5 lda 4 sp2 3 lda 2ix1 4 lda 3 sp1 2 lda 1ix 7 5 brclr3 3dir 4 bclr3 2dir 3 beq 2rel 4 asr 2dir 1 asra 1inh 1 asrx 1inh 4 asr 2ix1 5 asr 3 sp1 3 asr 1ix 2 psha 1inh 1 tax 1inh 2 ais 2imm 3 sta 2dir 4 sta 3ext 4 sta 3ix2 5 sta 4 sp2 3 sta 2ix1 4 sta 3 sp1 2 sta 1ix 8 5 brset4 3dir 4 bset4 2dir 3 bhcc 2rel 4 lsl 2dir 1 lsla 1inh 1 lslx 1inh 4 lsl 2ix1 5 lsl 3 sp1 3 lsl 1ix 2 pulx 1inh 1 clc 1inh 2 eor 2imm 3 eor 2dir 4 eor 3ext 4 eor 3ix2 5 eor 4 sp2 3 eor 2ix1 4 eor 3 sp1 2 eor 1ix 9 5 brclr4 3dir 4 bclr4 2dir 3 bhcs 2rel 4 rol 2dir 1 rola 1inh 1 rolx 1inh 4 rol 2ix1 5 rol 3 sp1 3 rol 1ix 2 pshx 1inh 1 sec 1inh 2 adc 2imm 3 adc 2dir 4 adc 3ext 4 adc 3ix2 5 adc 4 sp2 3 adc 2ix1 4 adc 3 sp1 2 adc 1ix a 5 brset5 3dir 4 bset5 2dir 3 bpl 2rel 4 dec 2dir 1 deca 1inh 1 decx 1inh 4 dec 2ix1 5 dec 3 sp1 3 dec 1ix 2 pulh 1inh 2 cli 1inh 2 ora 2imm 3 ora 2dir 4 ora 3ext 4 ora 3ix2 5 ora 4 sp2 3 ora 2ix1 4 ora 3 sp1 2 ora 1ix b 5 brclr5 3dir 4 bclr5 2dir 3 bmi 2rel 5 dbnz 3dir 3 dbnza 2inh 3 dbnzx 2inh 5 dbnz 3ix1 6 dbnz 4 sp1 4 dbnz 2ix 2 pshh 1inh 2 sei 1inh 2 add 2imm 3 add 2dir 4 add 3ext 4 add 3ix2 5 add 4 sp2 3 add 2ix1 4 add 3 sp1 2 add 1ix c 5 brset6 3dir 4 bset6 2dir 3 bmc 2rel 4 inc 2dir 1 inca 1inh 1 incx 1inh 4 inc 2ix1 5 inc 3 sp1 3 inc 1ix 1 clrh 1inh 1 rsp 1inh 2 jmp 2dir 3 jmp 3ext 4 jmp 3ix2 3 jmp 2ix1 2 jmp 1ix d 5 brclr6 3dir 4 bclr6 2dir 3 bms 2rel 3 tst 2dir 1 tsta 1inh 1 tstx 1inh 3 tst 2ix1 4 tst 3 sp1 2 tst 1ix 1 nop 1inh 4 bsr 2rel 4 jsr 2dir 5 jsr 3ext 6 jsr 3ix2 5 jsr 2ix1 4 jsr 1ix e 5 brset7 3dir 4 bset7 2dir 3 bil 2rel 5 mov 3dd 4 mov 2dix+ 4 mov 3imd 4 mov 2ix+d 1 stop 1inh * 2 ldx 2imm 3 ldx 2dir 4 ldx 3ext 4 ldx 3ix2 5 ldx 4 sp2 3 ldx 2ix1 4 ldx 3 sp1 2 ldx 1ix f 5 brclr7 3dir 4 bclr7 2dir 3 bih 2rel 3 clr 2dir 1 clra 1inh 1 clrx 1inh 3 clr 2ix1 4 clr 3 sp1 2 clr 1ix 1 wait 1inh 1 txa 1inh 2 aix 2imm 3 stx 2dir 4 stx 3ext 4 stx 3ix2 5 stx 4 sp2 3 stx 2ix1 4 stx 3 sp1 2 stx 1ix inh inherent rel relative sp1 stack pointer, 8-bit offset imm immediate ix indexed, no offset sp2 stack pointer, 16-bit offset dir direct ix1 indexed, 8-bit offset ix+ indexed, no offset with ext extended ix2 indexed, 16-bit offset post increment dd direct-direct imd immediate-direct ix1+ indexed, 1-byte offset with ix+d indexed-direct dix+ direct-indexed post increment * pre-byte for stack pointer indexed instructions 0 high byte of opcode in hexadecimal low byte of opcode in hexadecimal 0 5 brset0 3dir cycles opcode mnemonic number of bytes / addressing mode table 6-2. opcode map msb lsb msb lsb MC68HC08AZ32A ? rev 1.0 technical data motorola system integration module (sim) 95 technical data ? MC68HC08AZ32A section 7. system integration module (sim) 7.1 contents 7.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 7.3 sim bus clock control and generation . . . . . . . . . . . . . . . . 98 7.3.1 bustiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 7.3.2 clock start-up from por or lvi reset . . . . . . . . . . . . . . 99 7.3.3 clocks in stop and wait mode . . . . . . . . . . . . . . . . . . . . 99 7.4 reset and system initialization . . . . . . . . . . . . . . . . . . . . . . . 99 7.4.1 external pin reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 7.4.2 active resets from internal sources . . . . . . . . . . . . . . . 101 7.4.2.1 power-on reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 7.4.2.2 computer operating properly (cop) reset . . . . . . . . 103 7.4.2.3 illegal opcode reset . . . . . . . . . . . . . . . . . . . . . . . . . . 103 7.4.2.4 illegal address reset . . . . . . . . . . . . . . . . . . . . . . . . . . 103 7.4.2.5 low-voltage inhibit (lvi) reset . . . . . . . . . . . . . . . . . 104 7.5 sim counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 7.5.1 sim counter during power-on reset . . . . . . . . . . . . . . . 104 7.5.2 sim counter during stop mode recovery . . . . . . . . . . 105 7.5.3 sim counter and reset states . . . . . . . . . . . . . . . . . . . . 105 7.6 exception control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 7.6.1 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 7.6.1.1 hardware interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 7.6.1.2 swi instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 7.6.2 reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 7.7 break interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 7.7.1 status flag protection in break mode . . . . . . . . . . . . . . 108 7.8 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 7.8.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 7.8.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 system integration module (sim) technical data MC68HC08AZ32A ? rev 1.0 96 system integration module (sim) motorola 7.9 sim registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 7.9.1 sim break status register (sbsr) . . . . . . . . . . . . . . . . . 112 7.9.2 sim reset status register (srsr) . . . . . . . . . . . . . . . . . 114 7.9.3 sim break flag control register (sbfcr) . . . . . . . . . . . 115 7.2 introduction this section describes the system integration module, which supports up to 24 external and/or internal interrupts. together with the cpu, the sim controls all mcu activities. a block diagram of the sim is shown in figure 7-1 . table 7-1 is a summary of the sim i/o registers. the sim is a system state controller that coordinates cpu and exception timing. the sim is responsible for: bus clock generation and control for cpu and peripherals ? stop/wait/reset/break entry and recovery ? internal clock control master reset control, including power-on reset (por) and cop timeout interrupt control: ? acknowledge timing ? arbitration control timing ? vector address generation cpu enable/disable timing system integration module (sim) introduction MC68HC08AZ32A ? rev 1.0 technical data motorola system integration module (sim) 97 figure 7-1. sim block diagram table 7-1. sim i/o register summary register name bit 7 6 5 4 3 2 1 bit 0 addr. sim break status register (sbsr) r: rrrrrr bw r$fe00 w: 0 sim reset status register (srsr) r: por pin cop ilop ilad 0 lvi 0 $fe01 w: sim break flag control register (sbfcr) bcfe r r r r r r r $fe03 r = reserved for factory test = unimplemented stop/wait clock control por control reset pin control module stop module wait cpu stop (from cpu) cpu wait (from cpu) simoscen (to cgm) cgmout (from cgm) internal clocks master reset control reset pin logic lvi (from lvi module) illegal opcode (from cpu) illegal address (from address map decoders) cop (from cop module) interrupt sources cpu interface reset control sim counter cop clock cgmxclk (from cgm) 2 interrupt control and priority decode sim reset status register clock generators system integration module (sim) technical data MC68HC08AZ32A ? rev 1.0 98 system integration module (sim) motorola table 7-2 shows the internal signal names used in this section. 7.3 sim bus clock control and generation the bus clock generator provides system clock signals for the cpu and peripherals on the mcu. the system clocks are generated from an incoming clock, cgmout, as shown in figure 7-2 . this clock can come from either an external oscillator or from the on-chip pll. see clock generator module (cgm) on page 117. figure 7-2. cgm clock signals table 7-2. signal naming conventions signal name description cgmxclk buffered version of osc1 from clock generator module (cgm) cgmvclk pll output cgmout pll-based or osc1-based clock output from cgm module (bus clock = cgmout divided by two) iab internal address bus idb internal data bus porrst signal from the power-on reset module to the sim irst internal reset signal r/w read/writesignal pll osc1 cgmxclk 2 sim cgm ptc3 clock select circuit cgmvclk bcs 2 a b s * cgmout * when s = 1, cgmout = b user mode sim counter bus clock generators monitor mode system integration module (sim) reset and system initialization MC68HC08AZ32A ? rev 1.0 technical data motorola system integration module (sim) 99 7.3.1 bustiming in user mode , the internal bus frequency is either the crystal oscillator output (cgmxclk) divided by four or the pll output (cgmvclk) divided by four. see clock generator module (cgm) on page 117. 7.3.2 clock start-up from por or lvi reset when the power-on reset module or the low-voltage inhibit module generates a reset, the clocks to the cpu and peripherals are inactive and held in an inactive phase until after the 4096 cgmxclk cycle por timeout has been completed. the rst pin is driven low by the sim during this entire period. the bus clocks start upon completion of the timeout. 7.3.3 clocks in stop and wait mode upon exit from stop mode (by an interrupt, break, or reset), the sim allows cgmxclk to clock the sim counter. the cpu and peripheral clocks do not become active until after the stop delay timeout. this timeout is selectable as 4096 or 32 cgmxclk cycles. see stop mode on page 111. in wait mode, the cpu clocks are inactive. the sim also produces two sets of clocks for other modules. refer to the wait mode subsection of each module to see if the module is active or inactive in wait mode. some modules can be programmed to be active in wait mode. 7.4 reset and system initialization the mcu has the following reset sources: power-on reset module (por) external reset pin (rst ) computer operating properly module (cop) low-voltage inhibit module (lvi) system integration module (sim) technical data MC68HC08AZ32A ? rev 1.0 100 system integration module (sim) motorola illegal opcode illegal address all of these resets produce the vector $fffe ? ffff ($fefe ? feff in monitor mode) and assert the internal reset signal (irst). irst causes all registers to be returned to their default values and all modules to be returned to their reset states. an internal reset clears the sim counter, see sim counter on page 104, but an external reset does not. each of the resets sets a corresponding bit in the sim reset status register (srsr). see sim registers on page 112. 7.4.1 external pin reset pulling the asynchronous rst pin low halts all processing. the pin bit of the sim reset status register (srsr) is set as long as rst is held low for a minimum of 67 cgmxclk cycles, assuming that neither the por nor the lvi was the source of the reset. see table 7-3 for details. figure 7-3 shows the relative timing. figure 7-3. external reset timing table 7-3. pin bit set timing reset type number of cycles required to set pin por/lvi 4163 (4096 + 64 + 3) all others 67 (64 + 3) rst iab pc vect h vect l cgmout system integration module (sim) reset and system initialization MC68HC08AZ32A ? rev 1.0 technical data motorola system integration module (sim) 101 7.4.2 active resets from internal sources all internal reset sources actively pull the rst pin low for 32 cgmxclk cycles to allow for resetting of external peripherals. the internal reset signal irst continues to be asserted for an additional 32 cycles. see figure 7-4 . an internal reset can be caused by an illegal address, illegal opcode, cop timeout, lvi, or por. see figure 7-5 . note that for lvi or por resets, the sim cycles through 4096 cgmxclk cycles, during which the sim forces the rst pin low. the internal reset signal then follows the sequence from the falling edge of rst as shown in figure 7-4 . figure 7-4. internal reset timing the cop reset is asynchronous to the bus clock. figure 7-5. sources of internal reset the active reset feature allows the part to issue a reset to peripherals and other chips within a system built around the mcu. irst rst rst pulled low by mcu iab 32 cycles 32 cycles vector high cgmxclk illegal address rst illegal opcode rst coprst lvi por internal reset system integration module (sim) technical data MC68HC08AZ32A ? rev 1.0 102 system integration module (sim) motorola 7.4.2.1 power-on reset when power is first applied to the mcu, the power-on reset module (por) generates a pulse to indicate that power-on has occurred. the external reset pin (rst ) is held low while the sim counter counts out 4096 cgmxclk cycles. 64 cgmxclk cycles later, the cpu and memories are released from reset to allow the reset vector sequence to occur. at power-on, the following events occur: a por pulse is generated the internal reset signal is asserted the sim enables cgmout internal clocks to the cpu and modules are held inactive for 4096 cgmxclk cycles to allow the oscillator to stabilize the rst pin is driven low during the oscillator stabilization time the por bit of the sim reset status register (srsr) is set and all other bits in the register are cleared figure 7-6. por recovery porrst osc1 cgmxclk cgmout rst iab 4096 cycles 32 cycles 32 cycles $fffe $ffff system integration module (sim) reset and system initialization MC68HC08AZ32A ? rev 1.0 technical data motorola system integration module (sim) 103 7.4.2.2 computer operating properly (cop) reset an input to the sim is reserved for the cop reset signal. the overflow of the cop counter causes an internal reset and sets the cop bit in the sim reset status register (srsr). the sim actively pulls down the rst pin for all internal reset sources. to prevent a cop module timeout, a value (any value) should be written to location $ffff. writing to location $ffff clears the cop counter and bits 12 through 4 of the sim counter. the sim counter output, which occurs at least every 2 13 ? 2 4 cgmxclk cycles, drives the cop counter. the cop should be serviced as soon as possible out of reset to guarantee the maximum amount of time before the first timeout. the cop module is disabled if the rst pin or the irq pin is held at v dd +v hi while the mcu is in monitor mode. the cop module can be disabled only through combinational logic conditioned with the high voltage signal on the rst or the irq pin. this prevents the cop from becoming disabled as a result of external noise. during a break state, v dd +v hi on the rst pin disables the cop module. 7.4.2.3 illegal opcode reset the sim decodes signals from the cpu to detect illegal instructions. an illegal instruction sets the ilop bit in the sim reset status register (srsr) and causes a reset. if the stop enable bit, stop, in the mask option register is logic ? 0 ? , the sim treats the stop instruction as an illegal opcode and causes an illegal opcode reset. the sim actively pulls down the rst pin for all internal reset sources. 7.4.2.4 illegal address reset an opcode fetch from an unmapped address generates an illegal address reset. the sim verifies that the cpu is fetching an opcode prior to asserting the ilad bit in the sim reset status register srsr) and resetting the mcu. a data fetch from an unmapped address does not generate a reset. the sim actively pulls down the rst pin for all internal reset sources. system integration module (sim) technical data MC68HC08AZ32A ? rev 1.0 104 system integration module (sim) motorola note: extra care should be exercised if code in this part has been taken from another hc08 with a different memory map since some legal addresses could become illegal addresses on a smaller rom. it is the user?s responsibility to check their code for illegal addresses. older hc08s may have a different illegal address reset specification. 7.4.2.5 low-voltage inhibit (lvi) reset the low-voltage inhibit module (lvi) asserts its output to the sim when the v dd voltage falls to the lvi tripf voltage. the lvi bit in the sim reset status register (srsr) is set, and the external reset pin (rst ) is held low while the sim counter counts out 4096 cgmxclk cycles. 64 cgmxclk cycles later, the cpu is released from reset to allow the reset vector sequence to occur. the sim actively pulls down the rst pin for all internal reset sources. 7.5 sim counter the sim counter is used by the power-on reset module (por) and in stop mode recovery to allow the oscillator time to stabilize before enabling the internal bus (ibus) clocks. the sim counter also serves as a prescaler for the computer operating properly (cop) module. the sim counter overflow supplies the clock for the cop module. the sim counter is 13 bits long and is clocked by the falling edge of cgmxclk. 7.5.1 sim counter during power-on reset the power-on reset (por) module detects power applied to the mcu. at power-on, the por circuit asserts the signal porrst. once the sim is initialized, it enables the clock generation module (cgm) to drive the bus clock state machine. system integration module (sim) exception control MC68HC08AZ32A ? rev 1.0 technical data motorola system integration module (sim) 105 7.5.2 sim counter during stop mode recovery the sim counter is also used for stop mode recovery. the stop instruction clears the sim counter. after an interrupt or reset, the sim senses the state of the short stop recovery bit, ssrec, in the mask option register. if the ssrec bit is a logic ? 1 ? , then the stop recovery is reduced from the normal delay of 4096 cgmxclk cycles down to 32 cgmxclk cycles. this is ideal for applications using canned oscillators that do not require long start-up times from stop mode. external crystal applications should use the full stop recovery time, that is, with ssrec cleared. 7.5.3 sim counter and reset states external reset has no effect on the sim counter. (see stop mode on page 111 for details). the sim counter is free-running after all reset states, see active resets from internal sources on page 101 for counter control and internal reset recovery sequences. 7.6 exception control normal, sequential program execution can be changed in three different ways: interrupts ? maskable hardware cpu interrupts ? non-maskable software interrupt instruction (swi) reset break interrupts 7.6.1 interrupts at the beginning of an interrupt, the cpu saves the cpu register contents onto the stack and sets the interrupt mask (i-bit) to prevent additional interrupts. at the end of an interrupt, the rti instruction recovers the cpu register contents from the stack so that normal system integration module (sim) technical data MC68HC08AZ32A ? rev 1.0 106 system integration module (sim) motorola processing can resume. figure 7-7 shows interrupt entry timing, and figure 7-8 shows interrupt recovery timing. . figure 7-7 . interrupt entry interrupts are latched, and arbitration is performed in the sim at the start of interrupt processing. the arbitration result is a constant that the cpu uses to determine which vector to fetch. once an interrupt is latched by the sim, no other interrupt may take precedence, regardless of priority, until the latched interrupt is serviced (or the i-bit is cleared). see figure 7-8 . figure 7-8. interrupt recovery module idb r/w interrupt dummy sp sp ? 1 sp ? 2 sp ? 3 sp ? 4 vect h vect l start address iab dummy pc ? 1[7:0] pc ? 1[15:8] x a ccr v data h v data l opcode i-bit module idb r/w interrupt sp ? 4 sp ? 3 sp ? 2 sp ? 1 sp pc pc + 1 iab ccr a x pc ? 1[7:0] pc ? 1[1 5:8 ] opcode operand i-bit system integration module (sim) exception control MC68HC08AZ32A ? rev 1.0 technical data motorola system integration module (sim) 107 7.6.1.1 hardware interrupts processing of a hardware interrupt begins after completion of the current instruction. when the instruction is complete, the sim checks all pending hardware interrupts. if interrupts are not masked (i-bit clear in the condition code register), and if the corresponding interrupt enable bit is set, the sim proceeds with interrupt processing; otherwise, the next instruction is fetched and executed. if more than one interrupt is pending at the end of an instruction execution, the highest priority interrupt is serviced first. figure 7-8 demonstrates what happens when two interrupts are pending. if an interrupt is pending upon exit from the original interrupt service routine, the pending interrupt is serviced before the lda instruction is executed. the lda opcode is prefetched by both the int1 and int2 rti instructions. however, in the case of the int1 rti prefetch, this is a redundant operation. note: to maintain compatibility with the m6805 family, the h register is not pushed on the stack during interrupt entry. if the interrupt service routine figure 7-9. interrupt recognition example cli lda int1 pulh rti int2 background routine #$ff pshh int1 interrupt service routine pulh rti pshh int2 interrupt service routine system integration module (sim) technical data MC68HC08AZ32A ? rev 1.0 108 system integration module (sim) motorola modifies the h register or uses the indexed addressing mode, software should save the h register and then restore it prior to exiting the routine. 7.6.1.2 swi instruction the swi instruction is a non-maskable instruction that causes an interrupt regardless of the state of the interrupt mask (i-bit) in the condition code register. note: a software interrupt pushes pc onto the stack. a software interrupt does not push pc ? 1, as a hardware interrupt does. 7.6.2 reset all reset sources always have equal and highest priority and cannot be arbitrated. 7.7 break interrupts the break module can stop normal program flow at a software- programmable break point by asserting its break interrupt output. see break module on page 149. the sim puts the cpu into the break state by forcing it to the swi vector location. refer to the break interrupt subsection of each module to see how each module is affected by the break state. 7.7.1 status flag protection in break mode the sim controls whether status flags contained in other modules can be cleared during break mode. the user can select whether flags are protected from being cleared by properly initializing the break clear flag enable bit (bcfe) in the sim break flag control register (sbfcr). protecting flags in break mode ensures that set flags will not be cleared while in break mode. this protection allows registers to be freely read and written during break mode without losing status flag information. system integration module (sim) low-power modes MC68HC08AZ32A ? rev 1.0 technical data motorola system integration module (sim) 109 setting the bcfe bit enables the clearing mechanisms. once cleared in break mode, a flag remains cleared even when break mode is exited. status flags with a two-step clearing mechanism ? for example, a read of one register followed by the read or write of another ? are protected, even when the first step is accomplished prior to entering break mode. upon leaving break mode, execution of the second step will clear the flag as normal. 7.8 low-power modes executing the stop/wait instruction puts the mcu in a low-power- consumption mode for standby situations. the sim holds the cpu in a non-clocked state. the operation of each of these modes is described below. both stop and wait clear the interrupt mask (i) in the condition code register, allowing interrupts to occur. 7.8.1 wait mode in wait mode, the cpu clocks are inactive while the peripheral clocks continue to run. figure 7-10 shows the timing for wait mode entry. a module that is active during wait mode can wake up the cpu with an interrupt if the interrupt is enabled. stacking for the interrupt begins one cycle after the wait instruction during which the interrupt occurred. in wait mode, the cpu clocks are inactive. refer to the wait mode subsection of each module to see if the module is active or inactive in wait mode. some modules can be programmed to be active in wait mode. wait mode can also be exited by a reset or break. a break interrupt during wait mode sets the sim break wait bit, bw, in the sim break status register (sbsr). if the cop disable bit, copd, in the mask option register is ? 0 ? , then the computer operating properly (cop) module is enabled and remains active in wait mode. system integration module (sim) technical data MC68HC08AZ32A ? rev 1.0 110 system integration module (sim) motorola figure 7-10. wait mode entry timing figure 7-10 and figure 7-12 show the timing for wait recovery. figure 7-12. wait recovery from internal reset figure 7-11. wait recovery from interrupt or break wait addr + 1 same same iab idb previous data next opcode same wait addr same r/w note: previous data can be operand data or the wait opcode, depending on the last instruction. $6e0c $6e0b $00ff $00fe $00fd $00fc $a6 $a6 $01 $0b $6e $a6 iab idb exitstopwait note: exitstopwait = rst pin or cpu interrupt or break interrupt iab idb rst $a6 $a6 $6e0b rst vct h rst vct l $a6 cgmxclk 32 cycles 32 cycles system integration module (sim) low-power modes MC68HC08AZ32A ? rev 1.0 technical data motorola system integration module (sim) 111 7.8.2 stop mode in stop mode, the sim counter is reset and the system clocks are disabled. an interrupt request from a module can cause an exit from stop mode. stacking for interrupts begins after the selected stop recovery time has elapsed. reset also causes an exit from stop mode. the sim disables the clock generator module outputs (cgmout and cgmxclk) in stop mode, stopping the cpu and peripherals. stop recovery time is selectable using the ssrec bit in the mask option register (mor). if ssrec is set, stop recovery is reduced from the normal delay of 4096 cgmxclk cycles down to 32. this is ideal for applications using canned oscillators that do not require long start-up times from stop mode. note: external crystal applications should use the full stop recovery time by clearing the ssrec bit. the break module is inactive in stop mode. the stop instruction does not affect break module register states. the sim counter is held in reset from the execution of the stop instruction until the beginning of stop recovery. it is then used to time the recovery period. figure 7-13 shows stop mode entry timing. figure 7-13. stop mode entry timing stop addr + 1 same same iab idb previous data next opcode same stop addr same r/w cpustop note: previous data can be operand data or the stop opcode, depending on the last instruction. system integration module (sim) technical data MC68HC08AZ32A ? rev 1.0 112 system integration module (sim) motorola figure 7-14. stop mode recovery from interrupt 7.9 sim registers the sim has three memory mapped registers. table 7-4 shows the mapping of these registers. 7.9.1 sim break status register (sbsr) the sim break status register contains a flag to indicate that a break caused an exit from stop or wait mode. cgmxclk int/break iab stop + 2 stop + 2 sp sp ? 1 sp ? 2 sp ? 3 stop +1 stop recovery period table 7-4. sim registers address register access mode $fe00 sbsr user $fe01 srsr user $fe03 sbfcr user bit 7654321bit 0 sbsr $fe00 read: rrrrrr bw r write: note (1) reset: 0 r = reserved for factory test 1. writing a logic ? 0 ? clears bw. figure 7-15. sim break status register (sbsr) system integration module (sim) sim registers MC68HC08AZ32A ? rev 1.0 technical data motorola system integration module (sim) 113 bw ? sim break wait this status bit is useful in applications requiring a return to wait mode after exiting from a break interrupt. bw can be cleared by writing a logic ? 0 ? to it. reset clears bw. 1 = wait mode was exited by break interrupt 0 = wait mode was not exited by break interrupt bw can be read within the break state swi routine. the user can modify the return address on the stack by subtracting one from it. the following code is an example of this. ; ; ; this code works if the h register has been pushed onto the stack in the break service routine software. this code should be executed at the end of the break service routine software. hibyte equ 5 lobyte equ 6 ; if not bw, do rti brclr bw,sbsr, return ; ; see if wait mode was exited by break. tst lobyte,sp ; if returnlo is not ?0?, bne dolo ; then just decrement low byte. dec hibyte,sp ; else deal with high byte, too. dolo dec lobyte,sp ; point to wait opcode. return pulh rti ; restore h register. system integration module (sim) technical data MC68HC08AZ32A ? rev 1.0 114 system integration module (sim) motorola 7.9.2 sim reset status register (srsr) this register contains six flags that show the source of the last reset. the sim reset status register can be cleared by reading it. a power-on reset sets the por bit and clears all other bits in the register. por ? power-on reset bit 1 = last reset caused by por circuit 0 = read of srsr pin ? external reset bit 1 = last reset caused by external reset pin (rst ) 0 = por or read of srsr cop ? computer operating properly reset bit 1 = last reset caused by cop counter 0 = por or read of srsr ilop ? illegal opcode reset bit 1 = last reset caused by an illegal opcode 0 = por or read of srsr ilad ? illegal address reset bit (opcode fetches only) 1 = last reset caused by an opcode fetch from an illegal address 0 = por or read of srsr lvi ? low-voltage inhibit reset bit 1 = last reset was caused by the lvi circuit 0 = por or read of srsr bit 7654321bit 0 srsr $fe01 read: por pin cop ilop ilad 0 lvi 0 write: por:10000000 = unimplemented figure 7-16. sim reset status register (srsr) system integration module (sim) sim registers MC68HC08AZ32A ? rev 1.0 technical data motorola system integration module (sim) 115 7.9.3 sim break flag control register (sbfcr) the sim break control register contains a bit that enables software to clear status bits while the mcu is in a break state. bcfe ? break clear flag enable bit this read/write bit enables software to clear status bits by accessing status registers while the mcu is in a break state. to clear status bits during the break state, the bcfe bit must be set. 1 = status bits clearable during break 0 = status bits not clearable during break bit 7654321bit 0 sbfcr $fe03 read: bcferrrrrrr write: reset: 0 r = reserved for factory test figure 7-17. sim break flag control register (sbfcr) system integration module (sim) technical data MC68HC08AZ32A ? rev 1.0 116 system integration module (sim) motorola MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 117 technical data ? MC68HC08AZ32A section 8. clock generator module (cgm) 8.1 contents 8.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 8.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 8.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 8.4.1 crystal oscillator circuit . . . . . . . . . . . . . . . . . . . . . . . . . 119 8.4.2 phase-locked loop circuit (pll) . . . . . . . . . . . . . . . . . . 121 8.4.2.1 circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 8.4.2.2 acquisition and tracking modes . . . . . . . . . . . . . . . . 123 8.4.2.3 manual and automatic pll bandwidth modes . . . . . 123 8.4.2.4 programming the pll . . . . . . . . . . . . . . . . . . . . . . . . . 125 8.4.2.5 special programming exceptions . . . . . . . . . . . . . . . 127 8.4.3 base clock selector circuit . . . . . . . . . . . . . . . . . . . . . . 127 8.4.4 cgm external connections . . . . . . . . . . . . . . . . . . . . . . . 128 8.5 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 8.5.1 crystal amplifier input pin (osc1) . . . . . . . . . . . . . . . . . 129 8.5.2 crystal amplifier output pin (osc2) . . . . . . . . . . . . . . . 129 8.5.3 external filter capacitor pin (cgmxfc) . . . . . . . . . . . . 129 8.5.4 analog power pin (v dda ) . . . . . . . . . . . . . . . . . . . . . . . . . 130 8.5.5 oscillator enable signal (simoscen) . . . . . . . . . . . . . . 130 8.5.6 crystal output frequency signal (cgmxclk) . . . . . . . 130 8.5.7 cgm base clock output (cgmout) . . . . . . . . . . . . . . . 130 8.5.8 cgm cpu interrupt (cgmint) . . . . . . . . . . . . . . . . . . . . . 130 8.6 cgm registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 8.6.1 pll control register . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 8.6.2 pll bandwidth control register . . . . . . . . . . . . . . . . . . 133 8.6.3 pll programming register . . . . . . . . . . . . . . . . . . . . . . . 135 8.7 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 8.8 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 118 clock generator module (cgm) motorola 8.8.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 8.8.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 8.9 cgm during break interrupts . . . . . . . . . . . . . . . . . . . . . . . 138 8.10 acquisition/lock time specifications . . . . . . . . . . . . . . . . 138 8.10.1 acquisition/lock time definitions . . . . . . . . . . . . . . . . . 138 8.10.2 parametric influences on reaction time . . . . . . . . . . . . 140 8.10.3 choosing a filter capacitor . . . . . . . . . . . . . . . . . . . . . . 141 8.10.4 reaction time calculation . . . . . . . . . . . . . . . . . . . . . . . 141 8.2 introduction the cgm generates the crystal clock signal, cgmxclk, which operates at the frequency of the crystal. the cgm also generates the base clock signal, cgmout, from which the system clocks are derived. cgmout is based on either the crystal clock divided by two or the phase-locked loop (pll) clock, cgmvclk, divided by two. the pll is a frequency generator designed for use with 1-mhz to 16-mhz crystals or ceramic resonators. the pll can generate an 8-mhz bus frequency without using high frequency crystals. 8.3 features features of the cgm include: phase-locked loop with output frequency in integer multiples of the crystal reference programmable hardware voltage-controlled oscillator (vco) for low-jitter operation automatic bandwidth control mode for low-jitter operation automatic frequency lock detector cpu interrupt on entry or exit from locked condition clock generator module (cgm) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 119 8.4 functional description the cgm consists of three major submodules: crystal oscillator circuit ? the crystal oscillator circuit generates the constant crystal frequency clock, cgmxclk. phase-locked loop (pll) ? the pll generates the programmable vco frequency clock cgmvclk. base clock selector circuit ? this software-controlled circuit selects either cgmxclk divided by two or the vco clock, cgmvclk, divided by two as the base clock, cgmout. the system clocks are derived from cgmout. figure 8-1 shows the structure of the cgm. 8.4.1 crystal oscillator circuit the crystal oscillator circuit consists of an inverting amplifier and an external crystal. the osc1 pin is the input to the amplifier and the osc2 pin is the output. the simoscen signal enables the crystal oscillator circuit. the cgmxclk signal is the output of the crystal oscillator circuit and runs at a rate equal to the crystal frequency. cgmxclk is then buffered to produce cgmrclk, the pll reference clock. cgmxclk can be used by other modules which require precise timing for operation. the duty cycle of cgmxclk is not guaranteed to be 50% and depends on external factors, including the crystal and related external components. an externally generated clock also can feed the osc1 pin of the crystal oscillator circuit. connect the external clock to the osc1 pin and let the osc2 pin float. clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 120 clock generator module (cgm) motorola figure 8-1. cgm block diagram phase detector loop filter frequency divider voltage controlled oscillator bandwidth control lock detector clock cgmvdv cgmvclk interrupt control cgmint cgmrdv pll analog cgmrclk select circuit lock auto acq vrs7 ? vrs4 pllie pllf mul7 ? mul4 v dda cgmxfc v ss osc1 cgmxclk ptc3 monitor mode bcs 2 a b s* cgmout *when s = 1, cgmout = b user mode clock generator module (cgm) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 121 8.4.2 phase-locked loop circuit (pll) the pll is a frequency generator that can operate in either acquisition mode or tracking mode, depending on the accuracy of the output frequency. the pll can change between acquisition and tracking modes either automatically or manually. 8.4.2.1 circuits the pll consists of these circuits: voltage-controlled oscillator (vco) modulo vco frequency divider phase detector loop filter lock detector register name bit 7654321bit 0 pll control register (pctl) read: pllie pllf pllon bcs 1111 write: reset:00101111 pll bandwidth control register (pbwc) read: auto lock acq xld 0000 write: reset:00000000 pll programming register (ppg) read: mul7 mul6 mul5 mul4 vrs7 vrs6 vrs5 vrs4 write: reset:01100110 = unimplemented figure 8-2. i/o register summary table 8-1. i/o register address summary register pctl pbwc ppg address $001c $001d $001e clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 122 clock generator module (cgm) motorola the operating range of the vco is programmable for a wide range of frequencies and for maximum immunity to external noise, including supply and cgmxfc noise. the vco frequency is bound to a range from roughly one-half to twice the center-of-range frequency, f cgmvrs . modulating the voltage on the cgmxfc pin changes the frequency within this range. by design, f cgmvrs is equal to the nominal center-of- range frequency, f nom , (4.9152 mhz) times a linear factor l or (l)f nom . cgmrclk is the pll reference clock, a buffered version of cgmxclk. cgmrclk runs at a frequency, f cgmrclk , and is fed to the pll through a buffer. the buffer output is the final reference clock, cgmrdv, running at a frequency f cgmrdv =f cgmrclk . the vco ? s output clock, cgmvclk, running at a frequency f cgmvclk , is fed back through a programmable modulo divider. the modulo divider reduces the vco clock by a factor, n. the divider ? s output is the vco feedback clock, cgmvdv, running at a frequency f cgmvdv =f cgmvclk /n. see programming the pll on page 125 for more information. the phase detector then compares the vco feedback clock, cgmvdv, with the final reference clock, cgmrdv. a correction pulse is generated based on the phase difference between the two signals. the loop filter then slightly alters the dc voltage on the external capacitor connected to cgmxfc based on the width and direction of the correction pulse. the filter can make fast or slow corrections depending on its mode, as described in acquisition and tracking modes on page 123. the value of the external capacitor and the reference frequency determines the speed of the corrections and the stability of the pll. the lock detector compares the frequencies of the vco feedback clock, cgmvdv, and the final reference clock, cgmrdv. therefore, the speed of the lock detector is directly proportional to the final reference frequency, f cgmrdv . the circuit determines the mode of the pll and the lock condition based on this comparison. clock generator module (cgm) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 123 8.4.2.2 acquisition and tracking modes the pll filter is manually or automatically configurable into one of two operating modes: acquisition mode ? in acquisition mode, the filter can make large frequency corrections to the vco. this mode is used at pll startup or when the pll has suffered a severe noise hit and the vco frequency is far off the desired frequency. when in acquisition mode, the acq bit is clear in the pll bandwidth control register. see pll bandwidth control register on page 133. tracking mode ? in tracking mode, the filter makes only small corrections to the frequency of the vco. pll jitter is much lower in tracking mode, but the response to noise is also slower. the pll enters tracking mode when the vco frequency is nearly correct, such as when the pll is selected as the base clock source. see base clock selector circuit on page 127. the pll is automatically in tracking mode when it ? s not in acquisition mode or when the acq bit is set. 8.4.2.3 manual and automatic pll bandwidth modes the pll can change the bandwidth or operational mode of the loop filter manually or automatically. in automatic bandwidth control mode (auto = 1), the lock detector automatically switches between acquisition and tracking modes. automatic bandwidth control mode also is used to determine when the vco clock, cgmvclk, is safe to use as the source for the base clock, cgmout. see pll bandwidth control register on page 133. if pll cpu interrupt requests are enabled, the software can wait for a pll cpu interrupt request and then check the lock bit. if cpu interrupts are disabled, software can poll the lock bit continuously (during pll startup, usually) or at periodic intervals. in either case, when the lock bit is set, the vco clock is safe to use as the source for the base clock. see base clock selector circuit on page 127. if the vco is selected as the source for the base clock and the lock bit is clear, the pll has suffered a severe noise hit and the software must take appropriate action, depending on the application. see interrupts on page 137. clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 124 clock generator module (cgm) motorola these conditions apply when the pll is in automatic bandwidth control mode: the acq bit (see 8.6.2 pll bandwidth control register.) is a read-only indicator of the mode of the filter. see acquisition and tracking modes on page 123. the acq bit is set when the vco frequency is within a certain tolerance, ? trk , and is cleared when the vco frequency is out of a certain tolerance, ? unt . see electrical specifications on page 423. the lock bit is a read-only indicator of the locked state of the pll. the lock bit is set when the vco frequency is within a certain tolerance, ? lock , and is cleared when the vco frequency is out of a certain tolerance, ? unl . see electrical specifications on page 423. cpu interrupts can occur if enabled (pllie = 1) when the pll ? s lock condition changes, toggling the lock bit. see pll control register on page 131. the pll also can operate in manual mode (auto = 0). manual mode is used by systems that do not require an indicator of the lock condition for proper operation. such systems typically operate well below f busmax and require fast startup. the following conditions apply when in manual mode: acq is a writable control bit that controls the mode of the filter. before turning on the pll in manual mode, the acq bit must be clear. before entering tracking mode (acq = 1), software must wait a given time, t acq (see electrical specifications on page 423), after turning on the pll by setting pllon in the pll control register (pctl). software must wait a given time, t al , after entering tracking mode before selecting the pll as the clock source to cgmout (bcs = 1). the lock bit is disabled. cpu interrupts from the cgm are disabled. clock generator module (cgm) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 125 8.4.2.4 programming the pll use this 9-step procedure to program the pll. the table below lists the variables used and their meaning (please also reference figure 8-1 ). 1. choose the desired bus frequency, f busdes . example: f busdes = 8 mhz 2. calculate the desired vco frequency, f vclkdes . f vclkdes = 4 f busdes example: f vclkdes = 4 8 mhz = 32 mhz 3. using a reference frequency, f rclk , equal to the crystal frequency, calculate the vco frequency multiplier, n. round the result to the nearest integer. example: 4. calculate the vco frequency, f cgmvclk . example: f cgmvclk = 8 4 mhz = 32 mhz table 8-2. variable definitions variable definition f busdes desired bus clock frequency f vclkdes desired vco clock frequency f cgmrclk chosen reference crystal frequency f cgmvclk calculated vco clock frequency f bus calculated bus clock frequency f nom nominal vco center frequency f cgmvrs shifted vco center frequency n f vclkdes f cgmrclk ------------------------- = n 32 mhz 4 mhz -------------------- =8 = f cgmvclk nf cgmrclk = clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 126 clock generator module (cgm) motorola 5. calculate the bus frequency, f bus , and compare f bus with f busdes . example: 6. if the calculated f bus is not within the tolerance limits of your application, select another f busdes or another f rclk . 7. using the value 4.9152 mhz for f nom , calculate the vco linear range multiplier, l. the linear range multiplier controls the frequency range of the pll. example: 8. calculate the vco center-of-range frequency, f cgmvrs . the center-of-range frequency is the midpoint between the minimum and maximum frequencies attainable by the pll. f cgmvrs = l f nom example: f cgmvrs = 7 4.9152 mhz = 34.4 mhz note: for proper operation, . exceeding the recommended maximum bus frequency or vco frequency can crash the mcu. 9. program the pll registers accordingly: a. in the upper four bits of the pll programming register (ppg), program the binary equivalent of n. b. in the lower four bits of the pll programming register (ppg), program the binary equivalent of l. f bus f cgmvclk 4 ----------------------- - = f bus 32 mhz 4 -------------------- =8 mhz = l round f cgmvclk f nom ----------------------- - ?? ?? = l 32 mhz 4.9152 mhz ------------------------------- - = 7 = f cgmvrs f cgmvclk ? f nom 2 ---------------- clock generator module (cgm) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 127 8.4.2.5 special programming exceptions the programming method described in programming the pll on page 125, does not account for two possible exceptions. a value of 0 for n or l is meaningless when used in the equations given. to account for these exceptions: a 0 value for n is interpreted the same as a value of 1. a 0 value for l disables the pll and prevents its selection as the source for the base clock. see base clock selector circuit on page 127. 8.4.3 base clock selector circuit this circuit is used to select either the crystal clock, cgmxclk, or the vco clock, cgmvclk, as the source of the base clock, cgmout. the two input clocks go through a transition control circuit that waits up to three cgmxclk cycles and three cgmvclk cycles to change from one clock source to the other. during this time, cgmout is held in stasis. the output of the transition control circuit is then divided by two to correct the duty cycle. therefore, the bus clock frequency, which is one-half of the base clock frequency, is one-fourth the frequency of the selected clock (cgmxclk or cgmvclk). the bcs bit in the pll control register (pctl) selects which clock drives cgmout. the vco clock cannot be selected as the base clock source if the pll is not turned on. the pll cannot be turned off if the vco clock is selected. the pll cannot be turned on or off simultaneously with the selection or deselection of the vco clock. the vco clock also cannot be selected as the base clock source if the factor l is programmed to a 0. this value would set up a condition inconsistent with the operation of the pll, so that the pll would be disabled and the crystal clock would be forced as the source of the base clock. clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 128 clock generator module (cgm) motorola 8.4.4 cgm external connections in its typical configuration, the cgm requires seven external components. five of these are for the crystal oscillator and two are for the pll. the crystal oscillator is normally connected in a pierce oscillator configuration, as shown in figure 8-3 . figure 8-3 shows only the logical representation of the internal components and may not represent actual circuitry. the oscillator configuration uses five components: crystal, x 1 fixed capacitor, c 1 tuning capacitor, c 2 (can also be a fixed capacitor) feedback resistor, r b series resistor, r s (optional) the series resistor (r s ) may not be required for all ranges of operation, especially with high-frequency crystals. refer to the crystal manufacturer ? s data for more information. figure 8-3 also shows the external components for the pll: bypass capacitor, c byp filter capacitor, c f routing should be done with great care to minimize signal cross talk and noise. (see acquisition/lock time specifications on page 138 for routing information and more information on the filter capacitor ? s value and its effects on pll performance). clock generator module (cgm) i/o signals MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 129 figure 8-3. cgm external connections 8.5 i/o signals the following paragraphs describe the cgm input/output (i/o) signals. 8.5.1 crystal amplifier input pin (osc1) the osc1 pin is an input to the crystal oscillator amplifier. 8.5.2 crystal amplifier output pin (osc2) the osc2 pin is the output of the crystal oscillator inverting amplifier. 8.5.3 external filter capacitor pin (cgmxfc) the cgmxfc pin is required by the loop filter to filter out phase corrections. a small external capacitor is connected to this pin. note: to prevent noise problems, c f should be placed as close to the cgmxfc pin as possible with minimum routing distances and no routing of other signals across the c f connection. c 1 c 2 c f simoscen cgmxclk r b x 1 r s * c byp *r s can be 0 (shorted) when used with higher-frequency crystals. refer to manufacturer ? s data. osc1 osc2 v ss cgmxfc v dd v dda clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 130 clock generator module (cgm) motorola 8.5.4 analog power pin (v dda ) v dda is a power pin used by the analog portions of the pll. connect the v dda pin to the same voltage potential as the v dd pin. note: route v dda carefully for maximum noise immunity and place bypass capacitors as close as possible to the package. 8.5.5 oscillator enable signal (simoscen) the simoscen signal enables the oscillator and pll. 8.5.6 crystal output frequency signal (cgmxclk) cgmxclk is the crystal oscillator output signal. it runs at the full speed of the crystal (f cgmxclk ) and comes directly from the crystal oscillator circuit. figure 8-3 shows only the logical relation of cgmxclk to osc1 and osc2 and may not represent the actual circuitry. the duty cycle of cgmxclk is unknown and may depend on the crystal and other external factors. also, the frequency and amplitude of cgmxclk can be unstable at startup. 8.5.7 cgm base clock output (cgmout) cgmout is the clock output of the cgm. this signal is used to generate the mcu clocks. cgmout is a 50% duty cycle clock running at twice the bus frequency. cgmout is software programmable to be either the oscillator output, cgmxclk, divided by two or the vco clock, cgmvclk, divided by two. 8.5.8 cgm cpu interrupt (cgmint) cgmint is the cpu interrupt signal generated by the pll lock detector. clock generator module (cgm) cgm registers MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 131 8.6 cgm registers three registers control and monitor operation of the cgm: pll control register (pctl) pll bandwidth control register (pbwc) pll programming register (ppg) 8.6.1 pll control register the pll control register contains the interrupt enable and flag bits, the on/off switch, and the base clock selector bit. pllie ? pll interrupt enable bit this read/write bit enables the pll to generate a cpu interrupt request when the lock bit toggles, setting the pll flag, pllf. when the auto bit in the pll bandwidth control register (pbwc) is clear, pllie cannot be written and reads as logic 0. reset clears the pllie bit. 1 = pll cpu interrupt requests enabled 0 = pll cpu interrupt requests disabled address: $001c bit 7654321bit 0 read: pllie pllf pllon bcs 1111 write: reset:00101111 = unimplemented figure 8-4. pll control register (pctl) clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 132 clock generator module (cgm) motorola pllf ? pll flag bit this read-only bit is set whenever the lock bit toggles. pllf generates a cpu interrupt request if the pllie bit also is set. pllf always reads as logic 0 when the auto bit in the pll bandwidth control register (pbwc) is clear. clear the pllf bit by reading the pll control register. reset clears the pllf bit. 1 = change in lock condition 0 = no change in lock condition note: do not inadvertently clear the pllf bit. be aware that any read or read- modify-write operation on the pll control register clears the pllf bit. pllon ? pll on bit this read/write bit activates the pll and enables the vco clock, cgmvclk. pllon cannot be cleared if the vco clock is driving the base clock, cgmout (bcs = 1). see base clock selector circuit on page 127. reset sets this bit so that the loop can stabilize as the mcu is powering up. 1 = pll on 0 = pll off bcs ? base clock select bit this read/write bit selects either the crystal oscillator output, cgmxclk, or the vco clock, cgmvclk, as the source of the cgm output, cgmout. cgmout frequency is one-half the frequency of the selected clock. bcs cannot be set while the pllon bit is clear. after toggling bcs, it may take up to three cgmxclk and three cgmvclk cycles to complete the transition from one source clock to the other. during the transition, cgmout is held in stasis. see base clock selector circuit on page 127. reset and the stop instruction clear the bcs bit. 1 = cgmvclk divided by two drives cgmout 0 = cgmxclk divided by two drives cgmout note: pllon and bcs have built-in protection that prevents the base clock selector circuit from selecting the vco clock as the source of the base clock if the pll is off. therefore, pllon cannot be cleared when bcs is set, and bcs cannot be set when pllon is clear. if the pll is off clock generator module (cgm) cgm registers MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 133 (pllon = 0), selecting cgmvclk requires two writes to the pll control register. see 8.4.3 on page 127. pctl3 ? pctl0 ? unimplemented these bits provide no function and always read as logic 1s. 8.6.2 pll bandwidth control register the pll bandwidth control register: selects automatic or manual (software-controlled) bandwidth control mode indicates when the pll is locked in automatic bandwidth control mode, indicates when the pll is in acquisition or tracking mode in manual operation, forces the pll into acquisition or tracking mode address: $001d bit 7654321bit 0 read: auto lock acq xld 0000 write: reset:00000000 = unimplemented figure 8-5. pll bandwidth control register (pbwc) clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 134 clock generator module (cgm) motorola auto ? automatic bandwidth control bit this read/write bit selects automatic or manual bandwidth control. when initializing the pll for manual operation (auto = 0), clear the acq bit before turning on the pll. reset clears the auto bit. 1 = automatic bandwidth control 0 = manual bandwidth control lock ? lock indicator bit when the auto bit is set, lock is a read-only bit that becomes set when the vco clock, cgmvclk, is locked (running at the programmed frequency). when the auto bit is clear, lock reads as logic 0 and has no meaning. reset clears the lock bit. 1 = vco frequency correct or locked 0 = vco frequency incorrect or unlocked acq ? acquisition mode bit when the auto bit is set, acq is a read-only bit that indicates whether the pll is in acquisition mode or tracking mode. when the auto bit is clear, acq is a read/write bit that controls whether the pll is in acquisition or tracking mode. in automatic bandwidth control mode (auto = 1), the last-written value from manual operation is stored in a temporary location and is recovered when manual operation resumes. reset clears this bit, enabling acquisition mode. 1 = tracking mode 0 = acquisition mode xld ? crystal loss detect bit when the vco output, cgmvclk, is driving cgmout, this read/write bit can indicate whether the crystal reference frequency is active or not. 1 = crystal reference not active 0 = crystal reference active clock generator module (cgm) cgm registers MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 135 to check the status of the crystal reference, do the following: 1. write a logic 1 to xld. 2. wait n 4 cycles. n is the vco frequency multiplier. 3. read xld. the crystal loss detect function works only when the bcs bit is set, selecting cgmvclk to drive cgmout. when bcs is clear, xld always reads as logic 0. bits 3 ? 0 ? reserved for test these bits enable test functions not available in user mode. to ensure software portability from development systems to user applications, software should write 0s to bits 3 ? 0 when writing to pbwc. 8.6.3 pll programming register the pll programming register contains the programming information for the modulo feedback divider and the programming information for the hardware configuration of the vco. mul7 ? mul4 ? multiplier select bits these read/write bits control the modulo feedback divider that selects the vco frequency multiplier, n. (see circuits on page 121 and programming the pll on page 125). a value of $0 in the multiplier select bits configures the modulo feedback divider the same as a value of $1. reset initializes these bits to $6 to give a default multiply value of 6. address: $001e bit 7654321bit 0 read: mul7 mul6 mul5 mul4 vrs7 vrs6 vrs5 vrs4 write: reset:01100110 figure 8-6. pll programming register (ppg) clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 136 clock generator module (cgm) motorola note: the multiplier select bits have built-in protection that prevents them from being written when the pll is on (pllon = 1). vrs7 ? vrs4 ? vco range select bits these read/write bits control the hardware center-of-range linear multiplier l, which controls the hardware center-of-range frequency, f vrs . (see circuits on page 121, programming the pll on page 125, and pll control register on page 131.) vrs7 ? vrs4 cannot be written when the pllon bit in the pll control register (pctl) is set. see special programming exceptions on page 127. a value of $0 in the vco range select bits disables the pll and clears the bcs bit in the pctl. (see base clock selector circuit on page 127 and special programming exceptions on page 127 for more information.) reset initializes the bits to $6 to give a default range multiply value of 6. note: the vco range select bits have built-in protection that prevents them from being written when the pll is on (pllon = 1) and prevents selection of the vco clock as the source of the base clock (bcs = 1) if the vco range select bits are all clear. the vco range select bits must be programmed correctly. incorrect programming can result in failure of the pll to achieve lock. table 8-3. vco frequency multiplier (n) selection mul7:mul6:mul5:mul4 vco frequency multiplier (n) 0000 1 0001 1 0010 2 0011 3 1101 13 1110 14 1111 15 clock generator module (cgm) interrupts MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 137 8.7 interrupts when the auto bit is set in the pll bandwidth control register (pbwc), the pll can generate a cpu interrupt request every time the lock bit changes state. the pllie bit in the pll control register (pctl) enables cpu interrupt requests from the pll. pllf, the interrupt flag in the pctl, becomes set whether cpu interrupt requests are enabled or not. when the auto bit is clear, cpu interrupt requests from the pll are disabled and pllf reads as logic 0. software should read the lock bit after a pll cpu interrupt request to see if the request was due to an entry into lock or an exit from lock. when the pll enters lock, the vco clock, cgmvclk, divided by two can be selected as the cgmout source by setting bcs in the pctl. when the pll exits lock, the vco clock frequency is corrupt, and appropriate precautions should be taken. if the application is not frequency sensitive, cpu interrupt requests should be disabled to prevent pll interrupt service routines from impeding software performance or from exceeding stack limitations. note: software can select the cgmvclk divided by two as the cgmout source even if the pll is not locked (lock = 0). therefore, software should make sure the pll is locked before setting the bcs bit. 8.8 low-power modes the wait and stop instructions put the mcu in low power- consumption standby modes. 8.8.1 wait mode the cgm remains active in wait mode. before entering wait mode, software can disengage and turn off the pll by clearing the bcs and pllon bits in the pll control register (pctl). less power-sensitive applications can disengage the pll without turning it off. applications that require the pll to wake the mcu from wait mode also can deselect the pll output without turning off the pll. clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 138 clock generator module (cgm) motorola 8.8.2 stop mode the stop instruction disables the cgm and holds low all cgm outputs (cgmxclk, cgmout, and cgmint). if cgmout is being driven by cgmvclk and a stop instruction is executed; the pll will clear the bcs bit in the pll control register, causing cgmout to be driven by cgmxclk. when the mcu recovers from stop, the crystal clock divided by two drives cgmout and bcs remains clear. 8.9 cgm during break interrupts the bcfe bit in the break flag control register (bfcr) enables software to clear status bits during the break state. see break module on page 149). to allow software to clear status bits during a break interrupt, write a logic 1 to the bcfe bit. if a status bit is cleared during the break state, it remains cleared when the mcu exits the break state. to protect the pllf bit during the break state, write a logic 0 to the bcfe bit. with bcfe at logic 0 (its default state), software can read and write the pll control register during the break state without affecting the pllf bit. 8.10 acquisition/lock time specifications the acquisition and lock times of the pll are, in many applications, the most critical pll design parameters. proper design and use of the pll ensures the highest stability and lowest acquisition/lock times. 8.10.1 acquisition/lock time definitions typical control systems refer to the acquisition time or lock time as the reaction time, within specified tolerances, of the system to a step input. in a pll, the step input occurs when the pll is turned on or when it suffers a noise hit. the tolerance is usually specified as a percent of the clock generator module (cgm) acquisition/lock time specifications MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 139 step input or when the output settles to the desired value plus or minus a percent of the frequency change. therefore, the reaction time is constant in this definition, regardless of the size of the step input. for example, consider a system with a 5% acquisition time tolerance. if a command instructs the system to change from 0 hz to 1 mhz, the acquisition time is the time taken for the frequency to reach 1mhz 50 khz. fifty khz = 5% of the 1-mhz step input. if the system is operating at 1 mhz and suffers a ? 100 khz noise hit, the acquisition time is the time taken to return from 900 khz to 1 mhz 5 khz. five khz = 5% of the 100-khz step input. other systems refer to acquisition and lock times as the time the system takes to reduce the error between the actual output and the desired output to within specified tolerances. therefore, the acquisition or lock time varies according to the original error in the output. minor errors may not even be registered. typical pll applications prefer to use this definition because the system requires the output frequency to be within a certain tolerance of the desired frequency regardless of the size of the initial error. the discrepancy in these definitions makes it difficult to specify an acquisition or lock time for a typical pll. therefore, the definitions for acquisition and lock times for this module are: acquisition time, t acq , is the time the pll takes to reduce the error between the actual output frequency and the desired output frequency to less than the tracking mode entry tolerance, ? trk . acquisition time is based on an initial frequency error, (f des ? f orig )/f des , of not more than 100%. in automatic bandwidth control mode (see manual and automatic pll bandwidth modes on page 123), acquisition time expires when the acq bit becomes set in the pll bandwidth control register (pbwc). lock time, t lock , is the time the pll takes to reduce the error between the actual output frequency and the desired output frequency to less than the lock mode entry tolerance, ? lock . lock time is based on an initial frequency error, (f des ? f orig )/f des , of not more than 100%. in automatic bandwidth control mode, lock time clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 140 clock generator module (cgm) motorola expires when the lock bit becomes set in the pll bandwidth control register (pbwc). (see manual and automatic pll bandwidth modes on page 123). obviously, the acquisition and lock times can vary according to how large the frequency error is and may be shorter or longer in many cases. 8.10.2 parametric influences on reaction time acquisition and lock times are designed to be as short as possible while still providing the highest possible stability. these reaction times are not constant, however. many factors directly and indirectly affect the acquisition time. the most critical parameter which affects the reaction times of the pll is the reference frequency, f cgmrdv (please reference figure 8-1 on page 120). this frequency is the input to the phase detector and controls how often the pll makes corrections. for stability, the corrections must be small compared to the desired frequency, so several corrections are required to reduce the frequency error. therefore, the slower the reference the longer it takes to make these corrections. this parameter is also under user control via the choice of crystal frequency f cgmxclk . another critical parameter is the external filter capacitor. the pll modifies the voltage on the vco by adding or subtracting charge from this capacitor. therefore, the rate at which the voltage changes for a given frequency error (thus a change in charge) is proportional to the capacitor size. the size of the capacitor also is related to the stability of the pll. if the capacitor is too small, the pll cannot make small enough adjustments to the voltage and the system cannot lock. if the capacitor is too large, the pll may not be able to adjust the voltage in a reasonable time. see choosing a filter capacitor on page 141. also important is the operating voltage potential applied to v dda . the power supply potential alters the characteristics of the pll. a fixed value is best. variable supplies, such as batteries, are acceptable if they vary within a known range at very slow speeds. noise on the power supply is not acceptable, because it causes small frequency errors which continually change the acquisition time of the pll. clock generator module (cgm) acquisition/lock time specifications MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 141 temperature and processing also can affect acquisition time because the electrical characteristics of the pll change. the part operates as specified as long as these influences stay within the specified limits. external factors, however, can cause drastic changes in the operation of the pll. these factors include noise injected into the pll through the filter capacitor, filter capacitor leakage, stray impedances on the circuit board, and even humidity or circuit board contamination. 8.10.3 choosing a filter capacitor as described in parametric influences on reaction time on page 140, the external filter capacitor, c f , is critical to the stability and reaction time of the pll. the pll is also dependent on reference frequency and supply voltage. the value of the capacitor must, therefore, be chosen with supply potential and reference frequency in mind. for proper operation, the external filter capacitor must be chosen according to this equation: for acceptable values of c fact , (see electrical specifications on page 423). for the value of v dda , choose the voltage potential at which the mcu is operating. if the power supply is variable, choose a value near the middle of the range of possible supply values. this equation does not always yield a commonly available capacitor size, so round to the nearest available size. if the value is between two different sizes, choose the higher value for better stability. choosing the lower size may seem attractive for acquisition time improvement, but the pll may become unstable. also, always choose a capacitor with a tight tolerance ( 20% or better) and low dissipation. 8.10.4 reaction time calculation the actual acquisition and lock times can be calculated using the equations below. these equations yield nominal values under the following conditions: c f c fact v dda f cgmrdv ------------------ - ?? ?? = clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 142 clock generator module (cgm) motorola correct selection of filter capacitor, c f (see choosing a filter capacitor on page 141). room temperature operation negligible external leakage on cgmxfc negligible noise the k factor in the equations is derived from internal pll parameters. k acq is the k factor when the pll is configured in acquisition mode, and k trk is the k factor when the pll is configured in tracking mode. (see acquisition and tracking modes on page 123). note the inverse proportionality between the lock time and the reference frequency. in automatic bandwidth control mode, the acquisition and lock times are quantized into units based on the reference frequency. (see manual and automatic pll bandwidth modes on page 123). a certain number of clock cycles, n acq , is required to ascertain that the pll is within the tracking mode entry tolerance, ? trk , before exiting acquisition mode. a certain number of clock cycles, n trk , is required to ascertain that the pll is within the lock mode entry tolerance, ? lock . therefore, the acquisition time, t acq , is an integer multiple of n acq /f cgmrdv , and the acquisition to lock time, t al , is an integer multiple of n trk /f cgmrdv . also, since the average frequency over the entire measurement period must be within the specified tolerance, the total time usually is longer than t lock as calculated above. t acq v dda f cgmrdv ------------------- - ?? ?? 8 k acq ------------ - ?? ?? = t al v dda f cgmrdv ------------------- - ?? ?? 4 k trk ----------- - ?? ?? = t lock t acq t al + = clock generator module (cgm) acquisition/lock time specifications MC68HC08AZ32A ? rev 1.0 technical data motorola clock generator module (cgm) 143 in manual mode, it is usually necessary to wait considerably longer than t lock before selecting the pll clock (see base clock selector circuit on page 127), because the factors described in parametric influences on reaction time on page 140, may slow the lock time considerably. when defining a limit in software for the maximum lock time, the value must allow for variation due to all of the factors mentioned in this section, especially due to the c f capacitor and application specific influences. the calculated lock time is only an indication and it is the customer ? s responsibility to allow enough of a guard band for their application. prior to finalizing any software and while determining the maximum lock time, take into account all device to device differences. typically, applications set the maximum lock time as an order of magnitude higher than the measured value. this is considered sufficient for all such device to device variation. motorola recommends measuring the lock time of the application system by utilizing dedicated software, running in flash, eeprom or ram. this should toggle a port pin when the pll is first configured and switched on, then again when it goes from acquisition to lock mode and finally again when the pll lock bit is set. the resultant waveform can be captured on an oscilloscope and used to determine the typical lock time for the microcontroller and the associated external application circuit. e.g. note: the filter capacitor should be fully discharged prior to making any measurements. t lock t acq t al t trk complete and lock set init. low signal on port pin t acq complete pll configured and switched on clock generator module (cgm) technical data MC68HC08AZ32A ? rev 1.0 144 clock generator module (cgm) motorola MC68HC08AZ32A ? rev 1.0 technical data motorola mask options 145 technical data ? MC68HC08AZ32A section 9. mask options 9.1 contents 9.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 9.3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 9.2 introduction this section describes the mask options and the mask option registers. the mask options are hardwired connections specified at the same time as the rom code, which allow the user to customize the mcu. the options control the enable or disable of the following functions: resets caused by the lvi module power to the lvi module stop mode recovery time (32 cgmxclk cycles or 4096 cgmxclk cycles) rom security (1) stop instruction computer operating properly (cop) module enable eeprom read protection (1) cop time-out period eeprom reference clock source 1. no security feature is absolutely secure. however, motorola ? s strategy is to make reading or copying the rom/eeprom data difficult for unauthorized users mask options technical data MC68HC08AZ32A ? rev 1.0 146 mask options motorola 9.3 functional description lvistop ? lvi stop mode enable bit lvistop enables the lvi module in stop mode. see low voltage inhibit (lvi) on page 173. 1 = lvi enabled during stop mode 0 = lvi disabled during stop mode romsec ? rom security bit romsec enables the rom security feature. setting the romsec bit prevents access to the rom contents. 1 = rom security enabled 0 = rom security disabled lvirst ? lvi reset enable bit lvirst enables the reset signal from the lvi module. see low voltage inhibit (lvi) on page 173 . 1 = lvi module resets enabled 0 = lvi module resets disabled lvipwr ? lvi power enable bit lvipwr enables the lvi module. see low voltage inhibit (lvi) on page 173. 1 = lvi module power enabled 0 = lvi module power disabled bit 7 6 5 4 3 2 1 bit 0 mora $001f read: lvistop romsec lvirst lvipwr ssrec coprs stop copd write: r r rr rrrr reset: unaffected by reset figure 9-1. mask option register a (mora) mask options functional description MC68HC08AZ32A ? rev 1.0 technical data motorola mask options 147 ssrec ? short stop recovery bit ssrec enables the cpu to exit stop mode with a delay of 32 cgmxclk cycles instead of a 4096 cgmxclk cycle delay. 1 = stop mode recovery after 32 cgmxclk cycles 0 = stop mode recovery after 4096 cgmxclk cycles if using an external crystal oscillator, the ssrec bit should not be set. coprs ? cop rate select coprs is similar to copl (please note that the logic is reversed) as it determines the timeout period for the cop. 1 = cop timeout period is 2 13 ? 2 4 cgmxclk cycles. 0 = cop timeout period is 2 18 ? 2 4 cgmxclk cycles. stop ? stop enable bit stop enables the stop instruction. 1 = stop instruction enabled 0 = stop instruction treated as illegal opcode copd ? cop disable bit copd disables the cop module. see computer operating properly (cop) on page 167. 1 = cop module disabled 0 = cop module enabled note: extra care should be taken when selecting mor options since not all hc08 family devices have the same options. in particular refer to the appendix on differences of previous versions of mc68hc08az32. it is the user ? s responsibility to correctly define the mask option registers. mask options technical data MC68HC08AZ32A ? rev 1.0 148 mask options motorola eedivclk ? eeprom timebase divider clock select bit eedivclk selects the reference clock source for the eeprom timebase divider. see eeprom timebase divider register on page 72. 1 = cpu bus clock drives the eeprom timebase divider 0 = cgmxclk drives the eeprom timebase divider eesec ? this read/write bit has no function. 1 = n/a 0 = n/a eemonsec ? eeprom read protection in monitor mode bit when eemonsec is set the entire eeprom aray cannot be acessed in monitor mode unless a valid security code is entered. 1 = eeprom read protection in monitor mode enabled. 0 = eeprom read protection in monitor mode disabled. az32a ? device indicator this bit is used to distinguish a MC68HC08AZ32A from older non- ? a ? suffix versions 1 = ? a ? version 0 = non- ? a ? version extra care should be exercised when selecting mask option registers since other hc08 family parts may have different options. if in doubt, check with your local field applications representative. bit 7 6 5 4 3 2 1 bit 0 morb $fe09 read: eedivclk r e e s e c eemonsec az32a write: rrrr reset: unaffected by reset = unimplemented r = reserved figure 9-2. mask option register b (morb) MC68HC08AZ32A ? rev 1.0 technical data motorola break module 149 technical data ? MC68HC08AZ32A section 10. break module 10.1 contents 10.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 10.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 10.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 10.4.1 flag protection during break interrupts . . . . . . . . . . . . 151 10.4.2 cpu during break interrupts . . . . . . . . . . . . . . . . . . . . . 152 10.4.3 tim and pit during break interrupts . . . . . . . . . . . . . . . 152 10.4.4 cop during break interrupts . . . . . . . . . . . . . . . . . . . . . 152 10.5 break module registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 10.5.1 break status and control register (brkscr) . . . . . . . 153 10.5.2 break address registers (brkh and brkl) . . . . . . . . 154 10.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 10.6.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 10.6.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 10.2 introduction this section describes the break module. the break module can generate a break interrupt which stops normal program flow at a defined address in order to begin execution of a background program. 10.3 features features of the break module include the following: accessible i/o registers during the break interrupt cpu-generated break interrupts break module technical data MC68HC08AZ32A ? rev 1.0 150 break module motorola software-generated break interrupts cop disabling during break interrupts 10.4 functional description when the internal address bus matches the value written in the break address registers, the break module issues a breakpoint signal (bkpt ) to the sim. the sim then causes the cpu to load the instruction register with a software interrupt instruction (swi) after completion of the current cpu instruction. the program counter vectors to $fffc and $fffd ($fefc and $fefd in monitor mode). the following events can cause a break interrupt to occur: a cpu-generated address (the address in the program counter) matches the contents of the break address registers. software writes a ? 1 ? to the brka bit in the break status and control register (brkscr). when a cpu-generated address matches the contents of the break address registers, the break interrupt begins after the cpu completes its current instruction. a return from interrupt instruction (rti) in the break routine ends the break interrupt and returns the mcu to normal operation. figure 10-1 shows the structure of the break module. break module functional description MC68HC08AZ32A ? rev 1.0 technical data motorola break module 151 figure 10-1. break module block diagram 10.4.1 flag protection during break interrupts the system integration module (sim) controls whether or not module status bits can be cleared during the break state. the bcfe bit in the sim break flag control register (sbfcr) enables software to clear status bits during the break state. see system integration module (sim) on page 95, and the break interrupts subsection for each module. iab[15:8] iab[7:0] 8-bit comparator 8-bit comparator control break address register low break address register high iab[15:0] bkpt (to sim) table 10-1. break i/o register summary register name bit 7 6 5 4 3 2 1 bit 0 addr. break address register high (brkh) bit 15 14 13 12 11 10 9 bit 8 $fe0c break address register low (brkl) bit 7 6 5 4 3 2 1 bit 0 $fe0d reak status/control register (brkscr) brke brka 000000 $fe0e = unimplemented break module technical data MC68HC08AZ32A ? rev 1.0 152 break module motorola 10.4.2 cpu during break interrupts the cpu starts a break interrupt by: loading the instruction register with the swi instruction loading the program counter with $fffc:$fffd ($fefc:$fefd in monitor mode) the break interrupt begins after completion of the cpu instruction in progress. if the break address register match occurs on the last cycle of a cpu instruction, the break interrupt begins immediately. 10.4.3 tim and pit during break interrupts a break interrupt stops the timer counter. 10.4.4 cop during break interrupts the cop is disabled during a break interrupt when v hi is present on the rst pin. 10.5 break module registers three registers control and monitor operation of the break module: break status and control register (brkscr) break address register high (brkh) break address register low (brkl) break module break module registers MC68HC08AZ32A ? rev 1.0 technical data motorola break module 153 10.5.1 break status and control register (brkscr) the break status and control register contains break module enable and status bits. brke ? break enable bit this read/write bit enables breaks on break address register matches. brke is cleared by writing a ? 0 ? to bit 7. reset clears the brke bit. 1 = breaks enabled on 16-bit address match 0 = breaks disabled on 16-bit address match brka ? break active bit this read/write status and control bit is set when a break address match occurs. writing a ? 1 ? to brka generates a break interrupt. brka is cleared by writing a ? 0 ? to it before exiting the break routine. reset clears the brka bit. 1 = break address match 0 = no break address match bit 7654321bit 0 brkscr $fe0e read: brke brka 000000 write: reset:00000000 = unimplemented figure 10-2. break status and control register (brkscr) break module technical data MC68HC08AZ32A ? rev 1.0 154 break module motorola 10.5.2 break address registers (brkh and brkl) the break address registers contain the high and low bytes of the desired breakpoint address. reset clears the break address registers. 10.6 low-power modes the wait and stop instructions put the mcu in low-power- consumption standby modes. 10.6.1 wait mode if enabled, the break module is active in wait mode. the sim break wait bit (bw) in the sim break status register indicates whether wait was exited by a break interrupt. if so, the user can modify the return address on the stack by subtracting one from it. (see system integration module (sim) on page 95). 10.6.2 stop mode the break module is inactive in stop mode. the stop instruction does not affect break module register states. bit 7654321bit 0 brkh $fe0c read: bit 15 14 13 12 11 10 9 bit 8 write: reset:00000000 bit 7654321bit 0 brkl $fe0d read: bit 7654321bit 0 write: reset:00000000 figure 10-3. break address registers (brkh and brkl) MC68HC08AZ32A ? rev 1.0 technical data motorola monitor rom (mon) 155 technical data ? MC68HC08AZ32A section 11. monitor rom (mon) 11.1 contents 11.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 11.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 11.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 11.4.1 entering monitor mode . . . . . . . . . . . . . . . . . . . . . . . . . . 158 11.4.2 data format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 11.4.3 echoing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 11.4.4 break signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 11.4.4.1 commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 11.4.5 baud rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 11.4.6 security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 11.2 introduction this section describes the monitor rom (mon08). the monitor rom allows complete testing of the mcu through a single-wire interface with a host computer. 11.3 features features of the monitor rom include the following: normal user-mode pin functionality one pin dedicated to serial communication between monitor rom and host computer standard mark/space non-return-to-zero (nrz) communication with host computer up to 28.8k baud communication with host computer monitor rom (mon) technical data MC68HC08AZ32A ? rev 1.0 156 monitor rom (mon) motorola execution of code in ram or rom eeprom programming rom security (read protection) (1) eeprom read protection (1) 11.4 functional description the monitor rom receives and executes commands from a host computer. figure 11-1 shows a sample circuit used to enter monitor mode and communicate with a host computer via a standard rs-232 interface. while simple monitor commands can access any memory address, the MC68HC08AZ32A has optional rom/eeprom read protection features to prevent external viewing of the contents of rom/eeprom (see mask options on page 145). proper procedures must be followed to verify rom/eeprom content. access to the rom/eeprom is denied to unauthorized users of customer specified software with read protection features enabled. see security on page 164. in monitor mode, the mcu can execute host-computer code in ram while all mcu pins except pta0 retain normal operating mode functions. all communication between the host computer and the mcu is through the pta0 pin. a level-shifting and multiplexing interface is required between pta0 and the host computer. pta0 is used in a wired-or configuration and requires a pull-up resistor. 1. no security feature is absolutely secure. however, motorola ? s strategy is to make reading or copying the rom/eeprom data difficult for unauthorized users monitor rom (mon) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola monitor rom (mon) 157 figure 11-1. monitor mode circuit + + + 10 m ? x1 v dd v dd a mc145407 mc68hc125 68hc08 rst v dd a cgmxfc osc1 osc2 v ss v dd pta0 v dd 10 k ? 0.1 f 0.1 f 6 5 2 4 3 1 db-25 2 3 7 20 18 17 19 16 15 v dd v dd v dd 20 pf 20 pf 10 f 10 f 10 f 10 f 1 2 4 7 14 3 0.1 f 4.9152 mhz 10 k ? ptc3 v dd 10 k ? b a note: position a ? bus clock = cgmxclk 4 or cgmvclk 4 position b ? bus clock = cgmxclk 2 (see note.) 5 6 + v ssa ptc0 ptc1 10 k ? v hi irq 1 k ? 9.1v monitor rom (mon) technical data MC68HC08AZ32A ? rev 1.0 158 monitor rom (mon) motorola 11.4.1 entering monitor mode table 11-1 shows the pin conditions for entering monitor mode. enter monitor mode by either executing a software interrupt instruction (swi) or applying a ? 0 ? and then a ? 1 ? to the rst pin. once out of reset, the mcu waits for the host to send eight security bytes (see security on page 164). after the security bytes, the mcu sends a break signal (10 consecutive ? 0 ? s) to the host computer, indicating that it is ready to receive a command. monitor mode uses alternate vectors for reset, swi, and break interrupt. the alternate vectors are in the $fe page instead of the $ff page and allow code execution from the internal monitor firmware instead of user code. the cop module is disabled in monitor mode as long as v hi (see electrical specifications on page 423), is applied to either the irq pin or the rst pin. see system integration module (sim) on page 95 for more information on modes of operation. note: holding the ptc3 pin low when entering monitor mode causes a bypass of a divide-by-two stage at the oscillator. the cgmout frequency is equal to the cgmxclk frequency, and the osc1 input directly generates internal bus clocks. in this case, the osc1 signal must have a 50% duty cycle at maximum bus frequency. table 11-1. mode selection irq pin ptc0 pin ptc1 pin pta0 pin ptc3 pin mode cgmout bus frequency v hi (1) 1 0 1 1 monitor or v hi (1) 1 0 1 0 monitor cgmxclk 1. for v hi , 5.0 volt dc electrical characteristics on page 426, and maximum ratings on page 424. cgmxclk 2 ----------------------------- cgmvclk 2 ----------------------------- cgmout 2 -------------------------- cgmout 2 -------------------------- monitor rom (mon) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola monitor rom (mon) 159 table 11-2 is a summary of the differences between user mode and monitor mode. 11.4.2 data format communication with the monitor rom is in standard non-return-to-zero (nrz) mark/space data format. (see figure 11-2 and figure 11-3 ). figure 11-2. monitor data format figure 11-3. sample monitor waveforms the data transmit and receive rate can be anywhere up to 28.8 kbaud. transmit and receive baud rates must be identical. table 11-2. mode differences modes functions cop reset vector high reset vector low break vector high break vector low swi vector high swi vector low user enabled $fffe $ffff $fffc $fffd $fffc $fffd monitor disabled (1) $fefe $feff $fefc $fefd $fefc $fefd 1. if the high voltage (v hi ) is removed from the irq and/or reset pin while in monitor mode, the sim as- serts its cop enable output. the cop is enabled or disabled by the copd bit in the configuration reg- ister. see 5.0 volt dc electrical characteristics on page 426. bit 5 start bit bit 0 bit 1 next stop bit start bit bit 2 bit 3 bit 4 bit 6 bit 7 bit 5 start bit bit 0 bit 1 next stop bit start bit bit 2 bit 3 bit 4 bit 6 bit 7 start bit bit 0 bit 1 next stop bit start bit bit 2 $a5 break bit 3 bit 4 bit 5 bit 6 bit 7 monitor rom (mon) technical data MC68HC08AZ32A ? rev 1.0 160 monitor rom (mon) motorola 11.4.3 echoing the monitor rom immediately echoes each received byte back to the pta0 pin for error checking, as shown in figure 11-4 . figure 11-4. read transaction any result of a command appears after the echo of the last byte of the command. 11.4.4 break signal a break signal is a start bit followed by nine low bits. this is shown in figure 11-4 . when the monitor receives a break signal, it drives the pta0 pin high for the duration of two bits before echoing the break signal. addr. high read read addr. high addr. low addr. low data echo sent to monitor result figure 11-5. break transaction 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 missing stop bit two-stop-bit delay before zero echo monitor rom (mon) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola monitor rom (mon) 161 11.4.4.1 commands the monitor rom uses the following commands: read (read memory) write (write memory) iread (indexed read) iwrite (indexed write) readsp (read stack pointer) run (run user program) table 11-3. read (read memory) command description read byte from memory operand specifies 2-byte address in high byte:low byte order data returned returns contents of specified address opcode $4a command sequence addr. high read read addr. high addr. low addr. low data echo sent to monitor result table 11-4. write (write memory) command description write byte to memory operand specifies 2-byte address in high byte:low byte order; low byte followed by data byte data returned none opcode $49 command sequence addr. high write write addr. high addr. low addr. low data echo sent to monitor data monitor rom (mon) technical data MC68HC08AZ32A ? rev 1.0 162 monitor rom (mon) motorola table 11-5. iread (indexed read) command description read next 2 bytes in memory from last address accessed operand specifies 2-byte address in high byte:low byte order data returned returns contents of next two addresses opcode $1a command sequence table 11-6. iwrite (indexed write) command description write to last address accessed + 1 operand specifies single data byte data returned none opcode $19 command sequence data iread iread data echo sent to monitor result data iwrite iwrite data echo sent to monitor monitor rom (mon) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola monitor rom (mon) 163 a sequence of iread or iwrite commands can sequentially access a block of memory over the full 64k byte memory map. 11.4.5 baud rate the MC68HC08AZ32A features a monitor mode which is optimised to operate with either a 4.9152mhz crystal clock source (or multiples of 4.9152mhz) or a 4mhz crystal (or multiples of 4mhz). this supports designs which use the mscan08 module, which is generally clocked from a 4mhz, 8mhz or 16mhz internal reference clock. the table below table 11-7. readsp (read stack pointer) command description reads stack pointer operand none data returned returns stack pointer in high byte:low byte order opcode $0c command sequence table 11-8. run (run user program) command description executes rti instruction operand none data returned none opcode $28 command sequence sp high readsp readsp sp low echo sent to monitor result run run echo sent to monitor monitor rom (mon) technical data MC68HC08AZ32A ? rev 1.0 164 monitor rom (mon) motorola outlines the available baud rates for a range of crystals and how they can match to a pc baud rate. care should be taken when setting the baud rate since incorrect baud rate setting can result in communications failure. 11.4.6 security security features discourage unauthorized reading of rom/eeprom locations while in monitor mode. the host can bypass the security features at monitor mode entry by sending eight security bytes that match the byte locations $fff6 ? $fffd. locations $fff6 ? $fffd contain user-defined data. note: do not leave locations $fff6 ? $fffd blank. for security reasons, enter data at locations $fff6 ? $fffd even if they are not used for vectors. during monitor mode entry, the mcu waits after the power-on reset for the host to send the eight security bytes on pin pa0. if the received bytes match those at locations $fff6 ? $fffd, the host bypasses the security features and can read all rom/eeprom locations and execute code from rom. security remains bypassed until a power-on reset occurs. after the host bypasses security, any reset other than a power-on reset requires the host to send another eight baud rate closest pc baud pc error % clock freq ptc3=0 ptc3=1 ptc3=0 ptc3=1 ptc3=0 ptc3=1 32khz 57.97 28.98 57.6 28.8 0.64 0.63 1mhz 1811.59 905.80 1800 900 0.64 0.64 2mhz 3623.19 1811.59 3600 1800 0.64 0.64 4mhz 7246.37 3623.19 7200 3600 0.64 0.64 4.194mhz 7597.83 3798.91 7680 3840 1.08 1.08 4.9152mhz 8904.35 4452.17 8861 4430 0.49 0.50 8mhz 14492.72 7246.37 14400 7200 0.64 0.64 16mhz 28985.51 14492.75 28800 14400 0.64 0.64 monitor rom (mon) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola monitor rom (mon) 165 bytes. if the reset was not a power-on reset, security remains bypassed regardless of the data that the host sends. if the received bytes do not match the data at locations $fff6 ? $fffd, the host fails to bypass the security features. the mcu remains in monitor mode, but reading rom/eeprom locations returns undefined data, and trying to execute code from rom causes an illegal address reset. after the host fails to bypass security, any reset other than a power-on reset causes an endless loop of illegal address resets. after receiving the eight security bytes from the host, the mcu transmits a break character signalling that it is ready to receive a command. note: the mcu does not transmit a break character until after the host sends the eight security bytes. figure 11-6. monitor mode entry timing byte 1 byte 1 echo byte 2 byte 2 echo byte 8 byte 8 echo command command echo pa0 rst v dd 4096 + 32 cgmxclk cycles 24 bus cycles (minimum) 1 4 1 1 2 1 break note: 1 = echo delay (2 bit times) 2 = data return delay (2 bit times) 4 = wait 1 bit time before sending next byte. 4 from host from mcu monitor rom (mon) technical data MC68HC08AZ32A ? rev 1.0 166 monitor rom (mon) motorola MC68HC08AZ32A ? rev 1.0 technical data motorola computer operating properly (cop) 167 technical data ? MC68HC08AZ32A section 12. computer operating properly (cop) 12.1 contents 12.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 12.3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 12.4 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 12.4.1 cgmxclk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 12.4.2 stop instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 12.4.3 copctl write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 12.4.4 power-on reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 12.4.5 internal reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 12.4.6 reset vector fetch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 12.4.7 copd (cop disable) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 12.4.8 coprs (cop rate select) . . . . . . . . . . . . . . . . . . . . . . . . 170 12.5 cop control register (copctl) . . . . . . . . . . . . . . . . . . . . . 171 12.6 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 12.7 monitor mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 12.8 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 12.8.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 12.8.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 12.9 cop module during break interrupts . . . . . . . . . . . . . . . . . 172 12.2 introduction this section describes the computer operating properly (cop) module, a free-running counter that generates a reset if allowed to overflow. the cop module helps software recover from runaway code. cop resets can be prevented by periodically clearing the cop counter. computer operating properly (cop) technical data MC68HC08AZ32A ? rev 1.0 168 computer operating properly (cop) motorola 12.3 functional description figure 12-1 shows the structure of the cop module. figure 12-1. cop block diagram the cop counter is a free-running 6-bit counter preceded by a12-bit prescaler. if not cleared by software, the cop counter overflows and generates an asynchronous reset after 2 13 ? 2 4 , or 2 18 ? 2 4 cgmxclk cycles, depending on the state of the cop rate select bit, coprs in table 12-1. cop i/o register summary register name bit 7654321bit 0addr. cop control register (copctl) $ffff copctl write cgmxclk reset vector fetch reset reset status internal reset sources stop instruction clear stages 4 ? 12 clear all stages 6-bit cop counter copd from mora reset copctl write clear cop counter coprs from mora 12-bit cop prescaler register computer operating properly (cop) i/o signals MC68HC08AZ32A ? rev 1.0 technical data motorola computer operating properly (cop) 169 mora. when coprs = 0, a 4.9152 mhz crystal, gives a cop timeout period of 53.3ms. writing any value to location $ffff before overflow occurs prevents a cop reset by clearing the cop counter and stages 4 through 12 of the prescaler. note: service the cop immediately after reset and before entering or after exiting stop mode to guarantee the maximum time before the first cop counter overflow. a cop reset pulls the rst pin low for 32 cgmxclk cycles and sets the cop bit in the sim reset status register (srsr). see sim reset status register (srsr) on page 114. in monitor mode, the cop is disabled if the rst pin or the irq pin is held at v hi . during the break state, v hi on the rst pin disables the cop. note: place cop clearing instructions in the main program and not in an interrupt subroutine. such an interrupt subroutine could keep the cop from generating a reset even while the main program is not working properly. 12.4 i/o signals the following paragraphs describe the signals shown in figure 12-1 . 12.4.1 cgmxclk cgmxclk is the crystal oscillator output signal. the cgmxclk frequency is equal to the crystal frequency. 12.4.2 stop instruction the stop instruction clears the cop prescaler. computer operating properly (cop) technical data MC68HC08AZ32A ? rev 1.0 170 computer operating properly (cop) motorola 12.4.3 copctl write writing any value to the cop control register (copctl) (see cop control register (copctl) on page 171), clears the cop counter and clears bits 12 ? 4 of the cop prescaler. reading the cop control register returns the reset vector. 12.4.4 power-on reset the power-on reset (por) circuit clears the cop prescaler 4096 cgmxclk cycles after power-up. 12.4.5 internal reset an internal reset clears the cop prescaler and the cop counter. 12.4.6 reset vector fetch a reset vector fetch occurs when the vector address appears on the data bus. a reset vector fetch clears the cop prescaler. 12.4.7 copd (cop disable) the copd signal reflects the state of the cop disable bit (copd) in the mask option register (mora). see mask options on page 145. 12.4.8 coprs (cop rate select) the coprs signal reflects the state of the cop rate select bit, coprs in the mora register (see figure 9-1 on page 146). computer operating properly (cop) cop control register (copctl) MC68HC08AZ32A ? rev 1.0 technical data motorola computer operating properly (cop) 171 12.5 cop control register (copctl) the cop control register is located at address $ffff and overlaps the reset vector. writing any value to $ffff clears the cop counter and starts a new timeout period. reading location $ffff returns the low byte of the reset vector. 12.6 interrupts the cop does not generate cpu interrupt requests. 12.7 monitor mode the cop is disabled in monitor mode when v hi is present on the irq pin or on the rst pin. 12.8 low-power modes the wait and stop instructions put the mcu in low-power- consumption standby modes. 12.8.1 wait mode the cop continues to operate during wait mode. to prevent a cop reset during wait mode, the cop counter should be cleared periodically in a cpu interrupt routine. bit 7654321bit 0 copctl $ffff read: low byte of reset vector write: clear cop counter reset: unaffected by reset figure 12-2. cop control register (copctl) computer operating properly (cop) technical data MC68HC08AZ32A ? rev 1.0 172 computer operating properly (cop) motorola 12.8.2 stop mode stop mode turns off the cgmxclk input to the cop and clears the cop prescaler. the cop should be serviced immediately before entering or after exiting stop mode to ensure a full cop timeout period after entering or exiting stop mode. the stop bit in the mask option register (mor) enables the stop instruction. to prevent inadvertently turning off the cop with a stop instruction, the stop instruction should be disabled by programming the stop bit to ? 0 ? . 12.9 cop module during break interrupts the cop is disabled during a break interrupt when v hi is present on the rst pin. MC68HC08AZ32A ? rev 1.0 technical data motorola low voltage inhibit (lvi) 173 technical data ? MC68HC08AZ32A section 13. low voltage inhibit (lvi) 13.1 contents 13.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 13.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 13.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 13.4.1 polled lvi operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 13.4.2 forced reset operation . . . . . . . . . . . . . . . . . . . . . . . . . . 175 13.4.3 false reset protection . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 13.5 lvi status register (lvisr) . . . . . . . . . . . . . . . . . . . . . . . . . 176 13.6 lvi interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 13.7 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 13.7.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 13.7.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 13.2 introduction this section describes the low-voltage inhibit module, which monitors the voltage on the v dd pin and can force a reset when the v dd voltage falls to the lvi trip voltage. 13.3 features features of the lvi module include the following: programmable lvi reset programmable power consumption digital filtering of vdd pin level low voltage inhibit (lvi) technical data MC68HC08AZ32A ? rev 1.0 174 low voltage inhibit (lvi) motorola note: if a low voltage interrupt (lvi) occurs during programming of eeprom memory, then adequate programming time may not have been allowed to ensure the integrity and retention of the data. it is the responsibility of the user to ensure that in the event of an lvi any addresses being programmed receive specification programming conditions. 13.4 functional description figure 13-1 shows the structure of the lvi module. the lvi is enabled out of reset. the lvi module contains a bandgap reference circuit and comparator. the lvi power bit, lvipwr, enables the lvi to monitor v dd voltage. the lvi reset bit, lvirst, enables the lvi module to generate a reset when v dd falls below a voltage, lvi tripf , and remains at or below that level for 9 or more consecutive cpu cycles. note that short v dd spikes may not trip the lvi. it is the user ? s responsibility to ensure a clean v dd signal within the specified operating voltage range if normal microcontroller operation is to be guaranteed. lvistop enables the lvi module during stop mode. this will ensure when the stop instruction is implemented the lvi will continue to monitor the voltage level on v dd . lvipwr, lvirst and lvistop are mask options. see mask options on page 145. once an lvi reset occurs, the mcu remains in reset until v dd rises above a voltage, lvi tripr . v dd must be above lvi tripr for only one cpu cycle to bring the mcu out of reset. the output of the comparator controls the state of the lviout flag in the lvi status register (lvisr). low voltage inhibit (lvi) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola low voltage inhibit (lvi) 175 an lvi reset also drives the rst pin low to provide low-voltage protection to external peripheral devices. figure 13-1. lvi module block diagram 13.4.1 polled lvi operation in applications that can operate at v dd levels below the lvi tripf level, software can monitor v dd by polling the lviout bit. in the mask option register, the lvipwr bit must be at logic ? 1 ? to enable the lvi module and the lvirst bit must be at logic ? 0 ? to disable lvi resets. 13.4.2 forced reset operation in applications that require v dd to remain above the lvi tripf level, enabling lvi resets allows the lvi module to reset the mcu when v dd falls to the lvi tripf level and remains at or below that level for 9 or more consecutive cpu cycles. in the mask option register, the lvipwr and table 13-1. lvi i/o register summary register name bit 7654321bit 0addr. lvi status register (lvisr) lviout $fe0f = unimplemented low v dd lvirst v dd > lvi trip = 0 v dd < lvi trip = 1 lviout lvipwr detector v dd lvi reset from mora from mora v dd digital filter cpu clock anlgtrip stop mode filter bypass lvistop from mora low voltage inhibit (lvi) technical data MC68HC08AZ32A ? rev 1.0 176 low voltage inhibit (lvi) motorola lvirst bits must be at ? 1 ? to enable the lvi module and to enable lvi resets. 13.4.3 false reset protection the v dd pin level is digitally filtered to reduce false resets due to power supply noise. in order for the lvi module to reset the mcu,v dd must remain at or below the lvi tripf level for 9 or more consecutive cpu cycles. v dd must be above lvi tripr for only one cpu cycle to bring the mcu out of reset. 13.5 lvi status register (lvisr) the lvi status register flags v dd voltages below the lvi tripf level . lviout ? lvi output bit this read-only flag becomes set when v dd falls below the lvi tripf voltage for 32-40 cgmxclk cycles. (see table 13-2 ). reset clears the lviout bit. bit 7654321bit 0 lvisr $fe0f read: lviout0000000 write: reset:00000000 = unimplemented figure 13-2. lvi status register (lvisr) low voltage inhibit (lvi) lvi interrupts MC68HC08AZ32A ? rev 1.0 technical data motorola low voltage inhibit (lvi) 177 13.6 lvi interrupts the lvi module does not generate interrupt requests. 13.7 low-power modes the wait instruction puts the mcu in low-power-consumption standby mode. 13.7.1 wait mode when the lvipwr mask option is programmed to ? 1 ? , the lvi module is active after a wait instruction. when the lvirst mask option is programmed to ? 1 ? , the lvi module can generate a reset and bring the mcu out of wait mode. table 13-2. lviout bit indication v dd lviout at level: for number of cgmxclk cycles: v dd > lvi tripr any 0 v dd < lvi tripf < 32 cgmxclk cycles 0 v dd < lvi tripf between 32 & 40 cgmxclk cycles 0 or 1 v dd < lvi tripf > 40 cgmxclk cycles 1 lvi tripf < v dd < lvi tripr any previous value low voltage inhibit (lvi) technical data MC68HC08AZ32A ? rev 1.0 178 low voltage inhibit (lvi) motorola 13.7.2 stop mode with lvistop=1 and lvipwr=1 in the mora register, the lvi module will be active after a stop instruction. because cpu clocks are disabled during stop mode, the lvi trip must bypass the digital filter to generate a reset and bring the mcu out of stop. with the lvipwr bit in the mora register at a logic 1 and the lvistop bit at a logic 0, the lvi module will be inactive after a stop instruction. note that the lvi feature is intended to provide the safe shutdown of the microcontroller and thus protection of related circuitry prior to any application v dd voltage collapsing completely to an unsafe level. is is not intended that users operate the microcontroller at lower than the specified operating voltage, v dd . MC68HC08AZ32A ? rev 1.0 technical data motorola external interrupt module (irq) 179 technical data ? MC68HC08AZ32A section 14. external interrupt module (irq) 14.1 contents 14.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 14.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 14.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 14.4.1 irq pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 14.5 irq module during break interrupts . . . . . . . . . . . . . . . . . 184 14.6 irq status and control register (iscr) . . . . . . . . . . . . . . . 184 14.2 introduction the irq module provides the nonmaskable interrupt input. 14.3 features features of the irq module include the following: dedicated external interrupt pins (irq ) irq interrupt control bit hysteresis buffer programmable edge-only or edge and level interrupt sensitivity automatic interrupt acknowledge external interrupt module (irq) technical data MC68HC08AZ32A ? rev 1.0 180 external interrupt module (irq) motorola 14.4 functional description a ? 0 ? applied to any of the external interrupt pins can latch a cpu interrupt request. figure 14-1 shows the structure of the irq module. interrupt signals on the irq pin are latched into the irq latch. an interrupt latch remains set until one of the following occurs: vector fetch ? a vector fetch automatically generates an interrupt acknowledge signal which clears the latch that caused the vector fetch. software clear ? software can clear an interrupt latch by writing to the appropriate acknowledge bit in the interrupt status and control register (iscr). writing a logic ? 1 ? to the ack bit clears the irq latch. reset ? a reset automatically clears the interrupt latch. figure 14-1. irq module block diagram the external interrupt pin is falling-edge-triggered and is software- configurable to be both falling-edge and low-level-triggered. the mode bit in the iscr controls the triggering sensitivity of the irq pin. ack imask dq ck clr irq high interrupt to mode select logic irq latch request irq v dd mode voltage detect synchro- nizer irqf to cpu for bil/bih instructions vector fetch decoder internal address bus external interrupt module (irq) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola external interrupt module (irq) 181 when an interrupt pin is edge-triggered only, the interrupt latch remains set until a vector fetch, software clear, or reset occurs. when an interrupt pin is both falling-edge and low-level-triggered, the interrupt latch remains set until both of the following occur: vector fetch or software clear return of the interrupt pin to ? 1 ? the vector fetch or software clear may occur before or after the interrupt pin returns to ? 1 ? . as long as the pin is low, the interrupt request remains pending. a reset will clear the latch and the mode control bit, thereby clearing the interrupt even if the pin stays low. when set, the imask bit in the iscr masks all external interrupt requests. a latched interrupt request is not presented to the interrupt priority logic unless the corresponding imask bit is clear. note: the interrupt mask (i) in the condition code register (ccr) masks all interrupt requests, including external interrupt requests. see figure 14- 2 . table 14-1. irq i/o register summary register name bit 7 6 5 4 3 2 1 bit 0 addr. irq status/control register (iscr) read: 0 0 0 0 irqf 0 imask mode $001a write:rrrrrack r= reserved external interrupt module (irq) technical data MC68HC08AZ32A ? rev 1.0 182 external interrupt module (irq) motorola . figure 14-2. irq interrupt flowchart from reset i bit set? fetch next yes no interrupt? instruction. swi instruction? rti instruction? no stack cpu registers. no set i bit. load pc with interrupt vector. no yes unstack cpu registers. execute instruction. yes yes external interrupt module (irq) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola external interrupt module (irq) 183 14.4.1 irq pin a ? 0 ? on the irq pin can latch an interrupt request into the irq latch. a vector fetch, software clear, or reset clears the irq latch. if the mode bit is set, the irq pin is both falling-edge-sensitive and low- level-sensitive. with mode set, both of the following actions must occur to clear the irq latch: vector fetch or software clear ? a vector fetch generates an interrupt acknowledge signal to clear the latch. software may generate the interrupt acknowledge signal by writing a logic ? 1 ? to the ack bit in the interrupt status and control register (iscr). the ack bit is useful in applications that poll the irq pin and require software to clear the irq latch. writing to the ack bit can also prevent spurious interrupts due to noise. setting ack does not affect subsequent transitions on the irq pin. a falling edge that occurs after writing to the ack bit latches another interrupt request. if the irq mask bit, imask, is clear, the cpu loads the program counter with the vector address at locations $fffa and $fffb. return of the irq pin to logic ? 1 ? ? as long as the irq pin is at logic ? 0 ? , the irq latch remains set. the vector fetch or software clear and the return of the irq pin to logic ? 1 ? may occur in any order. the interrupt request remains pending as long as the irq pin is at logic ? 0 ? . a reset will clear the latch and the mode control bit, thereby clearing the interrupt even if the pin stays low. if the mode bit is clear, the irq pin is falling-edge-sensitive only. with mode clear, a vector fetch or software clear immediately clears the irq latch. the irqf bit in the iscr register can be used to check for pending interrupts. the irqf bit is not affected by the imask bit, which makes it useful in applications where polling is preferred. the bih or bil instruction is used to read the logic level on the irq pin. note: when using the level-sensitive interrupt trigger, false interrupts can be avoided by masking interrupt requests in the interrupt routine. external interrupt module (irq) technical data MC68HC08AZ32A ? rev 1.0 184 external interrupt module (irq) motorola 14.5 irq module during break interrupts the system integration module (sim) controls whether the irq interrupt latch can be cleared during the break state. the bcfe bit in the sim break flag control register (sbfcr) enables software to clear the latches during the break state. see sim break flag control register (sbfcr) on page 115. to allow software to clear the irq latch during a break interrupt, write a logic ? 1 ? to the bcfe bit. if a latch is cleared during the break state, it remains cleared when the mcu exits the break state. to protect the latches during the break state, write a logic ? 0 ? to the bcfe bit. with bcfe at logic ? 0 ? (its default state), writing to the ack bit in the irq status and control register during the break state has no effect on the irq latch. 14.6 irq status and control register (iscr) the irq status and control register (iscr) controls and monitors operation of the irq module. the iscr performs the following functions: indicates the state of the irq interrupt flag clears the irq interrupt latch masks irq interrupt requests controls triggering sensitivity of the irq interrupt pin address: $001a bit 7654321bit 0 read: 0000irqf0 imask mode write:rrrrrack reset:00000000 r= reserved figure 14-3. irq status and control register (iscr) external interrupt module (irq) irq status and control register (iscr) MC68HC08AZ32A ? rev 1.0 technical data motorola external interrupt module (irq) 185 irqf ? irq flag bit this read-only status bit is high when the irq interrupt is pending. 1 = irq interrupt pending 0 = irq interrupt not pending ack ? irq interrupt request acknowledge bit writing a logic ? 1 ? to this write-only bit clears the irq latch. ack always reads as logic ? 0 ? . reset clears ack. imask ? irq interrupt mask bit writing a logic ? 1 ? to this read/write bit disables irq interrupt requests. reset clears imask. 1 = irq interrupt requests disabled 0 = irq interrupt requests enabled mode ? irq edge/level select bit this read/write bit controls the triggering sensitivity of the irq pin. reset clears mode. 1 = irq interrupt requests on falling edges and low levels 0 = irq interrupt requests on falling edges only external interrupt module (irq) technical data MC68HC08AZ32A ? rev 1.0 186 external interrupt module (irq) motorola MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 187 technical data ? MC68HC08AZ32A section 15. serial communications interface (sci) 15.1 contents 15.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 15.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 15.4 pin name conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 15.5 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 15.5.1 data format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 15.5.2 transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 15.5.2.1 character length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 15.5.2.2 character transmission . . . . . . . . . . . . . . . . . . . . . . . 192 15.5.2.3 break characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 15.5.2.4 idle characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 15.5.2.5 inversion of transmitted output . . . . . . . . . . . . . . . . 197 15.5.2.6 transmitter interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 197 15.5.3 receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 15.5.3.1 character length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 15.5.3.2 character reception . . . . . . . . . . . . . . . . . . . . . . . . . . 200 15.5.3.3 data sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 15.5.3.4 framing errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 15.5.3.5 baud rate tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . 203 15.5.3.6 receiver wakeup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 15.5.3.7 receiver interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 15.5.3.8 error interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 15.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 15.6.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 15.6.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 15.7 sci during break module interrupts . . . . . . . . . . . . . . . . . . 208 15.8 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 15.8.1 pte0/txd (transmit data) . . . . . . . . . . . . . . . . . . . . . . . . 209 15.8.2 pte1/rxd (receive data) . . . . . . . . . . . . . . . . . . . . . . . . 209 serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 188 serial communications interface (sci) motorola 15.9 i/o registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 15.9.1 sci control register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 15.9.2 sci control register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 15.9.3 sci control register 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 15.9.4 sci status register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217 15.9.5 sci status register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 15.9.6 sci data register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 15.9.7 sci baud rate register . . . . . . . . . . . . . . . . . . . . . . . . . . 223 15.2 introduction the sci allows asynchronous communications with peripheral devices and other mcus. 15.3 features the sci module ? s features include: full duplex operation standard mark/space non-return-to-zero (nrz) format 32 programmable baud rates programmable 8-bit or 9-bit character length separately enabled transmitter and receiver separate receiver and transmitter cpu interrupt requests programmable transmitter output polarity two receiver wakeup methods: ? idle line wakeup ? address mark wakeup interrupt-driven operation with eight interrupt flags: ? transmitter empty ? transmission complete ? receiver full serial communications interface (sci) pin name conventions MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 189 ? idle receiver input ? receiver overrun ? noise error ? framing error ? parity error receiver framing error detection hardware parity checking 1/16 bit-time noise detection 15.4 pin name conventions the generic names of the sci input/output (i/o) pins are: rxd (receive data) txd (transmit data) sci i/o lines are implemented by sharing parallel i/o port pins. the full name of an sci input or output reflects the name of the shared port pin. table 15-1 shows the full names and the generic names of the sci i/o pins.the generic pin names appear in the text of this section. 15.5 functional description figure 15-1 shows the structure of the sci module. the sci allows full- duplex, asynchronous, nrz serial communication between the mcu and remote devices, including other mcus. the transmitter and receiver of the sci operate independently, although they use the same baud rate generator. during normal operation, the cpu monitors the status of the sci, writes the data to be transmitted, and processes received data. table 15-1. pin name conventions generic pin names rxd txd full pin names pte1/rxd pte0/txd serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 190 serial communications interface (sci) motorola figure 15-1. sci module block diagram scte tc scrf idle or nf fe pe sctie tcie scrie ilie te re rwu sbk r8 t8 orie feie peie bkf rpf sci data receive shift register sci data register transmit shift register neie m wake ilty flag control transmit control receive control data selection control wakeup pty pen register transmitter interrupt control receiver interrupt control error interrupt control control ensci loops ensci internal bus txinv loops 4 16 pre- scaler baud rate generator cgmxclk rxd txd serial communications interface (sci) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 191 15.5.1 data format the sci uses the standard non-return-to-zero mark/space data format illustrated in figure 15-3 . register name bit 7654321bit 0 sci control register 1 (scc1) read: loops ensci txinv m wake ilty pen pty write: reset:00000000 sci control register 2 (scc2) read: sctie tcie scrie ilie te re rwu sbk write: reset:00000000 sci control register 3 (scc3) read: r8 t8 r r orie neie feie peie write: reset:uu000000 sci status register 1 (scs1) read: scte tc scrf idle or nf fe pe write: reset:11000000 sci status register 2 (scs2) read: 000000bkfrpf write: reset:00000000 sci data register (scdr) read: r7 r6 r5 r4 r3 r2 r1 r0 write: t7 t6 t5 t4 t3 t2 t1 t0 reset: unaffected by reset sci baud rate register (scbr) read: 0 0 scp1 scp0 r scr2 scr1 scr0 write: reset:00000000 = unimplemented u = unaffected r = reserved figure 15-2. sci i/o register summary table 15-2. sci i/o register address summary register scc1 scc2 scc3 scs1 scs2 scdr scbr address $0013 $0014 $0015 $0016 $0017 $0018 $0019 serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 192 serial communications interface (sci) motorola figure 15-3. sci data formats 15.5.2 transmitter figure 15-4 shows the structure of the sci transmitter. 15.5.2.1 character length the transmitter can accommodate either 8-bit or 9-bit data. the state of the m bit in sci control register 1 (scc1) determines character length. when transmitting 9-bit data, bit t8 in sci control register 3 (scc3) is the ninth bit (bit 8). 15.5.2.2 character transmission during an sci transmission, the transmit shift register shifts a character out to the txd pin. the sci data register (scdr) is the write-only buffer between the internal data bus and the transmit shift register. to initiate an sci transmission: 1. enable the sci by writing a logic 1 to the enable sci bit (ensci) in sci control register 1 (scc1). 2. enable the transmitter by writing a logic 1 to the transmitter enable bit (te) in sci control register 2 (scc2). 3. clear the sci transmitter empty bit (scte) by first reading sci status register 1 (scs1) and then writing to the scdr. 4. repeat step 3 for each subsequent transmission. at the start of a transmission, transmitter control logic automatically loads the transmit shift register with a preamble of logic 1s. after the bit 5 start bit bit 0 bit 1 next stop bit start bit 8-bit data format (bit m in scc1 clear) start bit bit 0 next stop bit start bit 9-bit data format (bit m in scc1 set) bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 2 bit 3 bit 4 bit 6 bit 7 parity or data bit parity or data bit serial communications interface (sci) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 193 preamble shifts out, control logic transfers the scdr data into the transmit shift register. a logic 0 start bit automatically goes into the least significant bit position of the transmit shift register. a logic 1 stop bit goes into the most significant bit position. the sci transmitter empty bit, scte, in scs1 becomes set when the scdr transfers a byte to the transmit shift register. the scte bit indicates that the scdr can accept new data from the internal data bus. if the sci transmit interrupt enable bit, sctie, in scc2 is also set, the scte bit generates a transmitter cpu interrupt request. when the transmit shift register is not transmitting a character, the txd pin goes to the idle condition, logic 1. if at any time software clears the ensci bit in sci control register 1 (scc1), the transmitter and receiver relinquish control of the port e pins. serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 194 serial communications interface (sci) motorola figure 15-4. sci transmitter pen pty h876543210l 11-bit transmit stop start t8 scte sctie tcie sbk tc cgmxclk parity generation msb sci data register load from scdr shift enable preamble (all ones) break (all zeros) transmitter control logic shift register tc sctie tcie scte transmitter cpu interrupt request m ensci loops te txinv internal bus 4 pre- scaler scp1 scp0 scr2 scr1 scr0 baud divider 16 txd serial communications interface (sci) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 195 register name bit 7654321bit 0 sci control register 1 (scc1) read: loops ensci txinv m wake ilty pen pty write: reset:00000000 sci control register 2 (scc2) read: sctie tcie scrie ilie te re rwu sbk write: reset:00000000 sci control register 3 (scc3) read: r8 t8 r r orie neie feie peie write: reset:uu000000 sci status register 1 (scs1) read: scte tc scrf idle or nf fe pe write: reset:11000000 sci data register (scdr) read: r7 r6 r5 r4 r3 r2 r1 r0 write: t7 t6 t5 t4 t3 t2 t1 t0 reset: unaffected by reset sci baud rate register (scbr) read: 0 0 scp1 scp0 r scr2 scr1 scr0 write: reset:00000000 = unimplemented u = unaffected r = reserved figure 15-5. sci transmitter i/o register summary table 15-3. sci transmitter i/o address summary register scc1 scc2 scc3 scs1 scdr scbr address $0013 $0014 $0015 $0016 $0018 $0019 serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 196 serial communications interface (sci) motorola 15.5.2.3 break characters writing a logic 1 to the send break bit, sbk, in scc2 loads the transmit shift register with a break character. a break character contains all logic 0s and has no start, stop, or parity bit. break character length depends on the m bit in scc1. as long as sbk is at logic 1, transmitter logic continuously loads break characters into the transmit shift register. after software clears the sbk bit, the shift register finishes transmitting the last break character and then transmits at least one logic 1. the automatic logic 1 at the end of a break character guarantees the recognition of the start bit of the next character. the sci recognizes a break character when a start bit is followed by eight or nine logic 0 data bits and a logic 0 where the stop bit should be. receiving a break character has the following effects on sci registers: sets the framing error bit (fe) in scs1 sets the sci receiver full bit (scrf) in scs1 clears the sci data register (scdr) clears the r8 bit in scc3 sets the break flag bit (bkf) in scs2 may set the overrun (or), noise flag (nf), parity error (pe), or reception in progress flag (rpf) bits 15.5.2.4 idle characters an idle character contains all logic 1s and has no start, stop, or parity bit. idle character length depends on the m bit in scc1. the preamble is a synchronizing idle character that begins every transmission. if the te bit is cleared during a transmission, the txd pin becomes idle after completion of the transmission in progress. clearing and then setting the te bit during a transmission queues an idle character to be sent after the character currently being transmitted. note: when a break sequence is followed immediately by an idle character, this sci design exhibits a condition in which the break character length is reduced by one half bit time. in this instance, the break sequence will serial communications interface (sci) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 197 consist of a valid start bit, eight or nine data bits (as defined by the m bit in scc1) of logic 0 and one half data bit length of logic 0 in the stop bit position followed immediately by the idle character. to ensure a break character of the proper length is transmitted, always queue up a byte of data to be transmitted while the final break sequence is in progress. note: when queueing an idle character, return the te bit to logic 1 before the stop bit of the current character shifts out to the txd pin. setting te after the stop bit appears on txd causes data previously written to the scdr to be lost. a good time to toggle the te bit for a queued idle character is when the scte bit becomes set and just before writing the next byte to the scdr. 15.5.2.5 inversion of transmitted output the transmit inversion bit (txinv) in sci control register 1 (scc1) reverses the polarity of transmitted data. all transmitted values, including idle, break, start, and stop bits, are inverted when txinv is at logic 1. (see 15.9.1 sci control register 1 .) 15.5.2.6 transmitter interrupts the following conditions can generate cpu interrupt requests from the sci transmitter: sci transmitter empty (scte) ? the scte bit in scs1 indicates that the scdr has transferred a character to the transmit shift register. scte can generate a transmitter cpu interrupt request. setting the sci transmit interrupt enable bit, sctie, in scc2 enables the scte bit to generate transmitter cpu interrupt requests. transmission complete (tc) ? the tc bit in scs1 indicates that the transmit shift register and the scdr are empty and that no break or idle character has been generated. the transmission complete interrupt enable bit, tcie, in scc2 enables the tc bit to generate transmitter cpu interrupt requests. serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 198 serial communications interface (sci) motorola 15.5.3 receiver figure 15-6 shows the structure of the sci receiver. figure 15-6. sci receiver block diagram all ones all zeros m wake ilty pen pty bkf rpf h876543210l 11-bit receive shift register stop start data recovery or orie nf neie fe feie pe peie scrie scrf ilie idle wakeup logic parity checking msb error cpu interrupt request cpu interrupt request sci data register r8 orie neie feie peie scrie ilie rwu scrf idle or nf fe pe internal bus pre- scaler baud divider 4 16 scp1 scp0 scr2 scr1 scr0 cgmxclk rxd serial communications interface (sci) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 199 register name bit 7654321bit 0 sci control register 1 (scc1) read: loops ensci txinv m wake ilty pen pty write: reset:00000000 sci control register 2 (scc2) read: sctie tcie scrie ilie te re rwu sbk write: reset:00000000 sci control register 3 (scc3) read: r8 t8 r r orie neie feie peie write: reset:uu000000 sci status register 1 (scs1) read: scte tc scrf idle or nf fe pe write: reset:11000000 sci status register 2 (scs2) read: 000000bkfrpf write: reset:00000000 sci data register (scdr) read: r7 r6 r5 r4 r3 r2 r1 r0 write: t7 t6 t5 t4 t3 t2 t1 t0 reset: unaffected by reset sci baud rate register (scbr) read: 0 0 scp1 scp0 r scr2 scr1 scr0 write: reset:00000000 = unimplemented u = unaffected r = reserved figure 15-7. sci i/o receiver register summary table 15-4. sci receiver i/o address summary register scc1 scc2 scc3 scs1 scs2 scdr scbr address $0013 $0014 $0015 $0016 $0017 $0018 $0019 serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 200 serial communications interface (sci) motorola 15.5.3.1 character length the receiver can accommodate either 8-bit or 9-bit data. the state of the m bit in sci control register 1 (scc1) determines character length. when receiving 9-bit data, bit r8 in sci control register 2 (scc2) is the ninth bit (bit 8). when receiving 8-bit data, bit r8 is a copy of the eighth bit (bit 7). 15.5.3.2 character reception during an sci reception, the receive shift register shifts characters in from the rxd pin. the sci data register (scdr) is the read-only buffer between the internal data bus and the receive shift register. after a complete character shifts into the receive shift register, the data portion of the character transfers to the scdr. the sci receiver full bit, scrf, in sci status register 1 (scs1) becomes set, indicating that the received byte can be read. if the sci receive interrupt enable bit, scrie, in scc2 is also set, the scrf bit generates a receiver cpu interrupt request. 15.5.3.3 data sampling the receiver samples the rxd pin at the rt clock rate. the rt clock is an internal signal with a frequency 16 times the baud rate. to adjust for baud rate mismatch, the rt clock is resynchronized at the following times (see figure 15-8 ): after every start bit after the receiver detects a data bit change from logic 1 to logic 0 (after the majority of data bit samples at rt8, rt9, and rt10 returns a valid logic 1 and the majority of the next rt8, rt9, and rt10 samples returns a valid logic 0) to locate the start bit, data recovery logic does an asynchronous search for a logic 0 preceded by three logic 1s. when the falling edge of a possible start bit occurs, the rt clock begins to count to 16. serial communications interface (sci) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 201 figure 15-8. receiver data sampling to verify the start bit and to detect noise, data recovery logic takes samples at rt3, rt5, and rt7. table 15-5 summarizes the results of the start bit verification samples. if start bit verification is not successful, the rt clock is reset and a new search for a start bit begins. table 15-5. start bit verification rt3, rt5, and rt7 samples start bit verification noise flag 000 yes 0 001 yes 1 010 yes 1 011 no 0 100 yes 1 101 no 0 110 no 0 111 no 0 rt clock reset rt1 rt1 rt1 rt1 rt1 rt1 rt1 rt1 rt1 rt2 rt3 rt4 rt5 rt8 rt7 rt6 rt11 rt10 rt9 rt15 rt14 rt13 rt12 rt16 rt1 rt2 rt3 rt4 start bit qualification start bit verification data sampling samples rt clock rt clock state start bit lsb rxd serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 202 serial communications interface (sci) motorola to determine the value of a data bit and to detect noise, recovery logic takes samples at rt8, rt9, and rt10. table 15-6 summarizes the results of the data bit samples. note: the rt8, rt9, and rt10 samples do not affect start bit verification. if any or all of the rt8, rt9, and rt10 start bit samples are logic 1s following a successful start bit verification, the noise flag (nf) is set and the receiver assumes that the bit is a start bit. to verify a stop bit and to detect noise, recovery logic takes samples at rt8, rt9, and rt10. table 15-7 summarizes the results of the stop bit samples. table 15-6. data bit recovery rt8, rt9, and rt10 samples data bit determination noise flag 000 0 0 001 0 1 010 0 1 011 1 1 100 0 1 101 1 1 110 1 1 111 1 0 table 15-7. stop bit recovery rt8, rt9, and rt10 samples framing error flag noise flag 000 1 0 001 1 1 010 1 1 011 0 1 100 1 1 101 0 1 110 0 1 111 0 0 serial communications interface (sci) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 203 15.5.3.4 framing errors if the data recovery logic does not detect a logic 1 where the stop bit should be in an incoming character, it sets the framing error bit, fe, in scs1. a break character also sets the fe bit because a break character has no stop bit. the fe bit is set at the same time that the scrf bit is set. 15.5.3.5 baud rate tolerance a transmitting device may be operating at a baud rate below or above the receiver baud rate. accumulated bit time misalignment can cause one of the three stop bit data samples to fall outside the actual stop bit. then a noise error occurs. if more than one of the samples is outside the stop bit, a framing error occurs. in most applications, the baud rate tolerance is much more than the degree of misalignment that is likely to occur. as the receiver samples an incoming character, it resynchronizes the rt clock on any valid falling edge within the character. resynchronization within characters corrects misalignments between transmitter bit times and receiver bit times. slow data tolerance figure 15-9 shows how much a slow received character can be misaligned without causing a noise error or a framing error. the slow stop bit begins at rt8 instead of rt1 but arrives in time for the stop bit data samples at rt8, rt9, and rt10. figure 15-9. slow data msb stop rt1 rt2 rt3 rt4 rt5 rt6 rt7 rt8 rt9 rt10 rt11 rt12 rt13 rt14 rt15 rt16 data samples receiver rt clock serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 204 serial communications interface (sci) motorola for an 8-bit character, data sampling of the stop bit takes the receiver 9bit times 16 rt cycles + 10 rt cycles = 154 rt cycles. with the misaligned character shown in figure 15-9 , the receiver counts 154 rt cycles at the point when the count of the transmitting device is 9 bit times 16 rt cycles + 3 rt cycles = 147 rt cycles. the maximum percent difference between the receiver count and the transmitter count of a slow 8-bit character with no errors is for a 9-bit character, data sampling of the stop bit takes the receiver 10 bit times 16 rt cycles + 10 rt cycles = 170 rt cycles. with the misaligned character shown in figure 15-9 , the receiver counts 170 rt cycles at the point when the count of the transmitting device is 10 bit times 16 rt cycles + 3 rt cycles = 163 rt cycles. the maximum percent difference between the receiver count and the transmitter count of a slow 9-bit character with no errors is fast data tolerance figure 15-10 shows how much a fast received character can be misaligned without causing a noise error or a framing error. the fast stop bit ends at rt10 instead of rt16 but is still there for the stop bit data samples at rt8, rt9, and rt10. figure 15-10. fast data 154 147 ? 154 ------------------------- - 100 4.54% = 170 163 ? 170 ------------------------- - 100 4.12% = idle or next character stop rt1 rt2 rt3 rt4 rt5 rt6 rt7 rt8 rt9 rt10 rt11 rt12 rt13 rt14 rt15 rt16 data samples receiver rt clock serial communications interface (sci) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 205 for an 8-bit character, data sampling of the stop bit takes the receiver 9bittimes 16 rt cycles + 10 rt cycles = 154 rt cycles. with the misaligned character shown in figure 15-10 , the receiver counts 154 rt cycles at the point when the count of the transmitting device is 10 bit times 16 rt cycles = 160 rt cycles. the maximum percent difference between the receiver count and the transmitter count of a fast 8-bit character with no errors is for a 9-bit character, data sampling of the stop bit takes the receiver 10 bit times 16 rt cycles + 10 rt cycles = 170 rt cycles. with the misaligned character shown in figure 15-10 , the receiver counts 170 rt cycles at the point when the count of the transmitting device is 11 bit times 16 rt cycles = 176 rt cycles. the maximum percent difference between the receiver count and the transmitter count of a fast 9-bit character with no errors is 15.5.3.6 receiver wakeup so that the mcu can ignore transmissions intended only for other receivers in multiple-receiver systems, the receiver can be put into a standby state. setting the receiver wakeup bit, rwu, in scc2 puts the receiver into a standby state during which receiver interrupts are disabled. depending on the state of the wake bit in scc1, either of two conditions on the rxd pin can bring the receiver out of the standby state: address mark ? an address mark is a logic 1 in the most significant bit position of a received character. when the wake bit is set, an address mark wakes the receiver from the standby state by clearing the rwu bit. the address mark also sets the sci receiver full bit, scrf. software can then compare the character containing the address mark to the user-defined address of the receiver. if they are the same, the receiver remains awake and 154 160 ? 154 ------------------------- - 100 3.90%. = 170 176 ? 170 ------------------------- - 100 3.53%. = serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 206 serial communications interface (sci) motorola processes the characters that follow. if they are not the same, software can set the rwu bit and put the receiver back into the standby state. idle input line condition ? when the wake bit is clear, an idle character on the rxd pin wakes the receiver from the standby state by clearing the rwu bit. the idle character that wakes the receiver does not set the receiver idle bit, idle, or the sci receiver full bit, scrf. the idle line type bit, ilty, determines whether the receiver begins counting logic 1s as idle character bits after the start bit or after the stop bit. note: with the wake bit clear, setting the rwu bit after the rxd pin has been idle may cause the receiver to wake up immediately. 15.5.3.7 receiver interrupts the following sources can generate cpu interrupt requests from the sci receiver: sci receiver full (scrf) ? the scrf bit in scs1 indicates that the receive shift register has transferred a character to the scdr. scrf can generate a receiver cpu interrupt request. setting the sci receive interrupt enable bit, scrie, in scc2 enables the scrf bit to generate receiver cpu interrupts. idle input (idle) ? the idle bit in scs1 indicates that 10 or 11 consecutive logic 1s shifted in from the rxd pin. the idle line interrupt enable bit, ilie, in scc2 enables the idle bit to generate cpu interrupt requests. 15.5.3.8 error interrupts the following receiver error flags in scs1 can generate cpu interrupt requests: receiver overrun (or) ? the or bit indicates that the receive shift register shifted in a new character before the previous character was read from the scdr. the previous character serial communications interface (sci) low-power modes MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 207 remains in the scdr, and the new character is lost. the overrun interrupt enable bit, orie, in scc3 enables or to generate sci error cpu interrupt requests. noise flag (nf) ? the nf bit is set when the sci detects noise on incoming data or break characters, including start, data, and stop bits. the noise error interrupt enable bit, neie, in scc3 enables nf to generate sci error cpu interrupt requests. framing error (fe) ? the fe bit in scs1 is set when a logic 0 occurs where the receiver expects a stop bit. the framing error interrupt enable bit, feie, in scc3 enables fe to generate sci error cpu interrupt requests. parity error (pe) ? the pe bit in scs1 is set when the sci detects a parity error in incoming data. the parity error interrupt enable bit, peie, in scc3 enables pe to generate sci error cpu interrupt requests. 15.6 low-power modes the wait and stop instructions put the mcu in low power- consumption standby modes. 15.6.1 wait mode the sci module remains active in wait mode. any enabled cpu interrupt request from the sci module can bring the mcu out of wait mode. if sci module functions are not required during wait mode, reduce power consumption by disabling the module before executing the wait instruction. serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 208 serial communications interface (sci) motorola 15.6.2 stop mode the sci module is inactive in stop mode. the stop instruction does not affect sci register states. any enabled cpu interrupt request from the sci module does not bring the mcu out of stop mode. sci module operation resumes after the mcu exits stop mode. because the internal clock is inactive during stop mode, entering stop mode during an sci transmission or reception results in invalid data. 15.7 sci during break module interrupts the bcfe bit in the break flag control register (bfcr) enables software to clear status bits during the break state. (see break module on page 149). to allow software to clear status bits during a break interrupt, write a logic 1 to the bcfe bit. if a status bit is cleared during the break state, it remains cleared when the mcu exits the break state. to protect status bits during the break state, write a logic 0 to the bcfe bit. with bcfe at logic 0 (its default state), software can read and write i/o registers during the break state without affecting status bits. some status bits have a two-step read/write clearing procedure. if software does the first step on such a bit before the break, the bit cannot change during the break state as long as bcfe is at logic 0. after the break, doing the second step clears the status bit. 15.8 i/o signals port e shares two of its pins with the sci module. the two sci i/o pins are: pte0/txd ? transmit data pte1/rxd ? receive data serial communications interface (sci) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 209 15.8.1 pte0/txd (transmit data) the pte0/txd pin is the serial data output from the sci transmitter. the sci shares the pte0/txd pin with port e. when the sci is enabled, the pte0/txd pin is an output regardless of the state of the ddre2 bit in data direction register e (ddre). 15.8.2 pte1/rxd (receive data) the pte1/rxd pin is the serial data input to the sci receiver. the sci shares the pte1/rxd pin with port e. when the sci is enabled, the pte1/rxd pin is an input regardless of the state of the ddre1 bit in data direction register e (ddre). 15.9 i/o registers the following i/o registers control and monitor sci operation: sci control register 1 (scc1) sci control register 2 (scc2) sci control register 3 (scc3) sci status register 1 (scs1) sci status register 2 (scs2) sci data register (scdr) sci baud rate register (scbr) 15.9.1 sci control register 1 sci control register 1: enables loop mode operation enables the sci controls output polarity controls character length controls sci wakeup method serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 210 serial communications interface (sci) motorola controls idle character detection enables parity function controls parity type loops ? loop mode select bit this read/write bit enables loop mode operation. in loop mode the rxd pin is disconnected from the sci, and the transmitter output goes into the receiver input. both the transmitter and the receiver must be enabled to use loop mode. reset clears the loops bit. 1 = loop mode enabled 0 = normal operation enabled ensci ? enable sci bit this read/write bit enables the sci and the sci baud rate generator. clearing ensci sets the scte and tc bits in sci status register 1 and disables transmitter interrupts. reset clears the ensci bit. 1 = sci enabled 0 = sci disabled txinv ? transmit inversion bit this read/write bit reverses the polarity of transmitted data. reset clears the txinv bit. 1 = transmitter output inverted 0 = transmitter output not inverted note: setting the txinv bit inverts all transmitted values, including idle, break, start, and stop bits. address: $0013 bit 7654321bit 0 read: loops ensci txinv m wake illty pen pty write: reset:00000000 figure 15-11. sci control register 1 (scc1) serial communications interface (sci) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 211 m ? mode (character length) bit this read/write bit determines whether sci characters are eight or nine bits long. (see table 15-8 ).the ninth bit can serve as an extra stop bit, as a receiver wakeup signal, or as a parity bit. reset clears the m bit. 1 = 9-bit sci characters 0 = 8-bit sci characters wake ? wakeup condition bit this read/write bit determines which condition wakes up the sci: a logic 1 (address mark) in the most significant bit position of a received character or an idle condition on the rxd pin. reset clears the wake bit. 1 = address mark wakeup 0 = idle line wakeup ilty ? idle line type bit this read/write bit determines when the sci starts counting logic 1s as idle character bits. the counting begins either after the start bit or after the stop bit. if the count begins after the start bit, then a string of logic 1s preceding the stop bit may cause false recognition of an idle character. beginning the count after the stop bit avoids false idle character recognition, but requires properly synchronized transmissions. reset clears the ilty bit. 1 = idle character bit count begins after stop bit 0 = idle character bit count begins after start bit pen ? parity enable bit this read/write bit enables the sci parity function. (see table 15-8 ). when enabled, the parity function inserts a parity bit in the most significant bit position. (see table 15-7 ). reset clears the pen bit. 1 = parity function enabled 0 = parity function disabled serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 212 serial communications interface (sci) motorola pty ? parity bit this read/write bit determines whether the sci generates and checks for odd parity or even parity. (see table 15-8 ). reset clears the pty bit. 1 = odd parity 0 = even parity note: changing the pty bit in the middle of a transmission or reception can generate a parity error. 15.9.2 sci control register 2 sci control register 2: enables the following cpu interrupt requests: ? enables the scte bit to generate transmitter cpu interrupt requests ? enables the tc bit to generate transmitter cpu interrupt requests ? enables the scrf bit to generate receiver cpu interrupt requests ? enables the idle bit to generate receiver cpu interrupt requests table 15-8. character format selection control bits character format mpen:pty start bits data bits parity stop bits character length 0 0x 1 8 none 1 10 bits 1 0x 1 9 none 1 11 bits 0 10 1 7 even 1 10 bits 011 17odd110 bits 1 10 1 8 even 1 11 bits 111 18odd111 bits serial communications interface (sci) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 213 enables the transmitter enables the receiver enables sci wakeup transmits sci break characters sctie ? sci transmit interrupt enable bit this read/write bit enables the scte bit to generate sci transmitter cpu interrupt requests. setting the sctie bit in scc3 enables the scte bit to generate cpu interrupt requests. reset clears the sctie bit. 1 = scte enabled to generate cpu interrupt 0 = scte not enabled to generate cpu interrupt tcie ? transmission complete interrupt enable bit this read/write bit enables the tc bit to generate sci transmitter cpu interrupt requests. reset clears the tcie bit. 1 = tc enabled to generate cpu interrupt requests 0 = tc not enabled to generate cpu interrupt requests scrie ? sci receive interrupt enable bit this read/write bit enables the scrf bit to generate sci receiver cpu interrupt requests. setting the scrie bit in scc3 enables the scrf bit to generate cpu interrupt requests. reset clears the scrie bit. 1 = scrf enabled to generate cpu interrupt 0 = scrf not enabled to generate cpu interrupt address: $0014 bit 7654321bit 0 read: sctie tcie scrie ilie te re rwu sbk write: reset:00000000 figure 15-12. sci control register 2 (scc2) serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 214 serial communications interface (sci) motorola ilie ? idle line interrupt enable bit this read/write bit enables the idle bit to generate sci receiver cpu interrupt requests. reset clears the ilie bit. 1 = idle enabled to generate cpu interrupt requests 0 = idle not enabled to generate cpu interrupt requests te ? transmitter enable bit setting this read/write bit begins the transmission by sending a preamble of 10 or 11 logic 1s from the transmit shift register to the txd pin. if software clears the te bit, the transmitter completes any transmission in progress before the txd returns to the idle condition (logic 1). clearing and then setting te during a transmission queues an idle character to be sent after the character currently being transmitted. reset clears the te bit. 1 = transmitter enabled 0 = transmitter disabled note: writing to the te bit is not allowed when the enable sci bit (ensci) is clear. ensci is in sci control register 1. re ? receiver enable bit setting this read/write bit enables the receiver. clearing the re bit disables the receiver but does not affect receiver interrupt flag bits. reset clears the re bit. 1 = receiver enabled 0 = receiver disabled note: writing to the re bit is not allowed when the enable sci bit (ensci) is clear. ensci is in sci control register 1. rwu ? receiver wakeup bit this read/write bit puts the receiver in a standby state during which receiver interrupts are disabled. the wake bit in scc1 determines whether an idle input or an address mark brings the receiver out of the standby state and clears the rwu bit. reset clears the rwu bit. 1 = standby state 0 = normal operation serial communications interface (sci) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 215 sbk ? send break bit setting and then clearing this read/write bit transmits a break character followed by a logic 1. the logic 1 after the break character guarantees recognition of a valid start bit. if sbk remains set, the transmitter continuously transmits break characters with no logic 1s between them. reset clears the sbk bit. 1 = transmit break characters 0 = no break characters being transmitted note: do not toggle the sbk bit immediately after setting the scte bit. toggling sbk before the preamble begins causes the sci to send a break character instead of a preamble. 15.9.3 sci control register 3 sci control register 3: stores the ninth sci data bit received and the ninth sci data bit to be transmitted. enables the following interrupts: ? receiver overrun interrupts ? noise error interrupts ? framing error interrupts ? parity error interrupts address: $0015 bit 7654321bit 0 read: r8 t8 r r orie neie feie peie write: reset:uu000000 = unimplemented r = reserved u = unaffected figure 15-13. sci control register 3 (scc3) serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 216 serial communications interface (sci) motorola r8 ? received bit 8 when the sci is receiving 9-bit characters, r8 is the read-only ninth bit (bit 8) of the received character. r8 is received at the same time that the scdr receives the other 8 bits. when the sci is receiving 8-bit characters, r8 is a copy of the eighth bit (bit 7). reset has no effect on the r8 bit. t8 ? transmitted bit 8 when the sci is transmitting 9-bit characters, t8 is the read/write ninth bit (bit 8) of the transmitted character. t8 is loaded into the transmit shift register at the same time that the scdr is loaded into the transmit shift register. reset has no effect on the t8 bit. orie ? receiver overrun interrupt enable bit this read/write bit enables sci error cpu interrupt requests generated by the receiver overrun bit, or. 1 = sci error cpu interrupt requests from or bit enabled 0 = sci error cpu interrupt requests from or bit disabled neie ? receiver noise error interrupt enable bit this read/write bit enables sci error cpu interrupt requests generated by the noise error bit, ne. reset clears neie. 1 = sci error cpu interrupt requests from ne bit enabled 0 = sci error cpu interrupt requests from ne bit disabled feie ? receiver framing error interrupt enable bit this read/write bit enables sci error cpu interrupt requests generated by the framing error bit, fe. reset clears feie. 1 = sci error cpu interrupt requests from fe bit enabled 0 = sci error cpu interrupt requests from fe bit disabled peie ? receiver parity error interrupt enable bit this read/write bit enables sci receiver cpu interrupt requests generated by the parity error bit, pe. reset clears peie. 1 = sci error cpu interrupt requests from pe bit enabled 0 = sci error cpu interrupt requests from pe bit disabled serial communications interface (sci) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 217 15.9.4 sci status register 1 sci status register 1 contains flags to signal the following conditions: transfer of scdr data to transmit shift register complete transmission complete transfer of receive shift register data to scdr complete receiver input idle receiver overrun noisy data framing error parity error scte ? sci transmitter empty bit this clearable, read-only bit is set when the scdr transfers a character to the transmit shift register. scte can generate an sci transmitter cpu interrupt request. when the sctie bit in scc2 is set, scte generates an sci transmitter cpu interrupt request. in normal operation, clear the scte bit by reading scs1 with scte set and then writing to scdr. reset sets the scte bit. 1 = scdr data transferred to transmit shift register 0 = scdr data not transferred to transmit shift register address: $0016 bit 7654321bit 0 read: scte tc scrf idle or nf fe pe write: reset:11000000 = unimplemented figure 15-14. sci status register 1 (scs1) serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 218 serial communications interface (sci) motorola tc ? transmission complete bit this read-only bit is set when the scte bit is set, and no data, preamble, or break character is being transmitted. tc generates an sci transmitter cpu interrupt request if the tcie bit in scc2 is also set. tc is cleared automatically when data, preamble, or break is queued and ready to be sent. there may be up to 1.5 transmitter clocks of latency between queueing data, preamble, and break and the transmission actually starting. reset sets the tc bit. 1 = no transmission in progress 0 = transmission in progress scrf ? sci receiver full bit this clearable, read-only bit is set when the data in the receive shift register transfers to the sci data register. scrf can generate an sci receiver cpu interrupt request. when the scrie bit in scc2 is set the scrf generates a cpu interrupt request. in normal operation, clear the scrf bit by reading scs1 with scrf set and then reading the scdr. reset clears scrf. 1 = received data available in scdr 0 = data not available in scdr idle ? receiver idle bit this clearable, read-only bit is set when 10 or 11 consecutive logic 1s appear on the receiver input. idle generates an sci error cpu interrupt request if the ilie bit in scc2 is also set. clear the idle bit by reading scs1 with idle set and then reading the scdr. after the receiver is enabled, it must receive a valid character that sets the scrf bit before an idle condition can set the idle bit. also, after the idle bit has been cleared, a valid character must again set the scrf bit before an idle condition can set the idle bit. reset clears the idle bit. 1 = receiver input idle 0 = receiver input active (or idle since the idle bit was cleared) or ? receiver overrun bit this clearable, read-only bit is set when software fails to read the scdr before the receive shift register receives the next character. the or bit generates an sci error cpu interrupt request if the orie serial communications interface (sci) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 219 bit in scc3 is also set. the data in the shift register is lost, but the data already in the scdr is not affected. clear the or bit by reading scs1 with or set and then reading the scdr. reset clears the or bit. 1 = receive shift register full and scrf = 1 0 = no receiver overrun software latency may allow an overrun to occur between reads of scs1 and scdr in the flag-clearing sequence. figure 15-15 shows the normal flag-clearing sequence and an example of an overrun caused by a delayed flag-clearing sequence. the delayed read of scdr does not clear the or bit because or was not set when scs1 was read. byte 2 caused the overrun and is lost. the next flag-clearing sequence reads byte 3 in the scdr instead of byte 2. in applications that are subject to software latency or in which it is important to know which byte is lost due to an overrun, the flag-clearing routine can check the or bit in a second read of scs1 after reading the data register. figure 15-15. flag clearing sequence byte 1 normal flag clearing sequence read scs1 scrf = 1 read scdr byte 1 scrf = 1 scrf = 1 byte 2 byte 3 byte 4 or = 0 read scs1 scrf = 1 or = 0 read scdr byte 2 scrf = 0 read scs1 scrf = 1 or = 0 scrf = 1 scrf = 0 read scdr byte 3 scrf = 0 byte 1 read scs1 scrf = 1 read scdr byte 1 scrf = 1 scrf = 1 byte 2 byte 3 byte 4 or = 0 read scs1 scrf = 1 or = 1 read scdr byte 3 delayed flag clearing sequence or = 1 scrf = 1 or = 1 scrf = 0 or = 1 scrf = 0 or = 0 serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 220 serial communications interface (sci) motorola nf ? receiver noise flag bit this clearable, read-only bit is set when the sci detects noise on the rxd pin. nf generates an nf cpu interrupt request if the neie bit in scc3 is also set. clear the nf bit by reading scs1 and then reading the scdr. reset clears the nf bit. 1 = noise detected 0 = no noise detected fe ? receiver framing error bit this clearable, read-only bit is set when a logic 0 is accepted as the stop bit. fe generates an sci error cpu interrupt request if the feie bit in scc3 also is set. clear the fe bit by reading scs1 with fe set and then reading the scdr. reset clears the fe bit. 1 = framing error detected 0 = no framing error detected pe ? receiver parity error bit this clearable, read-only bit is set when the sci detects a parity error in incoming data. pe generates a pe cpu interrupt request if the peie bit in scc3 is also set. clear the pe bit by reading scs1 with pe set and then reading the scdr. reset clears the pe bit. 1 = parity error detected 0 = no parity error detected serial communications interface (sci) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 221 15.9.5 sci status register 2 sci status register 2 contains flags to signal the following conditions: break character detected incoming data bkf ? break flag bit this clearable, read-only bit is set when the sci detects a break character on the rxd pin. in scs1, the fe and scrf bits are also set. in 9-bit character transmissions, the r8 bit in scc3 is cleared. bkf does not generate a cpu interrupt request. clear bkf by reading scs2 with bkf set and then reading the scdr. once cleared, bkf can become set again only after logic 1s again appear on the rxd pin followed by another break character. reset clears the bkf bit. 1 = break character detected 0 = no break character detected address: $0017 bit 7654321bit 0 read: 000000bkfrpf write: reset:00000000 = unimplemented figure 15-16. sci status register 2 (scs2) serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 222 serial communications interface (sci) motorola rpf ? reception in progress flag bit this read-only bit is set when the receiver detects a logic 0 during the rt1 time period of the start bit search. rpf does not generate an interrupt request. rpf is reset after the receiver detects false start bits (usually from noise or a baud rate mismatch), or when the receiver detects an idle character. polling rpf before disabling the sci module or entering stop mode can show whether a reception is in progress. 1 = reception in progress 0 = no reception in progress 15.9.6 sci data register the sci data register is the buffer between the internal data bus and the receive and transmit shift registers. reset has no effect on data in the sci data register. r7/t7:r0/t0 ? receive/transmit data bits reading address $0018 accesses the read-only received data bits, r7:r0. writing to address $0018 writes the data to be transmitted, t7:t0. reset has no effect on the sci data register. note: do not use read-modify-write instructions on the sci data register. address: $0018 bit 7654321bit 0 read: r7 r6 r5 r4 r3 r2 r1 r0 write: t7 t6 t5 t4 t3 t2 t1 t0 reset: unaffected by reset figure 15-17. sci data register (scdr) serial communications interface (sci) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 223 15.9.7 sci baud rate register the baud rate register selects the baud rate for both the receiver and the transmitter. scp1 and scp0 ? sci baud rate prescaler bits these read/write bits select the baud rate prescaler divisor as shown in table 15-9 . reset clears scp1 and scp0. address: $0019 bit 7654321bit 0 read: 0 0 scp1 scp0 r scr2 scr1 scr0 write: reset:00000000 = unimplemented r = reserved figure 15-18. sci baud rate register (scbr) table 15-9. sci baud rate prescaling scp[1:0] prescaler divisor (pd) 00 1 01 3 10 4 11 13 serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 224 serial communications interface (sci) motorola scr2 ? scr0 ? sci baud rate select bits these read/write bits select the sci baud rate divisor as shown in table 15-10 . reset clears scr2 ? scr0. use the following formula to calculate the sci baud rate: where: f crystal = crystal frequency pd = prescaler divisor bd = baud rate divisor table 15-11 shows the sci baud rates that can be generated with a 4.9152-mhz crystal. table 15-10. sci baud rate selection scr[2:1:0] baud rate divisor (bd) 000 1 001 2 010 4 011 8 100 16 101 32 110 64 111 128 baud rate f crystal 64 pd bd ------------------------------------ = serial communications interface (sci) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial communications interface (sci) 225 table 15-11. sci baud rate selection examples scp[1:0] prescaler divisor (pd) scr[2:1:0] baud rate divisor (bd) baud rate (f crystal = 4.9152 mhz) 00 1 000 1 76,800 00 1 001 2 38,400 00 1 010 4 19,200 00 1 011 8 9600 00 1 100 16 4800 00 1 101 32 2400 00 1 110 64 1200 00 1 111 128 600 01 3 000 1 25,600 01 3 001 2 12,800 01 3 010 4 6400 01 3 011 8 3200 01 3 100 16 1600 01 3 101 32 800 01 3 110 64 400 01 3 111 128 200 10 4 000 1 19,200 10 4 001 2 9600 10 4 010 4 4800 10 4 011 8 2400 10 4 100 16 1200 10 4 101 32 600 10 4 110 64 300 10 4 111 128 150 11 13 000 1 5908 11 13 001 2 2954 11 13 010 4 1477 11 13 011 8 739 11 13 100 16 369 11 13 101 32 185 11 13 110 64 92 11 13 111 128 46 serial communications interface (sci) technical data MC68HC08AZ32A ? rev 1.0 226 serial communications interface (sci) motorola MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 227 technical data ? MC68HC08AZ32A section 16. serial peripheral interface (spi) 16.1 contents 16.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228 16.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228 16.4 pin name conventions and i/o register addresses . . . . . 229 16.5 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230 16.5.1 master mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 16.5.2 slave mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233 16.6 transmission formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234 16.6.1 clock phase and polarity controls . . . . . . . . . . . . . . . . . 234 16.6.2 transmission format when cpha = ? 0 ? . . . . . . . . . . . . . 235 16.6.3 transmission format when cpha = ? 1 ? . . . . . . . . . . . . . 236 16.6.4 transmission initiation latency . . . . . . . . . . . . . . . . . . . 237 16.6.5 error conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 16.6.6 overflow error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 16.6.7 mode fault error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241 16.7 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 16.8 queuing transmission data . . . . . . . . . . . . . . . . . . . . . . . . 244 16.9 resetting the spi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246 16.10 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247 16.10.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247 16.10.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247 16.11 spi during break interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 247 16.12 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248 16.12.1 miso (masterin/slave out) . . . . . . . . . . . . . . . . . . . . . . . 249 16.12.2 mosi (master out/slave in) . . . . . . . . . . . . . . . . . . . . . . . 249 serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 228 serial peripheral interface (spi) motorola 16.12.3 spsck (serial clock) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 16.12.4 ss (slave select) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 16.12.5 vss (clock ground) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 16.13 i/o registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 16.13.1 spi control register (spcr) . . . . . . . . . . . . . . . . . . . . . . 252 16.13.2 spi status and control register (spscr) . . . . . . . . . . . 254 16.13.3 spi data register (spdr) . . . . . . . . . . . . . . . . . . . . . . . . 258 16.2 introduction this section describes the serial peripheral interface module (spi), which allows full-duplex, synchronous, serial communications with peripheral devices. 16.3 features features of the spi module include the following: full-duplex operation master and slave modes double-buffered operation with separate transmit and receive registers four master mode frequencies (maximum = bus frequency 2) maximum slave mode frequency = bus frequency serial clock with programmable polarity and phase two separately enabled interrupts with cpu service: ? sprf (spi receiver full) ? spte (spi transmitter empty) mode fault error flag with cpu interrupt capability overflow error flag with cpu interrupt capability programmable wired-or mode i 2 c (inter-integrated circuit) compatibility serial peripheral interface (spi) pin name conventions and i/o register addresses MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 229 16.4 pin name conventions and i/o register addresses the generic names of the spi input/output (i/o) pins are: ss (slave select) spsck (spi serial clock) mosi (master out slave in) miso (master in slave out) the spi shares four i/o pins with a parallel i/o port. the full name of an spi pin reflects the name of the shared port pin. table 16-1 shows the full names of the spi i/o pins. the generic pin names appear in the text that follows.: the generic pins names appear in the text that follows. table 16-1. pin name conventions spi generic pin names: miso mosi ss sck v ss full spi pin names: spi pte5/miso pte6/mosi pte4/ss pte7/spsck cgnd table 16-2. i/o register addresses register name register address spi control register (spicr) $0010 spi status and control register (spiscr) $0011 spi data register (spidr) $0012 serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 230 serial peripheral interface (spi) motorola 16.5 functional description figure 16-1 summarizes the spi i/o registers and figure 16-2 show the structure of the spi module. register name r/w bit 7 6 5 4 3 2 1 bit 0 spi control register (spcr) read: sprie r spmstr cpol cpha spwom spe sptie write: reset:00 1 0 1 0 00 spi status and control register (spscr) read: sprf errie ovrf modf spte modfen spr1 spr0 write: reset:00 0 0 1 0 00 spi data register (spdr) read: r7 r6 r5 r4 r3 r2 r1 r0 write: t7 t6 t5 t4 t3 t2 t1 t0 reset: unaffected by reset r=reserved = unimplemented figure 16-1. spi i/o register summary serial peripheral interface (spi) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 231 figure 16-2. spi module block diagram the spi module allows full-duplex, synchronous, serial communication between the mcu and peripheral devices, including other mcus. software can poll the spi status flags or spi operation can be interrupt- driven. all spi interrupts can be serviced by the cpu. the following paragraphs describe the operation of the spi module. transmitter cpu interrupt request receiver/error cpu interrupt request 76543210 spr1 spmstr transmit data register shift register spr0 bus clock clock select 2 clock divider 8 32 128 clock logic cpha cpol spi sprie spe spwom sprf spte ovrf m s pin control logic receive data register sptie spe internal bus modfen errie control modf spmstr mosi miso spsck ss serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 232 serial peripheral interface (spi) motorola 16.5.1 master mode the spi operates in master mode when the spi master bit, spmstr, is set. note: configure the spi modules as master and slave before enabling them. enable the master spi before enabling the slave spi. disable the slave spi before disabling the master spi. see spi control register (spcr) on page 252. only a master spi module can initiate transmissions. software begins the transmission from a master spi module by writing to the spi data register. if the shift register is empty, the byte immediately transfers to the shift register, setting the spi transmitter empty bit, spte. the byte begins shifting out on the mosi pin under the control of the serial clock. see figure 16-3 . the spr1 and spr0 bits control the baud rate generator and determine the speed of the shift register. see spi status and control register (spscr) on page 254. through the spsck pin, the baud rate generator of the master also controls the shift register of the slave peripheral. as the byte shifts out on the mosi pin of the master, another byte shifts in from the slave on the master ? s miso pin. the transmission ends when the receiver full bit, sprf, becomes set. at the same time that sprf becomes set, the byte from the slave transfers to the receive data register. in normal operation, sprf signals the end of a transmission. software clears sprf by reading the spi status and control register with serial peripheral interface (spi) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 233 sprf set and then reading the spi data register. writing to the spi data register clears the sptie bit. 16.5.2 slave mode the spi operates in slave mode when the spmstr bit is clear. in slave mode the spsck pin is the input for the serial clock from the master mcu. before a data transmission occurs, the ss pin of the slave mcu must be at logic ? 0 ? . ss must remain low until the transmission is complete. see mode fault error on page 241. in a slave spi module, data enters the shift register under the control of the serial clock from the master spi module. after a byte enters the shift register of a slave spi, it transfers to the receive data register, and the sprf bit is set. to prevent an overflow condition, slave software must then read the spi data register before another byte enters the shift register. the maximum frequency of the spsck for an spi configured as a slave is the bus clock speed (which is twice as fast as the fastest master spsck clock that can be generated). the frequency of the spsck for an spi configured as a slave does not have to correspond to any particular spi baud rate. the baud rate only controls the speed of the spsck generated by an spi configured as a master. therefore, the figure 16-3. full-duplex master-slave connections shift register shift register baud rate generator master mcu slave mcu v dd mosi mosi miso miso spsck spsck ss ss serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 234 serial peripheral interface (spi) motorola frequency of the spsck for an spi configured as a slave can be any frequency less than or equal to the bus speed. when the master spi starts a transmission, the data in the slave shift register begins shifting out on the miso pin. the slave can load its shift register with a new byte for the next transmission by writing to its transmit data register. the slave must write to its transmit data register at least one bus cycle before the master starts the next transmission. otherwise the byte already in the slave shift register shifts out on the miso pin. data written to the slave shift register during a a transmission remains in a buffer until the end of the transmission. when the clock phase bit (cpha) is set, the first edge of spsck starts a transmission. when cpha is clear, the falling edge of ss starts a transmission. see transmission formats on page 234. if the write to the data register is late, the spi transmits the data already in the shift register from the previous transmission. note: spsck must be in the proper idle state before the slave is enabled to prevent spsck from appearing as a clock edge. 16.6 transmission formats during an spi transmission, data is simultaneously transmitted (shifted out serially) and received (shifted in serially). a serial clock line synchronizes shifting and sampling on the two serial data lines. a slave select line allows individual selection of a slave spi device; slave devices that are not selected do not interfere with spi bus activities. on a master spi device, the slave select line can optionally be used to indicate a multiple-master bus contention. 16.6.1 clock phase and polarity controls software can select any of four combinations of serial clock (sck) phase and polarity using two bits in the spi control register (spcr). the clock polarity is specified by the cpol control bit, which selects an active high or low clock and has no significant effect on the transmission format. serial peripheral interface (spi) transmission formats MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 235 the clock phase (cpha) control bit selects one of two fundamentally different transmission formats. the clock phase and polarity should be identical for the master spi device and the communicating slave device. in some cases, the phase and polarity are changed between transmissions to allow a master device to communicate with peripheral slaves having different requirements. note: before writing to the cpol bit or the cpha bit, the spi should be disabled by clearing the spi enable bit (spe). 16.6.2 transmission format when cpha = ? 0 ? figure 16-4 shows an spi transmission in which cpha is ? 0 ? . the figure should not be used as a replacement for data sheet parametric information.two waveforms are shown for sck: one for cpol = ? 0 ? and another for cpol = ? 1 ? . the diagram may be interpreted as a master or slave timing diagram since the serial clock (sck), master in/slave out (miso), and master out/slave in (mosi) pins are directly connected between the master and the slave. the miso signal is the output from the slave, and the mosi signal is the output from the master. the ss line is the slave select input to the slave. the slave spi drives its miso output only when its slave select input (ss ) is at logic ? 0 ? , so that only the selected slave drives to the master. the ss pin of the master is not shown but is assumed to be inactive. the ss pin of the master must be high or must be reconfigured as general purpose i/o not affecting the spi. see mode fault error on page 241. when cpha = ? 0 ? , the first spsck edge is the msb capture strobe. therefore the slave must begin driving its data before the first spsck edge, and a falling edge on the ss pin is used to start the transmission. the ss pin must be toggled high and then low again between each byte transmitted. serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 236 serial peripheral interface (spi) motorola figure 16-4. transmission format (cpha = ? 0 ? ) 16.6.3 transmission format when cpha = ? 1 ? figure 16-5 shows an spi transmission in which cpha is ? 1 ? . the figure should not be used as a replacement for data sheet parametric information. two waveforms are shown for sck: one for cpol = ? 0 ? and another for cpol = ? 1 ? . the diagram may be interpreted as a master or slave timing diagram since the serial clock (sck), master in/slave out (miso), and master out/slave in (mosi) pins are directly connected between the master and the slave. the miso signal is the output from the slave, and the mosi signal is the output from the master. the ss line is the slave select input to the slave. the slave spi drives its miso output only when its slave select input (ss ) is at logic ? 0 ? , so that only the selected slave drives to the master. the ss pin of the master is not shown but is assumed to be inactive. the ss pin of the master must be high or must be reconfigured as general-purpose i/o not affecting the spi. see mode fault error on page 241. when cpha = ? 1 ? , the master begins driving its mosi pin on the first spsck edge. therefore the slave uses the first spsck edge as a start transmission signal. the ss pin can remain low between transmissions. this format may be preferable in bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 lsb msb bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 lsb msb 1234 5678 sck cycle # (for reference) sck (cpol = ? 0 ? ) sck (cpol =1) mosi (from master) miso (from slave) ss (to slave) capture strobe serial peripheral interface (spi) transmission formats MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 237 systems having only one master and only one slave driving the miso data line. figure 16-5. transmission format (cpha = ? 1 ? ) 16.6.4 transmission initiation latency when the spi is configured as a master (spmstr = ? 1 ? ), transmissions are started by a software write to the spdr. cpha has no effect on the delay to the start of the transmission, but it does affect the initial state of the sck signal. when cpha = ? 0 ? , the sck signal remains inactive for the first half of the first sck cycle. when cpha = ? 1 ? , the first sck cycle begins with an edge on the sck line from its inactive to its active level. the spi clock rate (selected by spr1:spr0) affects the delay from the write to spdr and the start of the spi transmission. see figure 16-6 . the internal spi clock in the master is a free-running derivative of the internal mcu clock. it is only enabled when both the spe and spmstr bits are set to conserve power. sck edges occur halfway through the low time of the internal mcu clock. since the spi clock is free-running, it is uncertain where the write to the spdr will occur relative to the slower sck. this uncertainty causes the variation in the initiation delay shown in figure 16-6 . this delay will be no longer than a single spi bit time. that is, the maximum delay is two mcu bus cycles for div2, eight mcu bus cycles for div8, 32 mcu bus cycles for div32, and 128 mcu bus cycles for div128. bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 lsb msb bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 lsb msb 1234 5678 sck cycle # (for reference) sck (cpol = ? 0 ? ) sck (cpol =1) mosi (from master) miso (from slave) ss (to slave) capture strobe serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 238 serial peripheral interface (spi) motorola figure 16-6. transmission start delay (master) write to spdr initiation delay bus mosi sck (cpha = ? 1 ? ) sck (cpha = ? 0 ? ) sck cycle number msb bit 6 12 clock write to spdr earliest latest (sck = internal clock 2; earliest latest 2 possible start points) (sck = internal clock 8; 8 possible start points) earliest latest (sck = internal clock 32; 32 possible start points) earliest latest (sck = internal clock 128; 128 possible start points) write to spdr write to spdr write to spdr bus clock bit 5 3 bus clock bus clock bus clock ? ? ? initiation delay from write spdr to transfer begin serial peripheral interface (spi) transmission formats MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 239 16.6.5 error conditions the following flags signal spi error conditions: overflow (ovrf) ? failing to read the spi data register before the next byte enters the shift register results in the ovrf bit becoming set. the new byte does not transfer to the receive data register, and the unread byte still can be read by accessing the spi data register. ovrf is in the spi status and control register. mode fault error (modf) ? the modf bit indicates that the voltage on the slave select pin (ss ) is inconsistent with the mode of the spi. modf is in the spi status and control register. 16.6.6 overflow error the overflow flag (ovrf) becomes set if the spi receive data register still has unread data from a previous transmission when the capture strobe of bit 1 of the next transmission occurs. see figure 16-4 and figure 16-5 . if an overflow occurs, the data being received is not transferred to the receive data register so that the unread data can still be read. therefore, an overflow error always indicates the loss of data. ovrf generates a receiver/error cpu interrupt request if the error interrupt enable bit (errie) is also set. modf and ovrf can generate a receiver/error cpu interrupt request. see figure 16-9 . it is not possible to enable only modf or ovrf to generate a receiver/error cpu interrupt request. however, leaving modfen low prevents modf from being set. if an end-of-block transmission interrupt was meant to pull the mcu out of wait, having an overflow condition without overflow interrupts enabled causes the mcu to hang in wait mode. if the ovrf is enabled to generate an interrupt, it can pull the mcu out of wait mode instead. if the cpu sprf interrupt is enabled and the ovrf interrupt is not, watch for an overflow condition. figure 16-7 shows how it is possible to miss an overflow. serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 240 serial peripheral interface (spi) motorola figure 16-7. missed read of overflow condition the first part of figure 16-7 shows how to read the spscr and spdr to clear the sprf without problems. however, as illustrated by the second transmission example, the ovrf flag can be set in the interval between spscr and spdr being read. in this case, an overflow can easily be missed. since no more sprf interrupts can be generated until this ovrf is serviced, it will not be obvious that bytes are being lost as more transmissions are completed. to prevent this, the ovrf interrupt should be enabled, or alternatively another read of the spscr should be carried out following the read of the spdr. this ensures that the ovrf was not set before the sprf was cleared and that future transmissions will terminate with an sprf interrupt. figure 16-8 illustrates this process. generally, to avoid this second spscr read, enable the ovrf to the cpu by setting the errie bit. read spdr read spscr ovrf sprf byte 1 byte 2 byte 3 byte 4 byte 1 sets sprf bit. cpu reads spscr with sprf bit set cpu reads byte 1 in spdr, byte 2 sets sprf bit. cpu reads spscrw with sprf bit set byte 3 sets ovrf bit. byte 3 is lost. cpu reads byte 2 in spdr, clearing sprf byte 4 fails to set sprf bit because 1 1 2 3 4 5 6 7 8 2 3 4 5 6 7 8 clearing sprf bit. but not ovrf bit. ovrf bit is set. byte 4 is lost. and ovrf bit clear. and ovrf bit clear. serial peripheral interface (spi) transmission formats MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 241 figure 16-8. clearing sprf when ovrf interrupt is not enabled 16.6.7 mode fault error for the modf flag to be set, the mode fault error enable bit (modfen) must be set. clearing the modfen bit does not clear the modf flag but does prevent modf from being set again after modf is cleared. modf generates a receiver/error cpu interrupt request if the error interrupt enable bit (errie) is also set. the sprf, modf, and ovrf interrupts share the same cpu interrupt vector. modf and ovrf can generate a receiver/error cpu interrupt request. see figure 16-9 . it is not possible to enable only modf or ovrf to generate a receiver/error cpu interrupt request. however, leaving modfen low prevents modf from being set. read spdr read spscr ovrf sprf byte 1 byte 2 byte 3 byte 4 1 byte 1 sets sprf bit. cpu reads spscr with sprf bit set cpu reads byte 1 in spdr, cpu reads spscr again byte 2 sets sprf bit. cpu reads spscr with sprf bit set byte 3 sets ovrf bit. byte 3 is lost. cpu reads byte 2 in spdr, cpu reads spscr again cpu reads byte 2 spdr, byte 4 sets sprf bit. cpu reads spscr. cpu reads byte 4 in spdr, cpu reads spscr again 1 2 3 clearing sprf bit. 4 to check ovrf bit. 5 6 7 8 9 clearing sprf bit. to check ovrf bit. clearing ovrf bit. 2 3 4 5 6 7 8 9 10 11 12 13 14 clearing sprf bit. to check ovrf bit. spi receive complete and ovrf bit clear. and ovrf bit clear. 10 11 12 13 14 serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 242 serial peripheral interface (spi) motorola in a master spi with the mode fault enable bit (modfen) set, the mode fault flag (modf) is set if ss goes to logic ? 0 ? . a mode fault in a master spi causes the following events to occur: if errie = ? 1 ? , the spi generates an spi receiver/error cpu interrupt request. the spe bit is cleared. the spte bit is set. the spi state counter is cleared. the data direction register of the shared i/o port regains control of port drivers. note: to prevent bus contention with another master spi after a mode fault error, clear all data direction register (ddr) bits associated with the spi shared port pins. note: setting the modf flag (spscr) does not clear the spmstr bit. reading spmstr when modf = 1 will indicate a mode fault error occurred in either master mode or slave mode. when configured as a slave (spmstr = ? 0 ? ), the modf flag is set if ss goes high during a transmission. when cpha = ? 0 ? , a transmission begins when ss goes low and ends once the incoming spsck goes back to its idle level following the shift of the eighth data bit. when cpha = ? 1 ? , the transmission begins when the spsck leaves its idle level and ss is already low. the transmission continues until the spsck returns to its idle level following the shift of the last data bit. see transmission formats on page 234. note: when cpha = ? 0 ? , a modf occurs if a slave is selected (ss is at logic ? 0 ? ) and later deselected (ss is at logic ? 1 ? ) even if no spsck is sent to that slave. this happens because ss at logic ? 0 ? indicates the start of the transmission (miso driven out with the value of msb) for cpha = ? 0 ? . when cpha = ? 1 ? , a slave can be selected and then later deselected with no transmission occurring. therefore, modf does not occur since a transmission was never begun. in a slave spi (mstr = ? 0 ? ), the modf bit generates an spi receiver/error cpu interrupt request if the errie bit is set. the modf serial peripheral interface (spi) interrupts MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 243 bit does not clear the spe bit or reset the spi in any way. software can abort the spi transmission by toggling the spe bit of the slave. note: a logic ? 1 ? on the ss pin of a slave spi puts the miso pin in a high impedance state. also, the slave spi ignores all incoming spsck clocks, even if a transmission has begun. to clear the modf flag, read the spscr and then write to the spcr register. this entire clearing procedure must occur with no modf condition existing or else the flag will not be cleared. 16.7 interrupts four spi status flags can be enabled to generate cpu interrupt requests: the spi transmitter interrupt enable bit (sptie) enables the spte flag to generate transmitter cpu interrupt requests. the spi receiver interrupt enable bit (sprie) enables the sprf bit to generate receiver cpu interrupt requests, provided that the spi is enabled (spe = 1). the error interrupt enable bit (errie) enables both the modf and ovrf flags to generate a receiver/error cpu interrupt request. the mode fault enable bit (modfen) can prevent the modf flag from being set so that only the ovrf flag is enabled to generate receiver/error cpu interrupt requests. table 16-3. spi interrupts flag request spte (transmitter empty) spi transmitter cpu interrupt request (sptie = 1) sprf (receiver full) spi receiver cpu interrupt request (sprie = 1) ovrf (overflow) spi receiver/error interrupt request (sprie = 1, errie = 1) modf (mode fault) spi receiver/error interrupt request (sprie = 1, errie = 1, modfen = ? 1 ? ) serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 244 serial peripheral interface (spi) motorola figure 16-9. spi interrupt request generation two sources in the spi status and control register can generate cpu interrupt requests: spi receiver full bit (sprf) ? the sprf bit becomes set every time a byte transfers from the shift register to the receive data register. if the spi receiver interrupt enable bit, sprie, is also set, sprf can generate an spi receiver/error cpu interrupt request. spi transmitter empty (spte) ? the spte bit becomes set every time a byte transfers from the transmit data register to the shift register. if the spi transmit interrupt enable bit, sptie, is also set, spte can generate an spte cpu interrupt request. 16.8 queuing transmission data the double-buffered transmit data register allows a data byte to be queued and transmitted. for an spi configured as a master, a queued data byte is transmitted immediately after the previous transmission has completed. the spi transmitter empty flag (spte) indicates when the transmit data buffer is ready to accept new data. write to the spi data register only when the spte bit is high. figure 16-10 shows the timing associated with doing back-to-back transmissions with the spi (spsck has cpha: cpol = 1:0). spte sptie sprf sprie errie modf ovrf spe spi transmitter cpu interrupt request spi receiver/error cpu interrupt request serial peripheral interface (spi) queuing transmission data MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 245 for a slave, the transmit data buffer allows back-to-back transmissions to occur without the slave having to time the write of its data between the transmissions. also, if no new data is written to the data buffer, the last value contained in the shift register will be the next data word transmitted. figure 16-10. sprf/spte cpu interrupt timing bit 3 mosi sck (cpha:cpol = ? 1 ? :0) spte write to spdr 1 cpu writes byte 2 to spdr, queueing cpu writes byte 1 to spdr, clearing byte 1 transfers from transmit data 3 1 2 2 3 5 spte bit. register to shift register, setting spte bit. sprf read spscr msb bit 6 bit 5 bit 4 bit 2 bit 1 lsb msb bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 lsb msb bit 6 byte 2 transfers from transmit data cpu writes byte 3 to spdr, queueing byte 3 transfers from transmit data 5 8 10 8 10 4 first incoming byte transfers from shift 6 cpu reads spscr with sprf bit set. 4 6 9 second incoming byte transfers from shift 9 11 byte 2 and clearing spte bit. register to shift register, setting spte bit. register to receive data register, setting sprf bit. byte 3 and clearing spte bit. register to shift register, setting spte bit. register to receive data register, setting sprf bit. 12 cpu reads spdr, clearing sprf bit. bit 5 bit 4 byte 1byte 2byte 3 7 12 read spdr 7 cpu reads spdr, clearing sprf bit. 11 cpu reads spscr with sprf bit set. serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 246 serial peripheral interface (spi) motorola 16.9 resetting the spi any system reset completely resets the spi. partial resets occur whenever the spi enable bit (spe) is low. whenever spe is low, the following occurs: the spte flag is set any transmission currently in progress is aborted the shift register is cleared the spi state counter is cleared, making it ready for a new complete transmission all the spi port logic is defaulted back to being general purpose i/o. the following items are reset only by a system reset: all control bits in the spcr register all control bits in the spscr register (modfen, errie, spr1, and spr0) the status flags sprf, ovrf, and modf by not resetting the control bits when spe is low, the user can clear spe between transmissions without having to set all control bits again when spe is set back high for the next transmission. by not resetting the sprf, ovrf, and modf flags, the user can still service these interrupts after the spi has been disabled. the user can disable the spi by writing ? 0 ? to the spe bit. the spi can also be disabled by a mode fault occurring in an spi that was configured as a master with the modfen bit set. serial peripheral interface (spi) low-power modes MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 247 16.10 low-power modes the wait and stop instructions put the mcu in low power- consumption standby modes. 16.10.1 wait mode the spi module remains active after the execution of a wait instruction. in wait mode the spi module registers are not accessible by the cpu. any enabled cpu interrupt request from the spi module can bring the mcu out of wait mode. if spi module functions are not required during wait mode, power consumption can be reduced by disabling the spi module before executing the wait instruction. to exit wait mode when an overflow condition occurs, the ovrf bit should be enabled to generate cpu interrupt requests by setting the error interrupt enable bit (errie). see interrupts on page 243. 16.10.2 stop mode the spi module is inactive after the execution of a stop instruction. the stop instruction does not affect register conditions. spi operation resumes after an external interrupt. if stop mode is exited by reset, any transfer in progress is aborted, and the spi is reset. 16.11 spi during break interrupts the system integration module (sim) controls whether status bits in other modules can be cleared during the break state. the bcfe bit in the sim break flag control register (sbfcr) enables software to clear status bits during the break state. see sim break flag control register (sbfcr) on page 115. to allow software to clear status bits during a break interrupt, a ? 1 ? should be written to the bcfe bit. if a status bit is cleared during the break state, it remains cleared when the mcu exits the break state. serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 248 serial peripheral interface (spi) motorola to protect status bits during the break state, a ? 0 ? should be written to the bcfe bit. with bcfe at ? 0 ? (its default state), software can read and write i/o registers during the break state without affecting status bits. some status bits have a two-step read/write clearing procedure. if software does the first step on such a bit before the break, the bit cannot change during the break state as long as bcfe is a ? 0 ? . after the break, the second step clears the status bit. since the spte bit cannot be cleared during a break with the bcfe bit cleared, a write to the data register in break mode will not initiate a transmission, nor will this data be transferred into the shift register. therefore, a write to the spdr in break mode with the bcfe bit cleared has no effect. 16.12 i/o signals the spi module has five i/o pins and shares four of them with a parallel i/o port. miso ? data received mosi ? data transmitted spsck ? serial clock ss ? slave select v ss ? clock ground the spi has limited inter-integrated circuit (i 2 c) capability (requiring software support) as a master in a single-master environment. to communicate with i 2 c peripherals, mosi becomes an open-drain output when the spwom bit in the spi control register is set. in i 2 c communication, the mosi and miso pins are connected to a bidirectional pin from the i 2 c peripheral and through a pullup resistor to v dd . serial peripheral interface (spi) i/o signals MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 249 16.12.1 miso (masterin/slave out) miso is one of the two spi module pins that transmits serial data. in full duplex operation, the miso pin of the master spi module is connected to the miso pin of the slave spi module. the master spi simultaneously receives data on its miso pin and transmits data from its mosi pin. slave output data on the miso pin is enabled only when the spi is configured as a slave. the spi is configured as a slave when its spmstr bit is logic ? 0 ? and its ss pin is at locic ? 0 ? . to support a multiple- slave system, a logic ? 1 ? on the ss pin puts the miso pin in a high- impedance state. when enabled, the spi controls data direction of the miso pin regardless of the state of the data direction register of the shared i/o port. 16.12.2 mosi (master out/slave in) mosi is one of the two spi module pins that transmits serial data. in full duplex operation, the mosi pin of the master spi module is connected to the mosi pin of the slave spi module. the master spi simultaneously transmits data from its mosi pin and receives data on its miso pin. when enabled, the spi controls data direction of the mosi pin regardless of the state of the data direction register of the shared i/o port. 16.12.3 spsck (serial clock) the serial clock synchronizes data transmission between master and slave devices. in a master mcu, the spsck pin is the clock output. in a slave mcu, the spsck pin is the clock input. in full duplex operation, the master and slave mcus exchange a byte of data in eight serial clock cycles. when enabled, the spi controls data direction of the spsck pin regardless of the state of the data direction register of the shared i/o port. serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 250 serial peripheral interface (spi) motorola 16.12.4 ss (slave select) the ss pin has various functions depending on the current state of the spi. for an spi configured as a slave, the ss is used to select a slave. for cpha = ? 0 ? , the ss is used to define the start of a transmission. see transmission formats on page 234. since it is used to indicate the start of a transmission, the ss must be toggled high and low between each byte transmitted for the cpha = ? 0 ? format. however, it can remain low throughout the transmission for the cpha = ? 1 ? format. see figure 16-11 . figure 16-11. cpha/ss timing when an spi is configured as a slave, the ss pin is always configured as an input. it cannot be used as a general purpose i/o regardless of the state of the modfen control bit. however, the modfen bit can still prevent the state of the ss from creating a modf error. see spi status and control register (spscr) on page 254. note: a logic ? 1 ? on the ss pin of a slave spi puts the miso pin in a high- impedance state. the slave spi ignores all incoming spsck clocks, even if transmission has already begun. when an spi is configured as a master, the ss input can be used in conjunction with the modf flag to prevent multiple masters from driving mosi and spsck. see mode fault error on page 241. for the state of the ss pin to set the modf flag, the modfen bit in the spsck register must be set. if the modfen bit is low for an spi master, the ss pin can be used as a general purpose i/o under the control of the data direction register of the shared i/o port. with modfen high, it is an input-only pin byte 1 byte 3 miso/mosi byte 2 master ss slave ss (cpha = ? 0 ? ) slave ss (cpha = ? 1 ? ) serial peripheral interface (spi) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 251 to the spi regardless of the state of the data direction register of the shared i/o port. the cpu can always read the state of the ss pin by configuring the appropriate pin as an input and reading the data register. see table 16- 4 . 16.12.5 v ss (clock ground) v ss is the ground return for the serial clock pin, spsck, and the ground for the port output buffers. to reduce the ground return path loop and minimize radio frequency (rf) emissions, connect the ground pin of the slave to the v ss pin. 16.13 i/o registers three registers control and monitor spi operation: spi control register (spcr) spi status and control register (spscr) spi data register (spdr) table 16-4. spi configuration spe spmstr modfen spi configuration state of ss logic 0 x x not enabled general-purpose i/o; ss ignored by spi 1 0 x slave input-only to spi 1 1 0 master without modf general-purpose i/o; ss ignored by spi 1 1 1 master with modf input-only to spi x = don ? t care serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 252 serial peripheral interface (spi) motorola 16.13.1 spi control register (spcr) the spi control register does the following: enables spi module interrupt requests selects cpu interrupt requests configures the spi module as master or slave selects serial clock polarity and phase configures the spsck, mosi, and miso pins as open-drain outputs enables the spi module sprie ? spi receiver interrupt enable this read/write bit enables cpu interrupt requests generated by the sprf bit. the sprf bit is set when a byte transfers from the shift register to the receive data register. reset clears the sprie bit. 1 = sprf cpu interrupt requests enabled 0 = sprf cpu interrupt requests disabled spmstr ? spi master this read/write bit selects master mode operation or slave mode operation. reset sets the spmstr bit. 1 = master mode 0 = slave mode bit 7 6 5 4 3 2 1 bit 0 spcr read: sprie r spmstr cpol cpha spwom spe sptie write: reset:00 1 01000 r= reserved figure 16-12. spi control register (spcr) serial peripheral interface (spi) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 253 cpol ? clock polarity this read/write bit determines the logic state of the spsck pin between transmissions. see figure 16-4 and figure 16-5 . to transmit data between spi modules, the spi modules must have identical cpol bits. reset clears the cpol bit. cpha ? clock phase this read/write bit controls the timing relationship between the serial clock and spi data. see figure 16-4 and figure 16-5 . to transmit data between spi modules, the spi modules must have identical cpha bits. when cpha = ? 0 ? , the ss pin of the slave spi module must be set to logic one between bytes. see figure 16-11 . reset sets the cpha bit. when cpha = ? 0 ? for a slave, the falling edge of ss indicates the beginning of the transmission. this causes the spi to leave its idle state and begin driving the miso pin with the msb of its data. once the transmission begins, no new data is allowed into the shift register from the data register. therefore, the slave data register must be loaded with the desired transmit data before the falling edge of ss . any data written after the falling edge is stored in the data register and transferred to the shift register at the current transmission. when cpha = ? 1 ? for a slave, the first edge of the spsck indicates the beginning of the transmission. the same applies when ss is high for a slave. the miso pin is held in a high-impedance state, and the incoming spsck is ignored. in certain cases, it may also cause the modf flag to be set. see mode fault error on page 241. a logic ? 1 ? on the ss pin does not affect the state of the spi state machine in any way. spwom ? spi wired-or mode this read/write bit disables the pull-up devices on pins spsck, mosi, and miso so that those pins become open-drain outputs. 1 = wired-or spsck, mosi, and miso pins 0 = normal push-pull spsck, mosi, and miso pins serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 254 serial peripheral interface (spi) motorola spe ? spi enable this read/write bit enables the spi module. clearing spe causes a partial reset of the spi. see resetting the spi on page 246. reset clears the spe bit. 1 = spi module enabled 0 = spi module disabled sptie ? spi transmit interrupt enable this read/write bit enables cpu interrupt requests generated by the spte bit. spte is set when a byte transfers from the transmit data register to the shift register. reset clears the sptie bit. 1 = spte cpu interrupt requests enabled 0 = spte cpu interrupt requests disabled 16.13.2 spi status and control register (spscr) the spi status and control register contains flags to signal the following conditions: receive data register full failure to clear sprf bit before next byte is received (overflow error) inconsistent logic level on ss pin (mode fault error) transmit data register empty serial peripheral interface (spi) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 255 the spi status and control register also contains bits that perform the following functions: enable error interrupts enable mode fault error detection select master spi baud rate sprf ? spi receiver full this clearable, read-only flag is set each time a byte transfers from the shift register to the receive data register. sprf generates a cpu interrupt request if the sprie bit in the spi control register is set also. during an sprf cpu interrupt, the cpu clears sprf by reading the spi status and control register with sprf set and then reading the spi data register. any read of the spi data register clears the sprf bit. reset clears the sprf bit. 1 = receive data register full 0 = receive data register not full errie ? error interrupt enable this read-only bit enables the modf and ovrf flags to generate cpu interrupt requests. reset clears the errie bit. 1 = modf and ovrf can generate cpu interrupt requests 0 = modf and ovrf cannot generate cpu interrupt requests ovrf ? overflow flag this clearable, read-only flag is set if software does not read the byte in the receive data register before the next byte enters the shift register. in an overflow condition, the byte already in the receive data bit 7654321bit 0 spscr read: sprf errie ovrf modf spte modfe n spr1 spr0 write: reset:00001000 r= reserved = unimplemented figure 16-13. spi status and control register (spscr) serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 256 serial peripheral interface (spi) motorola register is unaffected, and the byte that shifted in last is lost. clear the ovrf bit by reading the spi status and control register with ovrf set and then reading the spi data register. reset clears the ovrf flag. 1 = overflow 0 = no overflow modf ? mode fault this clearable, ready-only flag is set in a slave spi if the ss pin goes high during a transmission. in a master spi, the modf flag is set if the ss pin goes low at any time. clear the modf bit by reading the spi status and control register with modf set and then writing to the spi data register. reset clears the modf bit. 1 = ss pin at inappropriate logic level 0 = ss pin at appropriate logic level spte ? spi transmitter empty this clearable, read-only flag is set each time the transmit data register transfers a byte into the shift register. spte generates an spte cpu interrupt request if the sptie bit in the spi control register is set also. note: the spi data register should not be written to unless the spte bit is high. for an idle master or idle slave that has no data loaded into its transmit buffer, the spte will be set again within two bus cycles since the transmit buffer empties into the shift register. this allows the user to queue up a 16-bit value to send. for an already active slave, the load of the shift register cannot occur until the transmission is completed. this implies that a back-to-back write to the transmit data register is not possible. the spte indicates when the next write can occur. reset sets the spte bit. 1 = transmit data register empty 0 = transmit data register not empty serial peripheral interface (spi) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola serial peripheral interface (spi) 257 modfen ? mode fault enable this read/write bit, when set to ? 1 ? , allows the modf flag to be set. if the modf flag is set, clearing the modfen does not clear the modf flag. if the spi is enabled as a master and the modfen bit is low, then the ss pin is available as a general purpose i/o. if the modfen bit is set, then this pin is not available as a general purpose i/o. when the spi is enabled as a slave, the ss pin is not available as a general purpose i/o regardless of the value of modfen. see ss (slave select) on page 250. if the modfen bit is low, the level of the ss pin does not affect the operation of an enabled spi configured as a master. for an enabled spi configured as a slave, having modfen low only prevents the modf flag from being set. it does not affect any other part of spi operation. see mode fault error on page 241. spr1 and spr0 ? spi baud rate select in master mode, these read/write bits select one of four baud rates as shown in table 16-5 . spr1 and spr0 have no effect in slave mode. reset clears spr1 and spr0. the following formula is used to calculate the spi baud rate: where: cgmout = base clock output of the clock generator module (cgm) bd = baud rate divisor table 16-5. spi master baud rate selection spr1:spr0 baud rate divisor (bd) 00 2 01 8 10 32 11 128 baud rate cgmout 2bd --------------------------- = serial peripheral interface (spi) technical data MC68HC08AZ32A ? rev 1.0 258 serial peripheral interface (spi) motorola 16.13.3 spi data register (spdr) the spi data register is the read/write buffer for the receive data register and the transmit data register. writing to the spi data register writes data into the transmit data register. reading the spi data register reads data from the receive data register. the transmit data and receive data registers are separate buffers that can contain different values. see figure 16-2 . r7:r0/t7:t0 ? receive/transmit data bits note: do not use read-modify-write instructions on the spi data register since the buffer read is not the same as the buffer written. bit 7654321bit 0 spdr read: r7 r6 r5 r4 r3 r2 r1 r0 write: t7 t6 t5 t4 t3 t2 t1 t0 reset: indeterminate after reset figure 16-14. spi data register (spdr) MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 259 technical data ? MC68HC08AZ32A section 17. timer interface module b (timb) 17.1 contents 17.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260 17.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260 17.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262 17.4.1 timb counter prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . 262 17.4.2 input capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263 17.4.3 output compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 17.4.3.1 unbuffered output compare . . . . . . . . . . . . . . . . . . . . 264 17.4.3.2 buffered output compare . . . . . . . . . . . . . . . . . . . . . . 265 17.4.4 pulse width modulation (pwm) . . . . . . . . . . . . . . . . . . . 266 17.4.4.1 unbuffered pwm signal generation . . . . . . . . . . . . . 267 17.4.4.2 buffered pwm signal generation . . . . . . . . . . . . . . . . 268 17.4.4.3 pwm initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268 17.5 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 17.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 17.6.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 17.6.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 17.7 timb during break interrupts . . . . . . . . . . . . . . . . . . . . . . . 271 17.8 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 17.8.1 timb clock pin (ptd4/atd12/tbclk) . . . . . . . . . . . . . . 271 17.8.2 timb channel i/o pins (ptf5/tbch1 ? ptf4/tbch0) . . 272 17.9 i/o registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272 17.9.1 timb status and control register . . . . . . . . . . . . . . . . . 273 17.9.2 timb counter registers . . . . . . . . . . . . . . . . . . . . . . . . . 275 17.9.3 timb counter modulo registers . . . . . . . . . . . . . . . . . . . 276 17.9.4 timb channel status and control registers . . . . . . . . . 277 17.9.5 timb channel registers . . . . . . . . . . . . . . . . . . . . . . . . . 281 timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 260 timer interface module b (timb) motorola 17.2 introduction this section describes the timer interface module (timb). the timb is a 2-channel timer that provides a timing reference with input capture, output compare and pulse width modulation functions. figure 17-1 is a block diagram of the timb. for further information regarding timers on m68hc08 family devices, please consult the hc08 timer reference manual, tim08rm/ad. 17.3 features features of the timb include: two input capture/output compare channels ? rising-edge, falling-edge or any-edge input capture trigger ? set, clear or toggle output compare action buffered and unbuffered pulse width modulation (pwm) signal generation programmable timb clock input ? 7 frequency internal bus clock prescaler selection ? external timb clock input (4 mhz maximum frequency) free-running or modulo up-count operation toggle any channel pin on overflow timb counter stop and reset bits timer interface module b (timb) features MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 261 figure 17-1. timb block diagram figure 17-2. timb i/o register summary addr. register name bit 7 6 5 4 3 2 1 bit 0 $0040 timb status/control register (tbsc) r: tof toie tstop 00 ps2 ps1 ps0 w: 0trstr $0041 timb counter register high (tbcnth) r: bit 15 14 13 12 11 10 9 bit 8 w: rrrrrrrr $0042 timb counter register low (tbcntl) r: bit 7654321bit 0 w: rrrrrrrr $0043 timb counter modulo reg. high (tbmodh) r: bit 15 14 13 12 11 10 9 bit 8 w: $0044 timb counter modulo reg. low (tbmodl) r: bit 7654321bit 0 w: $0045 timb ch. 0 status/control register (tbsc0) r: ch0f ch0ie ms0b ms0a els0b els0a tov0 ch0max w: 0 $0046 timb ch. 0 register high (tbch0h) r: bit 15 14 13 12 11 10 9 bit 8 w: prescaler prescaler select tclk internal 16-bit comparator ps2 ps1 ps0 16-bit comparator 16-bit latch tch0h:tch0l ms0a els0b els0a ptf4 tof toie inter- channel 0 tmodh:tmodl trst tstop tov0 ch0ie ch0f ch0max ms0b 16-bit counter bus clock ptd4/atd12/tbclk ptf4/tbch0 ptf5/tbch1 logic rupt logic inter- rupt logic 16-bit comparator 16-bit latch tch1h:tch1l ms1a els1b els1a ptf5 channel 1 tov1 ch1ie ch1f ch1max logic inter- rupt logic timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 262 timer interface module b (timb) motorola 17.4 functional description figure 17-1 shows the timb structure. the central component of the timb is the 16-bit timb counter that can operate as a free-running counter or a modulo up-counter. the timb counter provides the timing reference for the input capture and output compare functions. the timb counter modulo registers, tbmodh ? tbmodl, control the modulo value of the timb counter. software can read the timb counter value at any time without affecting the counting sequence. the two timb channels are programmable independently as input capture or output compare channels. 17.4.1 timb counter prescaler the timb clock source can be one of the seven prescaler outputs or the timb clock pin, ptd4/atd12/tbclk. the prescaler generates seven clock rates from the internal bus clock. the prescaler select bits, ps[2:0], in the timb status and control register select the timb clock source. $0047 timb ch. 0 register low (tbch0l) r: bit 7654321bit 0 w: $0048 timb ch. 1 status/control register (tbsc1) r: ch1f ch1ie 0 ms1a els1b els1a tov1 ch1max w: 0r $0049 timb ch. 1 register high (tbch1h) r: bit 15 14 13 12 11 10 9 bit 8 w: $004a timb ch. 1 register low (tbch1l) r: bit 7654321bit 0 w: r= reserved figure 17-2. timb i/o register summary addr. register name bit 7 6 5 4 3 2 1 bit 0 timer interface module b (timb) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 263 17.4.2 input capture an input capture function has three basic parts: edge select logic, an input capture latch and a 16-bit counter. two 8-bit registers, which make up the 16-bit input capture register, are used to latch the value of the free-running counter after the corresponding input capture edge detector senses a defined transition. the polarity of the active edge is programmable. the level transition which triggers the counter transfer is defined by the corresponding input edge bits (elsxb and elsxa in tbsc0 through tbsc1 control registers with x referring to the active channel number). when an active edge occurs on the pin of an input capture channel, the timb latches the contents of the timb counter into the timb channel registers, tbchxh ? tbchxl. input captures can generate timb cpu interrupt requests. software can determine that an input capture event has occurred by enabling input capture interrupts or by polling the status flag bit. the free-running counter contents are transferred to the timb channel register (tbchxh ? tbchxl, see timb channel registers on page 281) on each proper signal transition regardless of whether the timb channel flag (ch0f ? ch1f in tbsc0 ? tbsc1 registers) is set or clear. when the status flag is set, a cpu interrupt is generated if enabled. the value of the count latched or ? captured ? is the time of the event. because this value is stored in the input capture register 2 bus cycles after the actual event occurs, user software can respond to this event at a later time and determine the actual time of the event. however, this must be done prior to another input capture on the same pin; otherwise, the previous time value will be lost. by recording the times for successive edges on an incoming signal, software can determine the period and/or pulse width of the signal. to measure a period, two successive edges of the same polarity are captured. to measure a pulse width, two alternate polarity edges are captured. software should track the overflows at the 16-bit module counter to extend its range. another use for the input capture function is to establish a time reference. in this case, an input capture function is used in conjunction with an output compare function. for example, to activate an output signal a specified number of clock cycles after detecting an input event timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 264 timer interface module b (timb) motorola (edge), use the input capture function to record the time at which the edge occurred. a number corresponding to the desired delay is added to this captured value and stored to an output compare register (see timb channel registers on page 281). because both input captures and output compares are referenced to the same 16-bit modulo counter, the delay can be controlled to the resolution of the counter independent of software latencies. reset does not affect the contents of the input capture channel register (tbchxh ? tbchxl). 17.4.3 output compare with the output compare function, the timb can generate a periodic pulse with a programmable polarity, duration and frequency. when the counter reaches the value in the registers of an output compare channel, the timb can set, clear or toggle the channel pin. output compares can generate timb cpu interrupt requests. 17.4.3.1 unbuffered output compare any output compare channel can generate unbuffered output compare pulses as described in output compare on page 264. the pulses are unbuffered because changing the output compare value requires writing the new value over the old value currently in the timb channel registers. an unsynchronized write to the timb channel registers to change an output compare value could cause incorrect operation for up to two counter overflow periods. for example, writing a new value before the counter reaches the old value but after the counter reaches the new value prevents any compare during that counter overflow period. also, using a timb overflow interrupt routine to write a new, smaller output compare value may cause the compare to be missed. the timb may pass the new value before it is written. use the following methods to synchronize unbuffered changes in the output compare value on channel x: timer interface module b (timb) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 265 when changing to a smaller value, enable channel x output compare interrupts and write the new value in the output compare interrupt routine. the output compare interrupt occurs at the end of the current output compare pulse. the interrupt routine has until the end of the counter overflow period to write the new value. when changing to a larger output compare value, enable timb overflow interrupts and write the new value in the timb overflow interrupt routine. the timb overflow interrupt occurs at the end of the current counter overflow period. writing a larger value in an output compare interrupt routine (at the end of the current pulse) could cause two output compares to occur in the same counter overflow period. 17.4.3.2 buffered output compare channels 0 and 1 can be linked to form a buffered output compare channel whose output appears on the ptf4/tbch0 pin. the timb channel registers of the linked pair alternately control the output. setting the ms0b bit in timb channel 0 status and control register (tbsc0) links channel 0 and channel 1. the output compare value in the timb channel 0 registers initially controls the output on the ptf4/tbch0 pin. writing to the timb channel 1 registers enables the timb channel 1 registers to synchronously control the output after the timb overflows. at each subsequent overflow, the timb channel registers (0 or 1) that control the output are the ones written to last. tbsc0 controls and monitors the buffered output compare function and timb channel 1 status and control register (tbsc1) is unused. while the ms0b bit is set, the channel 1 pin, ptf5/tbch1, is available as a general-purpose i/o pin. note: in buffered output compare operation, do not write new output compare values to the currently active channel registers. user software should track the currently active channel to prevent writing a new value to the active channel. writing to the active channel registers is the same as generating unbuffered output compares. timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 266 timer interface module b (timb) motorola 17.4.4 pulse width modulation (pwm) by using the toggle-on-overflow feature with an output compare channel, the timb can generate a pwm signal. the value in the timb counter modulo registers determines the period of the pwm signal. the channel pin toggles when the counter reaches the value in the timb counter modulo registers. the time between overflows is the period of the pwm signal. as figure 17-3 shows, the output compare value in the timb channel registers determines the pulse width of the pwm signal. the time between overflow and output compare is the pulse width. program the timb to clear the channel pin on output compare if the state of the pwm pulse is logic 1. program the timb to set the pin if the state of the pwm pulse is logic 0. figure 17-3. pwm period and pulse width the value in the timb counter modulo registers and the selected prescaler output determines the frequency of the pwm output. the frequency of an 8-bit pwm signal is variable in 256 increments. writing $00ff (255) to the timb counter modulo registers produces a pwm period of 256 times the internal bus clock period if the prescaler select value is $000 (see timb status and control register). the value in the timb channel registers determines the pulse width of the pwm output. the pulse width of an 8-bit pwm signal is variable in 256 increments. writing $0080 (128) to the timb channel registers produces a duty cycle of 128/256 or 50%. ptex/tchx period pulse width overflow overflow overflow output compare output compare output compare timer interface module b (timb) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 267 17.4.4.1 unbuffered pwm signal generation any output compare channel can generate unbuffered pwm pulses as described in pulse width modulation (pwm) on page 266. the pulses are unbuffered because changing the pulse width requires writing the new pulse width value over the value currently in the timb channel registers. an unsynchronized write to the timb channel registers to change a pulse width value could cause incorrect operation for up to two pwm periods. for example, writing a new value before the counter reaches the old value but after the counter reaches the new value prevents any compare during that pwm period. also, using a timb overflow interrupt routine to write a new, smaller pulse width value may cause the compare to be missed. the timb may pass the new value before it is written to the timb channel registers. use the following methods to synchronize unbuffered changes in the pwm pulse width on channel x: when changing to a shorter pulse width, enable channel x output compare interrupts and write the new value in the output compare interrupt routine. the output compare interrupt occurs at the end of the current pulse. the interrupt routine has until the end of the pwm period to write the new value. when changing to a longer pulse width, enable timb overflow interrupts and write the new value in the timb overflow interrupt routine. the timb overflow interrupt occurs at the end of the current pwm period. writing a larger value in an output compare interrupt routine (at the end of the current pulse) could cause two output compares to occur in the same pwm period. note: in pwm signal generation, do not program the pwm channel to toggle on output compare. toggling on output compare prevents reliable 0% duty cycle generation and removes the ability of the channel to self- correct in the event of software error or noise. toggling on output compare also can cause incorrect pwm signal generation when changing the pwm pulse width to a new, much larger value. timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 268 timer interface module b (timb) motorola 17.4.4.2 buffered pwm signal generation channels 0 and 1 can be linked to form a buffered pwm channel whose output appears on the ptf4/tbch0 pin. the timb channel registers of the linked pair alternately control the pulse width of the output. setting the ms0b bit in timb channel 0 status and control register (tbsc0) links channel 0 and channel 1. the timb channel 0 registers initially control the pulse width on the ptf4/tbch0 pin. writing to the timb channel 1 registers enables the timb channel 1 registers to synchronously control the pulse width at the beginning of the next pwm period. at each subsequent overflow, the timb channel registers (0 or 1) that control the pulse width are the ones written to last. tbsc0 controls and monitors the buffered pwm function, and timb channel 1 status and control register (tbsc1) is unused. while the ms0b bit is set, the channel 1 pin, ptf5/tbch1, is available as a general-purpose i/o pin. note: in buffered pwm signal generation, do not write new pulse width values to the currently active channel registers. user software should track the currently active channel to prevent writing a new value to the active channel. writing to the active channel registers is the same as generating unbuffered pwm signals. 17.4.4.3 pwm initialization to ensure correct operation when generating unbuffered or buffered pwm signals, use the following initialization procedure: 1. in the timb status and control register (tbsc): a. stop the timb counter by setting the timb stop bit, tstop. b. reset the timb counter and prescaler by setting the timb reset bit, trst. 2. in the timb counter modulo registers (tbmodh ? tbmodl) write the value for the required pwm period. 3. in the timb channel x registers (tbchxh ? tbchxl) write the value for the required pulse width. timer interface module b (timb) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 269 4. in timb channel x status and control register (tbscx): a. write 0:1 (for unbuffered output compare or pwm signals) or 1:0 (for buffered output compare or pwm signals) to the mode select bits, msxb ? msxa (see table 17-2 ). b. write 1 to the toggle-on-overflow bit, tovx. c. write 1:0 (to clear output on compare) or 1:1 (to set output on compare) to the edge/level select bits, elsxb ? elsxa. the output action on compare must force the output to the complement of the pulse width level (see table 17-2 ). note: in pwm signal generation, do not program the pwm channel to toggle on output compare. toggling on output compare prevents reliable 0% duty cycle generation and removes the ability of the channel to self- correct in the event of software error or noise. toggling on output compare can also cause incorrect pwm signal generation when changing the pwm pulse width to a new, much larger value. 5. in the timb status control register (tbsc) clear the timb stop bit, tstop. setting ms0b links channels 0 and 1 and configures them for buffered pwm operation. the timb channel 0 registers (tbch0h ? tbch0l) initially control the buffered pwm output. timb status control register 0 (tbsc0) controls and monitors the pwm signal from the linked channels. ms0b takes priority over ms0a. clearing the toggle-on-overflow bit, tovx, inhibits output toggles on timb overflows. subsequent output compares try to force the output to a state it is already in and have no effect. the result is a 0% duty cycle output. setting the channel x maximum duty cycle bit (chxmax) and setting the tovx bit generates a 100% duty cycle output (see timb channel status and control registers on page 277). timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 270 timer interface module b (timb) motorola 17.5 interrupts the following timb sources can generate interrupt requests: timb overflow flag (tof) ? the tof bit is set when the timb counter value reaches the value in the timb counter modulo registers. the timb overflow interrupt enable bit, toie, enables timb overflow cpu interrupt requests. tof and toie are in the timb status and control register. timb channel flags (ch1f ? ch0f) ? the chxf bit is set when an input capture or output compare occurs on channel x. channel x timb cpu interrupt requests are controlled by the channel x interrupt enable bit, chxie. 17.6 low-power modes the wait and stop instructions put the mcu in low power- consumption standby modes. 17.6.1 wait mode the timb remains active after the execution of a wait instruction. in wait mode, the timb registers are not accessible by the cpu. any enabled cpu interrupt request from the timb can bring the mcu out of wait mode. if timb functions are not required during wait mode, reduce power consumption by stopping the timb before executing the wait instruction. 17.6.2 stop mode the timb is inactive after the execution of a stop instruction. the stop instruction does not affect register conditions or the state of the timb counter. timb operation resumes when the mcu exits stop mode. timer interface module b (timb) timb during break interrupts MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 271 17.7 timb during break interrupts a break interrupt stops the timb counter and inhibits input captures. the system integration module (sim) controls whether status bits in other modules can be cleared during the break state. the bcfe bit in the sim break flag control register (sbfcr) enables software to clear status bits during the break state (see sim break flag control register (sbfcr) on page 115). to allow software to clear status bits during a break interrupt, write a logic 1 to the bcfe bit. if a status bit is cleared during the break state, it remains cleared when the mcu exits the break state. to protect status bits during the break state, write a logic 0 to the bcfe bit. with bcfe at logic 0 (its default state), software can read and write i/o registers during the break state without affecting status bits. some status bits have a 2-step read/write clearing procedure. if software does the first step on such a bit before the break, the bit cannot change during the break state as long as bcfe is at logic 0. after the break, doing the second step clears the status bit. 17.8 i/o signals port d shares one of its pins with the timb. port f shares two of its pins with the timb. ptd4/atd12/tbclk is an external clock input to the timb prescaler. the two timb channel i/o pins are ptf4/tbch0 and ptf5/tbch1. 17.8.1 timb clock pin (ptd4/atd12/tbclk) ptd4/atd12/tbclk is an external clock input that can be the clock source for the timb counter instead of the prescaled internal bus clock. select the ptd4/atd12/tbclk input by writing logic 1s to the three prescaler select bits, ps[2:0] (see timb status and control register). the minimum tclk pulse width, tclk lmin or tclk hmin , is: 1 bus frequency ------------------------------------- t su + timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 272 timer interface module b (timb) motorola the maximum tclk frequency is the least: 4 mhz or bus frequency 2. ptd4/atd12/tbclk is available as a general-purpose i/o pin or adc channel when not used as the timb clock input. when the ptd4/atd12/tbclk pin is the timb clock input, it is an input regardless of the state of the ddrd4 bit in data direction register d. 17.8.2 timb channel i/o pins (ptf5/tbch1 ? ptf4/tbch0) each channel i/o pin is programmable independently as an input capture pin or an output compare pin. ptf4/tbch0 and ptf5/tbch1 can be configured as buffered output compare or buffered pwm pins. 17.9 i/o registers these i/o registers control and monitor timb operation: timb status and control register (tbsc) timb control registers (tbcnth ? tbcntl) timb counter modulo registers (tbmodh ? tbmodl) timb channel status and control registers (tbsc0 and tbsc1) timb channel registers (tbch0h ? tbch0l, tbch1h ? tbch1l) timer interface module b (timb) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 273 17.9.1 timb status and control register the timb status and control register: enables timb overflow interrupts flags timb overflows stops the timb counter resets the timb counter prescales the timb counter clock tof ? timb overflow flag bit this read/write flag is set when the timb counter reaches the modulo value programmed in the timb counter modulo registers. clear tof by reading the timb status and control register when tof is set and then writing a logic 0 to tof. if another timb overflow occurs before the clearing sequence is complete, then writing logic 0 to tof has no effect. therefore, a tof interrupt request cannot be lost due to inadvertent clearing of tof. reset clears the tof bit. writing a logic 1 to tof has no effect. 1 = timb counter has reached modulo value 0 = timb counter has not reached modulo value toie ? timb overflow interrupt enable bit this read/write bit enables timb overflow interrupts when the tof bit becomes set. reset clears the toie bit. 1 = timb overflow interrupts enabled 0 = timb overflow interrupts disabled address: $0040 bit 7654321bit 0 read: tof toie tstop 00 ps2 ps1 ps0 write: 0 trst r reset:00100000 r= reserved figure 17-4. timb status and control register (tbsc) timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 274 timer interface module b (timb) motorola tstop ? timb stop bit this read/write bit stops the timb counter. counting resumes when tstop is cleared. reset sets the tstop bit, stopping the timb counter until software clears the tstop bit. 1 = timb counter stopped 0 = timb counter active note: do not set the tstop bit before entering wait mode if the timb is required to exit wait mode. also, when the tstop bit is set and the timer is configured for input capture operation, input captures are inhibited until tstop is cleared. trst ? timb reset bit setting this write-only bit resets the timb counter and the timb prescaler. setting trst has no effect on any other registers. counting resumes from $0000. trst is cleared automatically after the timb counter is reset and always reads as logic 0. reset clears the trst bit. 1 = prescaler and timb counter cleared 0 = no effect note: setting the tstop and trst bits simultaneously stops the timb counter at a value of $0000. ps[2:0] ? prescaler select bits these read/write bits select either the ptd4/atd12/tbclk pin or one of the seven prescaler outputs as the input to the timb counter as table 17-1 shows. reset clears the ps[2:0] bits. table 17-1. prescaler selection ps[2:0] timb clock source 000 internal bus clock 1 001 internal bus clock 2 010 internal bus clock 4 011 internal bus clock 8 100 internal bus clock 16 101 internal bus clock 32 110 internal bus clock 64 111 ptd4/atd12/tbclk timer interface module b (timb) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 275 17.9.2 timb counter registers the two read-only timb counter registers contain the high and low bytes of the value in the timb counter. reading the high byte (tbcnth) latches the contents of the low byte (tbcntl) into a buffer. subsequent reads of tbcnth do not affect the latched tbcntl value until tbcntl is read. reset clears the timb counter registers. setting the timb reset bit (trst) also clears the timb counter registers. note: if tbcnth is read during a break interrupt, be sure to unlatch tbcntl by reading tbcntl before exiting the break interrupt. otherwise, tbcntl retains the value latched during the break. register name and address tbcnth ? $0041 bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write:rrrrrrrr reset:00000000 register name and address tbcntl ? $0042 bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write:rrrrrrrr reset:00000000 rr = reserved figure 17-5. timb counter registers (tbcnth and tbcntl) timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 276 timer interface module b (timb) motorola 17.9.3 timb counter modulo registers the read/write timb modulo registers contain the modulo value for the timb counter. when the timb counter reaches the modulo value, the overflow flag (tof) becomes set and the timb counter resumes counting from $0000 at the next timer clock. writing to the high byte (tbmodh) inhibits the tof bit and overflow interrupts until the low byte (tbmodl) is written. reset sets the timb counter modulo registers. note: reset the timb counter before writing to the timb counter modulo registers. register name and address tbmodh ? $0043 bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write: reset:11111111 register name and address tbmodl ? $0044 bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write: reset:11111111 figure 17-6. timb counter modulo registers (tbmodh and tbmodl) timer interface module b (timb) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 277 17.9.4 timb channel status and control registers each of the timb channel status and control registers: flags input captures and output compares enables input capture and output compare interrupts selects input capture, output compare or pwm operation selects high, low or toggling output on output compare selects rising edge, falling edge or any edge as the active input capture trigger selects output toggling on timb overflow selects 0% and 100% pwm duty cycle selects buffered or unbuffered output compare/pwm operation register name and address tbsc0 ? $0045 bit 7654321bit 0 read: ch0f ch0ie ms0b ms0a els0b els0a tov0 ch0max write: 0 reset:00000000 register name and address tbsc1 ? $0048 bit 7654321bit 0 read: ch1f ch1ie 0 ms1a els1b els1a tov1 ch1max write: 0 r reset:00000000 rr = reserved figure 17-7. timb channel status and control registers (tbsc0 ? tbsc1) timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 278 timer interface module b (timb) motorola chxf ? channel x flag bit when channel x is an input capture channel, this read/write bit is set when an active edge occurs on the channel x pin. when channel x is an output compare channel, chxf is set when the value in the timb counter registers matches the value in the timb channel x registers. when chxie = 1, clear chxf by reading timb channel x status and control register with chxf set, and then writing a logic 0 to chxf. if another interrupt request occurs before the clearing sequence is complete, then writing logic 0 to chxf has no effect. therefore, an interrupt request cannot be lost due to inadvertent clearing of chxf. reset clears the chxf bit. writing a logic 1 to chxf has no effect. 1 = input capture or output compare on channel x 0 = no input capture or output compare on channel x chxie ? channel x interrupt enable bit this read/write bit enables timb cpu interrupts on channel x. reset clears the chxie bit. 1 = channel x cpu interrupt requests enabled 0 = channel x cpu interrupt requests disabled msxb ? mode select bit b this read/write bit selects buffered output compare/pwm operation. msxb exists only in the timb channel 0. setting ms0b disables the channel 1 status and control register and reverts tbch1 to general-purpose i/o. reset clears the msxb bit. 1 = buffered output compare/pwm operation enabled 0 = buffered output compare/pwm operation disabled timer interface module b (timb) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 279 msxa ? mode select bit a when elsxb:a 00, this read/write bit selects either input capture operation or unbuffered output compare/pwm operation (see table 17-2 ). 1 = unbuffered output compare/pwm operation 0 = input capture operation when elsxb:a = 00, this read/write bit selects the initial output level of the tbchx pin once pwm, input capture or output compare operation is enabled (see table 17-2 ). reset clears the msxa bit. 1 = initial output level low 0 = initial output level high note: before changing a channel function by writing to the msxb or msxa bit, set the tstop and trst bits in the timb status and control register (tbsc). elsxb and elsxa ? edge/level select bits when channel x is an input capture channel, these read/write bits control the active edge-sensing logic on channel x. when channel x is an output compare channel, elsxb and elsxa control the channel x output behavior when an output compare occurs. when elsxb and elsxa are both clear, channel x is not connected to port f and pin ptfx/tbchx is available as a general-purpose i/o pin. however, channel x is at a state determined by these bits and becomes transparent to the respective pin when pwm, input capture, or output compare mode is enabled. table 17-2 shows how elsxb and elsxa work. reset clears the elsxb and elsxa bits. timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 280 timer interface module b (timb) motorola note: before enabling a timb channel register for input capture operation, make sure that the ptfx/tbchx pin is stable for at least two bus clocks. tovx ? toggle-on-overflow bit when channel x is an output compare channel, this read/write bit controls the behavior of the channel x output when the timb counter overflows. when channel x is an input capture channel, tovx has no effect. reset clears the tovx bit. 1 = channel x pin toggles on timb counter overflow. 0 = channel x pin does not toggle on timb counter overflow. note: when tovx is set, a timb counter overflow takes precedence over a channel x output compare if both occur at the same time. table 17-2. mode, edge, and level selection msxb:msxa elsxb:elsxa mode configuration x0 00 output preset pin under port control; initialize timer output level high x1 00 pin under port control; initialize timer output level low 00 01 input capture capture on rising edge only 00 10 capture on falling edge only 00 11 capture on rising or falling edge 01 01 output compare or pwm toggle output on compare 01 10 clear output on compare 01 11 set output on compare 1x 01 buffered output compare or buffered pwm toggle output on compare 1x 10 clear output on compare 1x 11 set output on compare timer interface module b (timb) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module b (timb) 281 chxmax ? channel x maximum duty cycle bit when the tovx bit is at logic 1, setting the chxmax bit forces the duty cycle of buffered and unbuffered pwm signals to 100%. as figure 17-8 shows, the chxmax bit takes effect in the cycle after it is set or cleared. the output stays at the 100% duty cycle level until the cycle after chxmax is cleared. figure 17-8. chxmax latency 17.9.5 timb channel registers these read/write registers contain the captured timb counter value of the input capture function or the output compare value of the output compare function. the state of the timb channel registers after reset is unknown. in input capture mode (msxb ? msxa = 0:0) reading the high byte of the timb channel x registers (tbchxh) inhibits input captures until the low byte (tbchxl) is read. in output compare mode (msxb ? msxa 0:0) writing to the high byte of the timb channel x registers (tbchxh) inhibits output compares and the chxf bit until the low byte (tbchxl) is written. output overflow ptex/tchx period chxmax overflow overflow overflow overflow compare output compare output compare output compare timer interface module b (timb) technical data MC68HC08AZ32A ? rev 1.0 282 timer interface module b (timb) motorola register name and address tbch0h ? $0046 bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write: reset: indeterminate after reset register name and address tbch0l ? $0047 bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write: reset: indeterminate after reset register name and address tbch1h ? $0049 bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write: reset: indeterminate after reset register name and address tbch1l ? $004a bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write: reset: indeterminate after reset figure 17-9. timb channel registers (tbch0h/l ? tbch1h/l) MC68HC08AZ32A ? rev 1.0 technical data motorola programmable interrupt timer (pit) 283 technical data ? MC68HC08AZ32A section 18. programmable interrupt timer (pit) 18.1 contents 18.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283 18.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284 18.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284 18.5 pit counter prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285 18.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 18.6.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 18.6.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 18.7 pit during break interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 286 18.8 i/o registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287 18.8.1 pit status and control register . . . . . . . . . . . . . . . . . . . 287 18.8.2 pit counter registers . . . . . . . . . . . . . . . . . . . . . . . . . . . 290 18.8.3 pit counter modulo registers . . . . . . . . . . . . . . . . . . . . 291 18.2 introduction this section describes the programmable interrupt timer (pit) which is a periodic interrupt timer whose counter is clocked internally via software programmable options. figure 18-1 is a block diagram of the pit. for further information regarding timers on m68hc08 family devices, please consult the hc08 timer reference manual, tim08rm/ad. programmable interrupt timer (pit) technical data MC68HC08AZ32A ? rev 1.0 284 programmable interrupt timer (pit) motorola 18.3 features features of the pit include: programmable pit clock input free-running or modulo up-count operation pit counter stop and reset bits 18.4 functional description figure 18-1 shows the structure of the pit. the central component of the pit is the 16-bit pit counter that can operate as a free-running counter or a modulo up-counter. the counter provides the timing reference for the interrupt. the pit counter modulo registers, pmodh ? pmodl, control the modulo value of the counter. software can read the counter value at any time without affecting the counting sequence. figure 18-1. pit block diagram prescaler prescaler select internal 16-bit comparator pps2 pps1 pps0 pof poie inter- pmodh:pmodl crst cstop 16-bit counter bus clock rupt logic programmable interrupt timer (pit) pit counter prescaler MC68HC08AZ32A ? rev 1.0 technical data motorola programmable interrupt timer (pit) 285 18.5 pit counter prescaler the clock source can be one of the seven prescaler outputs. the prescaler generates seven clock rates from the internal bus clock. the prescaler select bits, pps[2:0], in the status and control register select the pit clock source. the value in the pit counter modulo registers and the selected prescaler output determines the frequency of the periodic interrupt. the pit overflow flag (pof) is set when the pit counter value reaches the register name bit 7654321bit 0 pit status and control register (psc) read: pof poie pstop 00 pps2 pps1 pps0 write: 0 prst reset:00100000 pit counter register high (pcnth) read: bit 15 14 13 12 11 10 9 bit 8 write: reset:00000000 pit counter register low (pcntl) read: bit 7 654321bit 0 write: reset:00000000 pit counter modulo register high (pmodh) read: bit 15 14 13 12 11 10 9 bit 8 write: reset:11111111 pit counter modulo register low (pmodl) read: bit 7654321bit 0 write: reset:11111111 =unimplemented figure 18-2. pit i/o register summary table 18-1. pit i/o register address summary register psc pcnth pcntl pmodh pmodl address $004b $004c $004d $004e $004f programmable interrupt timer (pit) technical data MC68HC08AZ32A ? rev 1.0 286 programmable interrupt timer (pit) motorola modulo value programmed in the pit counter modulo registers. the pit interrupt enable bit, poie, enables pit overflow cpu interrupt requests. pof and poie are in the pit status and control register. 18.6 low-power modes the wait and stop instructions put the mcu in low power-consump- tion standby modes. 18.6.1 wait mode the pit remains active after the execution of a wait instruction. in wait mode the pit registers are not accessible by the cpu. any enabled cpu interrupt request from the pit can bring the mcu out of wait mode. if pit functions are not required during wait mode, reduce power consumption by stopping the pit before executing the wait instruction. 18.6.2 stop mode the pit is inactive after the execution of a stop instruction. the stop instruction does not affect register conditions or the state of the pit counter. pit operation resumes when the mcu exits stop mode after an external interrupt. 18.7 pit during break interrupts a break interrupt stops the pit counter. the system integration module (sim) controls whether status bits in other modules can be cleared during the break state. the bcfe bit in the sim break flag control register (sbfcr) enables software to clear status bits during the break state (see sim break flag control register (sbfcr) on page 115). programmable interrupt timer (pit) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola programmable interrupt timer (pit) 287 to allow software to clear status bits during a break interrupt, write a logic 1 to the bcfe bit. if a status bit is cleared during the break state, it remains cleared when the mcu exits the break state. to protect status bits during the break state, write a logic 0 to the bcfe bit. with bcfe at logic 0 (its default state), software can read and write i/o registers during the break state without affecting status bits. some status bits have a 2-step read/write clearing procedure. if software does the first step on such a bit before the break, the bit cannot change during the break state as long as bcfe is at logic 0. after the break, doing the second step clears the status bit. 18.8 i/o registers the following i/o registers control and monitor operation of the pit: pit status and control register (psc) pit counter registers (pcnth ? pcntl) pit counter modulo registers (pmodh ? pmodl) 18.8.1 pit status and control register the pit status and control register: enables pit interrupt flags pit overflows stops the pit counter resets the pit counter prescales the pit counter clock programmable interrupt timer (pit) technical data MC68HC08AZ32A ? rev 1.0 288 programmable interrupt timer (pit) motorola pof ? pit overflow flag bit this read/write flag is set when the pit counter reaches the modulo value programmed in the pit counter modulo registers. clear pof by reading the pit status and control register when pof is set and then writing a logic 0 to pof. if another pit overflow occurs before the clearing sequence is complete, then writing logic 0 to pof has no effect. therefore, a pof interrupt request cannot be lost due to inadvertent clearing of pof. reset clears the pof bit. writing a logic 1 to pof has no effect. 1 = pit counter has reached modulo value 0 = pit counter has not reached modulo value poie ? pit overflow interrupt enable bit this read/write bit enables pit overflow interrupts when the pof bit becomes set. reset clears the poie bit. 1 = pit overflow interrupts enabled 0 = pit overflow interrupts disabled pstop ? pit stop bit this read/write bit stops the pit counter. counting resumes when pstop is cleared. reset sets the pstop bit, stopping the pit counter until software clears the pstop bit. 1 = pit counter stopped 0 = pit counter active address: $004b bit 7654321bit 0 read: pof poie pstop 00 pps2 pps1 pps0 write: 0 prst reset:00100000 = unimplemented figure 18-3. pit status and control register (psc) programmable interrupt timer (pit) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola programmable interrupt timer (pit) 289 note: do not set the pstop bit before entering wait mode if the pit is required to exit wait mode. prst ? pit reset bit setting this write-only bit resets the pit counter and the pit prescaler. setting prst has no effect on any other registers. counting resumes from $0000. prst is cleared automatically after the pit counter is reset and always reads as logic zero. reset clears the prst bit. 1 = prescaler and pit counter cleared 0 = no effect note: setting the pstop and prst bits simultaneously stops the pit counter at a value of $0000. pps[2:0] ? prescaler select bits these read/write bits select one of the seven prescaler outputs as the input to the pit counter as table 18-2 shows. reset clears the pps[2:0] bits. table 18-2. prescaler selection pps[2:0] pit clock source 000 internal bus clock 1 001 internal bus clock 2 010 internal bus clock 4 011 internal bus clock 8 100 internal bus clock 16 101 internal bus clock 32 110 internal bus clock 64 111 internal bus clock 64 programmable interrupt timer (pit) technical data MC68HC08AZ32A ? rev 1.0 290 programmable interrupt timer (pit) motorola 18.8.2 pit counter registers the two read-only pit counter registers contain the high and low bytes of the value in the pit counter. reading the high byte (pcnth) latches the contents of the low byte (pcntl) into a buffer. subsequent reads of pcnth do not affect the latched pcntl value until pcntl is read. reset clears the pit counter registers. setting the pit reset bit (prst) also clears the pit counter registers. note: if you read pcnth during a break interrupt, be sure to unlatch pcntl by reading pcntl before exiting the break interrupt. otherwise, pcntl retains the value latched during the break. address: $004c bit 7654321bit 0 read: bit 15 14 13 12 11 10 9 bit 8 write: reset:00000000 address: $004d bit 7654321bit 0 read: bit 15 14 13 12 11 10 9 bit 8 write: reset:00000000 = unimplemented figure 18-4. pit counter registers (pcnth ? pcntl) programmable interrupt timer (pit) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola programmable interrupt timer (pit) 291 18.8.3 pit counter modulo registers the read/write pit modulo registers contain the modulo value for the pit counter. when the pit counter reaches the modulo value the overflow flag (pof) becomes set and the pit counter resumes counting from $0000 at the next timer clock. writing to the high byte (pmodh) inhibits the pof bit and overflow interrupts until the low byte (pmodl) is written. reset sets the pit counter modulo registers. note: reset the pit counter before writing to the pit counter modulo registers. address: $004e:$004f bit 7654321bit 0 read: bit 15 14 13 12 11 10 9 bit 8 write: reset:11111111 address: $004e:$004f bit 7654321bit 0 read: bit 7654321bit 0 write: reset:11111111 figure 18-5. pit counter modulo registers (pmodh ? pmodl) programmable interrupt timer (pit) technical data MC68HC08AZ32A ? rev 1.0 292 programmable interrupt timer (pit) motorola MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 293 technical data ? MC68HC08AZ32A section 19. i/o ports 19.1 contents 19.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294 19.3 port a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 19.3.1 port a data register (pta) . . . . . . . . . . . . . . . . . . . . . . . 295 19.3.2 data direction register a (ddra) . . . . . . . . . . . . . . . . . 296 19.4 port b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 19.4.1 port b data register (ptb) . . . . . . . . . . . . . . . . . . . . . . . 298 19.4.2 data direction register b (ddrb) . . . . . . . . . . . . . . . . . 299 19.5 port c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 19.5.1 port c data register (ptc) . . . . . . . . . . . . . . . . . . . . . . . 301 19.5.2 data direction register c (ddrc) . . . . . . . . . . . . . . . . . 302 19.6 port d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304 19.6.1 port d data register (ptd) . . . . . . . . . . . . . . . . . . . . . . . 304 19.6.2 data direction register d (ddrd) . . . . . . . . . . . . . . . . . 305 19.7 port e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307 19.7.1 port e data register (pte) . . . . . . . . . . . . . . . . . . . . . . . 307 19.7.2 data direction register e (ddre) . . . . . . . . . . . . . . . . . . 310 19.8 port f . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312 19.8.1 port f data register (ptf) . . . . . . . . . . . . . . . . . . . . . . . . 312 19.8.2 data direction register f (ddrf) . . . . . . . . . . . . . . . . . . 313 19.9 port g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315 19.9.1 port g data register (ptg) . . . . . . . . . . . . . . . . . . . . . . . 315 19.9.2 data direction register g (ddrg) . . . . . . . . . . . . . . . . . 316 19.10 port h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318 19.10.1 port h data register (pth) . . . . . . . . . . . . . . . . . . . . . . . 318 19.10.2 data direction register h (ddrh) . . . . . . . . . . . . . . . . . 319 i/o ports technical data MC68HC08AZ32A ? rev 1.0 294 i/o ports motorola 19.2 introduction fifty bidirectional input-output (i/o) pins form eight parallel ports. all i/o pins are programmable as inputs or outputs. note: connect any unused i/o pins to an appropriate logic level, either v dd or v ss . although the i/o ports do not require termination for proper operation, termination reduces excess current consumption and the possibility of electrostatic damage. table 19-1. i/o port register summary register name bit 7654321bit 0addr. port a data register (pta) pta7 pta6 pta5 pta4 pta3 pta2 pta1 pta0 $0000 port b data register (ptb) ptb7 ptb6ptb5ptb4ptb3ptb2ptb1ptb0$0001 port c data register (ptc) r: 0 0 ptc5 ptc4 ptc3 ptc2 ptc1 ptc0 $0002 w: rr port d data register (ptd) ptd7 ptd6 ptd5 ptd4 ptd3 ptd2 ptd1 ptd0 $0003 data direction register a (ddra) ddra7 ddra6 ddra5 ddra4 ddra3 ddra2 ddra1 ddra0 $0004 data direction register b (ddrb) ddrb7 ddrb6 ddrb5 ddrb4 ddrb3 ddrb2 ddrb1 ddrb0 $0005 data direction register c (ddrc) r: mclken 0 ddrc5 ddrc4 ddrc3 ddrc2 ddrc1 ddrc0 $0006 w: r data direction register d (ddrd) ddrd7 ddrd6 ddrd5 ddrd4 ddrd3 ddr2 ddrd1 ddrd0 $0007 port e data register (pte) pte7 pte6pte5pte4pte3pte2pte1pte0$0008 port f data register (ptf) r: 0 ptf6 ptf5 ptf4 ptf3 ptf2 ptf1 ptf0 $0009 w: r port g data register (ptg) r: 0 0 0 0 0 ptg2 ptg1 ptg0 $000a w: r rrrr port h data register (pth) r:0 00000 pth1 pth0 $000b w: r rrrrr data direction register e (ddre) ddre7 ddre6 ddre5 ddre4 ddre3 ddre2 ddre1 ddre0 $000c data direction register f (ddrf) r: 0 ddrf6 ddrf5 ddrf4 ddrf3 ddrf2 ddrf1 ddrf0 $000d w: r i/o ports port a MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 295 19.3 port a port a is an 8-bit general-purpose bidirectional i/o port. 19.3.1 port a data register (pta) the port a data register contains a data latch for each of the eight port a pins. pta[7:0] ? port a data bits these read/write bits are software programmable. data direction of each port a pin is under the control of the corresponding bit in data direction register a. reset has no effect on port a data. data direction register g (ddrg) r: 0 0 0 0 0 ddrg2 ddrg1 ddrg0 $000e w: r rrrr data direction register h (ddrh) r:0 00000 ddrh1 ddrh0 $000f w: r rrrrr r=reserved table 19-1. i/o port register summary (continued) register name bit 7654321bit 0addr. bit 7654321bit 0 pta $0000 read: pta7 pta6 pta5 pta4 pta3 pta2 pta1 pta0 write: reset: unaffected by reset figure 19-1. port a data register (pta) i/o ports technical data MC68HC08AZ32A ? rev 1.0 296 i/o ports motorola 19.3.2 data direction register a (ddra) data direction register a determines whether each port a pin is an input or an output. writing a logic one to a ddra bit enables the output buffer for the corresponding port a pin; a logic zero disables the output buffer. ddra[7:0] ? data direction register a bits these read/write bits control port a data direction. reset clears ddra[7:0], configuring all port a pins as inputs. 1 = corresponding port a pin configured as output 0 = corresponding port a pin configured as input note: avoid glitches on port a pins by writing to the port a data register before changing data direction register a bits from 0 to 1. figure 19-3 shows the port a i/o logic. figure 19-3. port a i/o circuit bit 7654321bit 0 ddra $0004 read: ddra7 ddra6 ddra5 ddra4 ddra3 ddra2 ddra1 ddra0 write: reset:00000000 figure 19-2 data direction register a (ddra) read ddra ($0004) write ddra ($0004) reset write pta ($0000) read pta ($0000) ptax ddrax ptax internal data bus i/o ports port a MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 297 when bit ddrax is a logic one, reading address $0000 reads the ptax data latch. when bit ddrax is a logic zero, reading address $0000 reads the voltage level on the pin. the data latch can always be written, regardless of the state of its data direction bit. table 19-2 summarizes the operation of the port a pins. table 19-2. port a pin functions ddra bit pta bit i/o pin mode accesses to ddra accesses to pta read/write read write 0 x (1) input, hi-z (2) ddra[7:0] pin pta[7:0] (3) 1 x output ddra[7:0] pta[7:0] pta[7:0] 1. x = don ? t care 2. hi-z = high impedance 3. writing affects data register, but does not affect input. i/o ports technical data MC68HC08AZ32A ? rev 1.0 298 i/o ports motorola 19.4 port b port b is an 8-bit special function port that shares all of its pins with the analog to digital convertor. 19.4.1 port b data register (ptb) the port b data register contains a data latch for each of the eight port b pins. ptb[7:0] ? port b data bits these read/write bits are software programmable. data direction of each port b pin is under the control of the corresponding bit in data direction register b. reset has no effect on port b data. atd[7:0] ? adc channels note: ptb7/atd7 ? ptb0/atd0 are eight of the analog to digital converter channels. the adc channel select bits, ch[4:0], determine whether the ptb7/atd7 ? ptb0/atd0 pins are adc channels or general-purpose i/o pins. if an adc channel is selected and a read of this corresponding bit in the port b data register occurs, the data will be zero if the data direction for this bit is programmed as an input. otherwise, the data will reflect the value in the data latch. data direction register b (ddrb) does not affect the data direction of port b pins that are being used by the adc. however, the ddrb bits always determine whether reading port b returns the states of the latches or logic 0. bit 7654321bit 0 ptb $0001 read: ptb7 ptb6 ptb5 ptb4 ptb3 ptb2 ptb1 ptb0 write: reset: unaffected by reset alternate functions atd7 atd6 atd5 atd4 atd3 atd2 atd1 atd0 figure 19-4. port b data register (ptb) i/o ports port b MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 299 19.4.2 data direction register b (ddrb) data direction register b determines whether each port b pin is an input or an output. writing a logic one to a ddrb bit enables the output buffer for the corresponding port b pin; a logic zero disables the output buffer. ddrb[7:0] ? data direction register b bits these read/write bits control port b data direction. reset clears ddrb[7:0], configuring all port b pins as inputs. 1 = corresponding port b pin configured as output 0 = corresponding port b pin configured as input note: avoid glitches on port b pins by writing to the port b data register before changing data direction register b bits from 0 to 1. figure 19-6 shows the port b i/o logic. bit 7654321bit 0 ddrb $0005 read: ddrb7 ddrb6 ddrb5 ddrb4 ddrb3 ddrb2 ddrb1 ddrb0 write: reset:00000000 figure 19-5. data direction register b (ddrb) figure 19-6. port b i/o circuit read ddrb ($0005) write ddrb ($0005) reset write ptb ($0001) read ptb ($0001) ptbx ddrbx ptbx internal data bus i/o ports technical data MC68HC08AZ32A ? rev 1.0 300 i/o ports motorola when bit ddrbx is a logic one, reading address $0001 reads the ptbx data latch. when bit ddrbx is a logic zero, reading address $0001 reads the voltage level on the pin. the data latch can always be written, regardless of the state of its data direction bit. table 19-3 summarizes the operation of the port b pins. table 19-3. port b pin functions ddrb bit ptb bit i/o pin mode accesses to ddrb accesses to ptb read/write read write 0 x (1) input, hi-z (2) ddrb[7:0] pin ptb[7:0] (3) 1 x output ddrb[7:0] ptb[7:0] ptb[7:0] 1. x = don ? t care 2. hi-z = high impedance 3. writing affects data register, but does not affect input. i/o ports port c MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 301 19.5 port c port c is a 6-bit general-purpose bidirectional i/o port. 19.5.1 port c data register (ptc) the port c data register contains a data latch for each of the six port c pins. ptc[5:0] ? port c data bits these read/write bits are software-programmable. data direction of each port c pin is under the control of the corresponding bit in data direction register c. reset has no effect on port c data. mclk ? system clock bit the system clock is driven out of ptc2 when enabled by mclken in ptc ddr7. bit 7654321bit 0 ptc $0002 read: 00 ptc5 ptc4 ptc3 ptc2 ptc1 ptc0 write: r r reset: unaffected by reset alternate functions mclk r=reserved figure 19-7. port c data register (ptc) i/o ports technical data MC68HC08AZ32A ? rev 1.0 302 i/o ports motorola 19.5.2 data direction register c (ddrc) data direction register c determines whether each port c pin is an input or an output. writing a logic one to a ddrc bit enables the output buffer for the corresponding port c pin; a logic zero disables the output buffer. mclken ? mclk enable bit this read/write bit enables mclk to be an output signal on ptc2. if mclk is enabled, ddrc2 has no effect. reset clears this bit. 1 = mclk output enabled 0 = mclk output disabled ddrc[5:0] ? data direction register c bits these read/write bits control port c data direction. reset clears ddrc[7:0], configuring all port c pins as inputs. 1 = corresponding port c pin configured as output 0 = corresponding port c pin configured as input note: avoid glitches on port c pins by writing to the port c data register before changing data direction register c bits from 0 to 1. bit 7654321bit 0 ddrc $0006 read: mclken 0 ddrc5 ddrc4 ddrc3 ddrc2 ddrc1 ddrc0 write: r reset:0 0000000 r=reserved figure 19-8. data direction register c (ddrc) i/o ports port c MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 303 figure 19-9 shows the port c i/o logic. when bit ddrcx is a logic one, reading address $0002 reads the ptcx data latch. when bit ddrcx is a logic zero, reading address $0002 reads the voltage level on the pin. the data latch can always be written, regardless of the state of its data direction bit. table 19-4 summarizes the operation of the port c pins. . figure 19-9. port c i/o circuit read ddrc ($0006) write ddrc ($0006) reset write ptc ($0002) read ptc ($0002) ptcx ddrcx ptcx internal data bus table 19-4. port c pin functions ddrc bit ptc bit i/o pin mode accesses to ddrc accesses to ptc read/write read write 0 2 input, hi-z ddrc[7] pin ptc2 1 2 output ddrc[7] 0 ? 0 x (1) input, hi-z (2) ddrc[5:0] pin ptc[5:0] (3) 1 x output ddrc[5:0] ptc[5:0] ptc[5:0] 1. x = don ? t care 2. hi-z = high impedance 3. writing affects data register, but does not affect input. i/o ports technical data MC68HC08AZ32A ? rev 1.0 304 i/o ports motorola 19.6 port d port d is an 8 -bit special function port that shares seven of it ? s pins with the analog to digital converter and two with the tima and timb modules 19.6.1 port d data register (ptd) the port d data register contains a data latch for each of the eight port d pins. ptd[7:0] ? port d data bits ptd[7:0] are read/write, software programmable bits. data direction of ptd[7:0] pins are under the control of the corresponding bit in data direction register d. atd[14:8] ? adc channel status bits ptd6/atd14/taclk ? ptd0/atd8 are seven of the 15 analog-to-digital converter channels. the atd channel select bits, ch[4:0], determine whether the ptd6/atd14/taclk ? ptd0/atd8 pins are adc channels or general purpose i/o pins. if an adc channel is selected and a read of this corresponding bit in the port b data register occurs, the data will be 0 if the data direction for this bit is programmed as an input. otherwise the data will reflect the value in the data latch. note: data direction register d (ddrd) does not affect the data direction of port d pins that are being used by the tima or timb. however, the ddrd bits always determine whether reading port d returns the states of the latches to logic 0. bit 7654321bit 0 ptd $0003 read: ptd7 ptd6 ptd5 ptd4 ptd3 ptd2 ptd1 ptd0 write: reset: unaffected by reset alternate functions r atd14/ taclk atd13 atd12/ tbclk atd11 atd10 atd9 atd8 figure 19-10. port d data register (ptd) i/o ports port d MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 305 taclk/tbclk ? timer clock input the ptd6/atd14/taclk pin is the external clock input for the tima. the ptd4/tbclk pin is the external clock input for the timb.the prescaler select bits, ps[2:0], select ptd6/atd14/taclk or ptd4/tbclk as the tim clock input (see tima channel status and control registers on page 402 and timb status and control register on page 273). when not selected as the tim clock, ptd6/taclk and ptd4/tbclk are available for general purpose i/o. while taclk/tbclk are selected, corresponding ddrd bits have no effect. 19.6.2 data direction register d (ddrd) data direction register d determines whether each port d pin is an input or an output. writing a logic one to a ddrd bit enables the output buffer for the corresponding port d pin; a logic zero disables the output buffer. ddrd[7:0] ? data direction register d bits these read/write bits control port d data direction. reset clears ddrd[7:0], configuring all port d pins as inputs. 1 = corresponding port d pin configured as output 0 = corresponding port d pin configured as input note: avoid glitches on port d pins by writing to the port d data register before changing data direction register d bits from 0 to 1. figure 19-12 shows the port d i/o logic. when bit ddrdx is a logic one, reading address $0003 reads the ptdx data latch. when bit ddrdx is a logic zero, reading address $0003 reads the voltage level on the pin. the data latch can always be written, bit 7654321bit 0 ddrd $0007 read: ddrd7 ddrd6 ddrd5 ddrd4 ddrd3 ddrd2 ddrd1 ddrd0 write: reset:00000000 figure 19-11. data direction register d (ddrd) i/o ports technical data MC68HC08AZ32A ? rev 1.0 306 i/o ports motorola regardless of the state of its data direction bit. table 19-5 summarizes the operation of the port d pins. figure 19-12. port d i/o circuit read ddrd ($0007) write ddrd ($0007) reset write ptd ($0003) read ptd ($0003) ptdx ddrdx ptdx internal data bus table 19-5. port d pin functions ddrd bit ptd bit i/o pin mode accesses to ddrd accesses to ptd read/write read write 0 x (1) input, hi-z (2) ddrd[7:0] pin ptd[7:0] (3) 1 x output ddrd[7:0] ptd[7:0] ptd[7:0] 1. x = don ? t care 2. hi-z = high impedance 3. writing affects data register, but does not affect input. i/o ports port e MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 307 19.7 port e port e is an 8-bit special function port that shares two of its pins with the timer interface module (tima), two of its pins with the serial communications interface module (sci) and four of its pins with the serial peripheral interface module (spi). 19.7.1 port e data register (pte) the port e data register contains a data latch for each of the eight port e pins. pte[7:0] ? port e data bits pte[7:0] are read/write, software programmable bits. data direction of each port e pin is under the control of the corresponding bit in data direction register e. spsck ? spi serial clock the pte7/spsck pin is the serial clock input of a spi slave module and serial clock output of a spi master modules. when the spe bit is clear, the pte7/spsck pin is available for general-purpose i/o. mosi ? master out/slave in the pte6/mosi pin is the master out/slave in terminal of the spi module. when the spe bit is clear, the pte6/mosi pin is available for general-purpose i/o. see spi control register (spcr) on page 252. bit 7654321bit 0 pte $0008 read: pte7 pte6 pte5 pte4 pte3 pte2 pte1 pte0 write: reset: unaffected by reset alternate function: spsck mosi miso ss tach1 tach0 rxd txd figure 19-13. port e data register (pte) i/o ports technical data MC68HC08AZ32A ? rev 1.0 308 i/o ports motorola miso ? master in/slave out the pte5/miso pin is the master in/slave out terminal of the spi module. when the spi enable bit, spe, is clear, the spi module is disabled, and the pte5/miso pin is available for general-purpose i/o. see spi control register (spcr) on page 252. ss ? slave select the pte4/ss pin is the slave select input of the spi module. when the spe bit is clear, or when the spi master bit, spmstr, is set and modfen bit is low, the pte4/ss pin is available for general-purpose i/o. see spi control register (spcr) on page 252. when the spi is enabled as a slave, the ddrf0 bit in data direction register e (ddre) has no effect on the pte4/ss pin. note: data direction register e (ddre) does not affect the data direction of port e pins that are being used by the spi module. however, the ddre bits always determine whether reading port e returns the states of the latches or the states of the pins. see table 19-6 . tach[1:0] ? timer a channel i/o bits the pte3/tach1 ? pte2/tach0 pins are the tima input capture/output compare pins. the edge/level select bits, elsxb:elsxa, determine whether the pte3/tach1 ? pte2/tach0 pins are timer channel i/o pins or general-purpose i/o pins. see tima channel status and control registers on page 402. note: data direction register e (ddre) does not affect the data direction of port e pins that are being used by the tima. however, the ddre bits always determine whether reading port e returns the states of the latches or the states of the pins. see table 19-6 . i/o ports port e MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 309 rxd ? sci receive data input the pte1/rxd pin is the receive data input for the sci module. when the enable sci bit, ensci, is clear, the sci module is disabled, and the pte1/rxd pin is available for general-purpose i/o. see sci control register 1 on page 209. txd ? sci transmit data output the pte0/txd pin is the transmit data output for the sci module. when the enable sci bit, ensci, is clear, the sci module is disabled, and the pte0/txd pin is available for general-purpose i/o. see sci control register 2 on page 212. note: data direction register e (ddre) does not affect the data direction of port e pins that are being used by the sci module. however, the ddre bits always determine whether reading port e returns the states of the latches or the states of the pins. see table 19-6 . i/o ports technical data MC68HC08AZ32A ? rev 1.0 310 i/o ports motorola 19.7.2 data direction register e (ddre) data direction register e determines whether each port e pin is an input or an output. writing a logic one to a ddre bit enables the output buffer for the corresponding port e pin; a logic zero disables the output buffer. ddre[7:0] ? data direction register e bits these read/write bits control port e data direction. reset clears ddre[7:0], configuring all port e pins as inputs. 1 = corresponding port e pin configured as output 0 = corresponding port e pin configured as input note: avoid glitches on port e pins by writing to the port e data register before changing data direction register e bits from 0 to 1. figure 19-15 shows the port e i/o logic. bit 7654321bit 0 ddre $000c read: ddre7 ddre6 ddre5 ddre4 ddre3 ddre2 ddre1 ddre0 write: reset:00000000 figure 19-14. data direction register e (ddre) figure 19-15. port e i/o circuit read ddre ($000c) write ddre ($000c) reset write pte ($0008) read pte ($0008) ptex ddrex ptex internal data bus i/o ports port e MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 311 when bit ddrex is a logic one, reading address $0008 reads the ptex data latch. when bit ddrex is a logic zero, reading address $0008 reads the voltage level on the pin. the data latch can always be written, regardless of the state of its data direction bit. table 19-6 summarizes the operation of the port e pins. table 19-6. port e pin functions ddre bit pte bit i/o pin mode accesses to ddre accesses to pte read/write read write 0 x (1) input, hi-z (2) ddre[7:0] pin pte[7:0] (3) 1 x output ddre[7:0] pte[7:0] pte[7:0] 1. x = don ? t care 2. hi-z = high impedance 3. writing affects data register, but does not affect input. i/o ports technical data MC68HC08AZ32A ? rev 1.0 312 i/o ports motorola 19.8 port f port f is a 7-bit special function port that shares four of its pins with the timer interface module (tima) and two of its pins with the timer interface module (timb)). 19.8.1 port f data register (ptf) the port f data register contains a data latch for each of the seven port f pins. ptf[6:0] ? port f data bits these read/write bits are software programmable. data direction of each port f pin is under the control of the corresponding bit in data direction register f. reset has no effect on ptf[6:0]. tach[5:2] ? timer a channel i/o bits the ptf3/tach5 ? ptf0/tach2 pins are the tim input capture/output compare pins. the edge/level select bits, elsxb:elsxa, determine whether the ptf3/tach5 ? ptf0/tach2 pins are timer channel i/o pins or general-purpose i/o pins. bit 7654321bit 0 ptf $0009 read: 0 ptf6 ptf5 ptf4 ptf3 ptf2 ptf1 ptf0 write: r reset: unaffected by reset alternate function: tbch1 tbch0 tach5 tach4 tach3 tach2 r= reserved figure 19-16. port f data register (ptf) i/o ports port f MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 313 tbch[1:0] ? timer b channel i/o bits the ptf5/tbch1-ptf4/tbch0 pins are the timb input capture/output compare pins. the edge/level select bits, elsxb:elsxa, determine whether the ptf5/tbch1-ptf4/tbch0 pins are timer channel i/o pins or general purpose i/o pins. see timb status and control register on page 273. note: data direction register f(ddrf) does not affect the data direction of port f pins that are being used by tima and timb. however, the ddrf bits always determine whether reading port f returns the states of the latches or the states of the pins. see table 19-7 . 19.8.2 data direction register f (ddrf) data direction register f determines whether each port f pin is an input or an output. writing a logic one to a ddrf bit enables the output buffer for the corresponding port f pin; a logic zero disables the output buffer. ddrf[6:0] ? data direction register f bits these read/write bits control port f data direction. reset clears ddrf[6:0], configuring all port f pins as inputs. 1 = corresponding port f pin configured as output 0 = corresponding port f pin configured as input note: avoid glitches on port f pins by writing to the port f data register before changing data direction register f bits from 0 to 1. bit 7654321bit 0 ddrf $000d read: 0 ddrf6 ddrf5 ddrf4 ddrf3 ddrf2 ddrf1 ddrf0 write: r reset: 0000000 r= reserved figure 19-17. data direction register f (ddrf) i/o ports technical data MC68HC08AZ32A ? rev 1.0 314 i/o ports motorola figure 19-18 shows the port f i/o logic. when bit ddrfx is a logic one, reading address $0009 reads the ptfx data latch. when bit ddrfx is a logic zero, reading address $0009 reads the voltage level on the pin. the data latch can always be written, regardless of the state of its data direction bit. table 19-7 summarizes the operation of the port f pins. figure 19-18. port f i/o circuit read ddrf ($000d) write ddrf ($000d) reset write ptf ($0009) read ptf ($0009) ptfx ddrfx ptfx internal data bus table 19-7. port f pin functions ddrf bit ptf bit i/o pin mode accesses to ddrf accesses to ptf read/write read write 0 x (1) input, hi-z (2) ddrf[6:0] pin ptf[6:0] (3) 1 x output ddrf[6:0] ptf[6:0] ptf[6:0] 1. x = don ? t care 2. hi-z = high impedance 3. writing affects data register, but does not affect input. i/o ports port g MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 315 19.9 port g port g is a 3-bit special function port that shares all of its pins with the keyboard interrupt module (kbd). 19.9.1 port g data register (ptg) the port g data register contains a data latch for each of the three port g pins. ptg[2:0] ? port g data bits these read/write bits are software-programmable. data direction of each port g pin is under the control of the corresponding bit in data direction register g. reset has no effect on ptg[2:0]. kbd[2:0] ? keyboard wakeup pins the keyboard interrupt enable bits, kbie[2:0], in the keyboard interrupt control register (kbicr), enable the port g pins as external interrupt pins. see keyboard module (kbd) on page 373. enabling an external interrupt pin will override the corresponding ddrgx. bit 7654321bit 0 ptg $000a read: 00000 ptg2 ptg1 ptg0 write:rrrrr reset: unaffected by reset alternate function kbd2 kbd1 kbd0 r= reserved figure 19-19. port g data register (ptg) i/o ports technical data MC68HC08AZ32A ? rev 1.0 316 i/o ports motorola 19.9.2 data direction register g (ddrg) data direction register g determines whether each port g pin is an input or an output. writing a logic one to a ddrg bit enables the output buffer for the corresponding port g pin; a logic zero disables the output buffer. ddrg[2:0] ? data direction register g bits these read/write bits control port g data direction. reset clears ddrg[2:0], configuring all port g pins as inputs. 1 = corresponding port g pin configured as output 0 = corresponding port g pin configured as input note: avoid glitches on port g pins by writing to the port g data register before changing data direction register g bits from 0 to 1. figure 19-21 shows the port g i/o logic. bit 7654321bit 0 ddrg $000e read: 00000 ddrg2 ddrg1 ddrg0 write:rrrrr reset:00000000 r= reserved figure 19-20. data direction register g (ddrg) figure 19-21. port g i/o circuit read ddrg ($000e) write ddrg ($000e) reset write ptg ($000a) read ptg ($000a) ptgx ddrgx ptgx internal data bus i/o ports port g MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 317 when bit ddrgx is a logic one, reading address $000a reads the ptgx data latch. when bit ddrgx is a logic zero, reading address $000a reads the voltage level on the pin. the data latch can always be written, regardless of the state of its data. table 19-8 summarises the operation of the port g pins. table 19-8. port g pin functions ddrg bit ptg bit i/o pin mode accesses to ddrg accesses to ptg read/write read write 0 x (1) input, hi-z (2) ddrg[2:0] pin ptg[2:0] (3) 1 x output ddrg[2:0] ptg[2:0] ptg[2:0] 1. x = don ? t care 2. hi-z = high impedance 3. writing affects data register, but does not affect input. i/o ports technical data MC68HC08AZ32A ? rev 1.0 318 i/o ports motorola 19.10 port h port h is a 2-bit special function port that shares all of its pins with the keyboard interrupt module (kbd). 19.10.1 port h data register (pth) the port h data register contains a data latch for each of the two port h pins. pth[1:0] ? port h data bits these read/write bits are software-programmable. data direction of each port h pin is under the control of the corresponding bit in data direction register h. reset has no effect on port g data. kbd[4:3] ? keyboard wakeup pins the keyboard interrupt enable bits, kbie[4:3], in the keyboard interrupt control register (kbicr), enable the port h pins as external interrupt pins. see keyboard module (kbd) on page 373. bit 7654321bit 0 pth $000b read: 000000 pth1 pth0 write:rrrrrr reset: unaffected by reset alternate function kbd4 kbd3 r= reserved figure 19-22. port h data register (pth) i/o ports port h MC68HC08AZ32A ? rev 1.0 technical data motorola i/o ports 319 19.10.2 data direction register h (ddrh) data direction register h determines whether each port h pin is an input or an output. writing a logic one to a ddrh bit enables the output buffer for the corresponding port h pin; a logic zero disables the output buffer. ddrh[1:0] ? data direction register h bits these read/write bits control port h data direction. reset clears ddrh[1:0], configuring all port h pins as inputs. 1 = corresponding port h pin configured as output 0 = corresponding port h pin configured as input note: avoid glitches on port h pins by writing to the port h data register before changing data direction register h bits from 0 to 1. figure 19-24 shows the port h i/o logic. bit 7654321bit 0 ddrh $000f read: 000000 ddrh1 ddrh0 write:rrrrrr reset:00000000 r= reserved figure 19-23. data direction register h (ddrh) figure 19-24. port h i/o circuit read ddrh ($000e) write ddrh ($000e) reset write pth ($000a) read pth ($000a) ptgx ddrhx pthx internal data bus i/o ports technical data MC68HC08AZ32A ? rev 1.0 320 i/o ports motorola when bit ddrhx is a logic one, reading address $000b reads the pthx data latch. when bit ddrhx is a logic zero, reading address $000b reads the voltage level on the pin. the data latch can always be written, regardless of the state of its data. table 19-9 summarises the operation of the port h pins. table 19-9. port h pin functions ddrh bit pth bit i/o pin mode accesses to ddrh accesses to pth read/write read write 0 x (1) input, hi-z (2) ddrh[1:0] pin pth[1:0] (3) 1 x output ddrh[1:0] pth[1:0] pth[1:0] 1. x = don ? t care 2. hi-z = high impedance 3. writing affects data register, but does not affect input. MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 321 technical data ? MC68HC08AZ32A section 20. mscan08 controller (mscan08) 20.1 contents 20.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322 20.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 20.4 external pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324 20.5 message storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325 20.5.1 background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325 20.5.2 receive structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326 20.5.3 transmit structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329 20.6 identifier acceptance filter . . . . . . . . . . . . . . . . . . . . . . . . . 330 20.7 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335 20.7.1 interrupt acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . . 336 20.7.2 interrupt vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337 20.8 protocol violation protection . . . . . . . . . . . . . . . . . . . . . . . 337 20.9 low power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338 20.9.1 mscan08 sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 339 20.9.2 mscan08 soft reset mode . . . . . . . . . . . . . . . . . . . . . . . 340 20.9.3 mscan08 power down mode . . . . . . . . . . . . . . . . . . . . . 341 20.9.4 cpu wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341 20.9.5 programmable wakeup function . . . . . . . . . . . . . . . . . . 342 20.10 timer link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342 20.11 clock system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342 20.12 memory map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346 20.13 programmer ? s model of message storage . . . . . . . . . . . . . 346 20.13.1 message buffer outline . . . . . . . . . . . . . . . . . . . . . . . . . . 347 20.13.2 identifier registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347 mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 322 mscan08 controller (mscan08) motorola 20.13.3 data length register (dlr) . . . . . . . . . . . . . . . . . . . . . . 351 20.13.4 data segment registers (dsrn) . . . . . . . . . . . . . . . . . . . 351 20.13.5 transmit buffer priority registers . . . . . . . . . . . . . . . . . 352 20.14 programmer ? s model of control registers . . . . . . . . . . . . 352 20.14.1 mscan08 module control register 0 . . . . . . . . . . . . . . 355 20.14.2 mscan08 module control register 1 . . . . . . . . . . . . . . 357 20.14.3 mscan08 bus timing register 0 . . . . . . . . . . . . . . . . . . 358 20.14.4 mscan08 bus timing register 1 . . . . . . . . . . . . . . . . . . 359 20.14.5 mscan08 receiver flag register (crflg) . . . . . . . . . . 361 20.14.6 mscan08 receiver interrupt enable register . . . . . . . 363 20.14.7 mscan08 transmitter flag register . . . . . . . . . . . . . . . 365 20.14.8 mscan08 transmitter control register . . . . . . . . . . . . 366 20.14.9 mscan08 identifier acceptance control register . . . . 367 20.14.10 mscan08 receive error counter . . . . . . . . . . . . . . . . . . 369 20.14.11 mscan08 transmit error counter . . . . . . . . . . . . . . . . . 369 20.14.12 mscan08 identifier acceptance registers . . . . . . . . . . 370 20.14.13 mscan08 identifier mask registers (cidmr0-3) . . . . . 371 20.2 introduction the mscan08 is the specific implementation of the motorola scalable controller area network (mscan) concept targeted for the motorola m68hc08 microcontroller family. the module is a communication controller implementing the can 2.0 a/b protocol as defined in the bosch specification dated september 1991. the can protocol was primarily, but not exclusively, designed to be used as a vehicle serial data bus, meeting the specific requirements of this field: real-time processing, reliable operation in the electromagnetic interference (emi) environment of a vehicle, cost-effectiveness and required bandwidth. mscan08 utilizes an advanced buffer arrangement, resulting in a predictable real-time behavior, and simplifies the application software. mscan08 controller (mscan08) features MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 323 20.3 features basic features of the mscan08 are: modular architecture implementation of the can protocol ? version 2.0a/b ? standard and extended data frames. ? 0 ? 8 bytes data length. ? programmable bit rate up to 1 mbps depending on the actual bit timing and the clock jitter of the pll support for remote frames double-buffered receive storage scheme triple-buffered transmit storage scheme with internal prioritisation using a ? local priority ? concept flexible maskable identifier filter supports alternatively one full size extended identifier filter or two 16-bit filters or four 8-bit filters programmable wakeup functionality with integrated low-pass filter programmable loop-back mode supports self-test operation separate signalling and interrupt capabilities for all can receiver and transmitter error states (warning, error passive, bus off) programmable mscan08 clock source either cpu bus clock or crystal oscillator output programmable link to on-chip timer interface module (timb) for time-stamping and network synchronization low-power sleep mode mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 324 mscan08 controller (mscan08) motorola 20.4 external pins the mscan08 uses two external pins, one input (rxcan) and one output (txcan). the txcan output pin represents the logic level on the can: 0 is for a dominant state, and 1 is for a recessive state. a typical can system with mscan08 is shown in figure 20-1 . figure 20-1. the can system each can station is connected physically to the can bus lines through a transceiver chip. the transceiver is capable of driving the large current needed for the can and has current protection against defective can or defective stations. c a n bus can controller (mscan08) transceiver can node 1 can station 1 can node 2 can node n can_l can_h txcan rxcan mcu mscan08 controller (mscan08) message storage MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 325 20.5 message storage mscan08 facilitates a sophisticated message storage system which addresses the requirements of a broad range of network applications. 20.5.1 background modern application layer software is built under two fundamental assumptions: 1. any can node is able to send out a stream of scheduled messages without releasing the bus between two messages. such nodes will arbitrate for the bus right after sending the previous message and will only release the bus in case of lost arbitration. 2. the internal message queue within any can node is organized as such that the highest priority message will be sent out first if more than one message is ready to be sent. above behaviour cannot be achieved with a single transmit buffer. that buffer must be reloaded right after the previous message has been sent. this loading process lasts a definite amount of time and has to be completed within the inter-frame sequence (ifs) to be able to send an uninterrupted stream of messages. even if this is feasible for limited can bus speeds, it requires that the cpu reacts with short latencies to the transmit interrupt. a double buffer scheme would de-couple the re-loading of the transmit buffers from the actual message being sent and as such reduces the reactiveness requirements on the cpu. problems may arise if the sending of a message would be finished just while the cpu re-loads the second buffer. in that case, no buffer would then be ready for transmission and the bus would be released. at least three transmit buffers are required to meet the first of the above requirements under all circumstances. the mscan08 has three transmit buffers. mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 326 mscan08 controller (mscan08) motorola the second requirement calls for some sort of internal prioritisation which the mscan08 implements with the ? local priority ? concept described in receive structures on page 326. 20.5.2 receive structures the received messages are stored in a 2-stage input first in first out (fifo). the two message buffers are mapped using a ping pong arrangement into a single memory area (see figure 20-2 ). while the background receive buffer (rxbg) is exclusively associated to the mscan08, the foreground receive buffer (rxfg) is addressable by the cpu08. this scheme simplifies the handler software, because only one address area is applicable for the receive process. both buffers have a size of 13 bytes to store the can control bits, the identifier (standard or extended), and the data content (for details, see programmer ? s model of message storage on page 346). the receiver full flag (rxf) in the mscan08 receiver flag register (crflg) (see mscan08 receiver flag register (crflg) on page 361), signals the status of the foreground receive buffer. when the buffer contains a correctly received message with matching identifier, this flag is set. on reception, each message is checked to see if it passes the filter (for details see identifier acceptance filter on page 330) and in parallel is written into rxbg. the mscan08 copies the content of rxbg into rxfg (1) , sets the rxf flag, and generates a receive interrupt to the cpu (2) . the user ? s receive handler has to read the received message from rxfg and to reset the rxf flag to acknowledge the interrupt and to release the foreground buffer. a new message which can follow immediately after the ifs field of the can frame, is received into rxbg. the overwriting of the background buffer is independent of the identifier filter function. 1. only if the rxf flag is not set. 2. the receive interrupt will occur only if not masked. a polling scheme can be applied on rxf also. mscan08 controller (mscan08) message storage MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 327 when the mscan08 module is transmitting, the mscan08 receives its own messages into the background receive buffer, rxbg. it does not overwrite rxfg, generate a receive interrupt or acknowledge its own messages on the can bus. the exception to this rule is in loop-back mode (see mscan08 module control register 1 on page 357), where the mscan08 treats its own messages exactly like all other incoming messages. the mscan08 receives its own transmitted messages in the event that it loses arbitration. if arbitration is lost, the mscan08 must be prepared to become receiver. an overrun condition occurs when both the foreground and the background receive message buffers are filled with correctly received messages with accepted identifiers and another message is correctly received from the bus with an accepted identifier. the latter message will be discarded and an error interrupt with overrun indication will be generated if enabled. the mscan08 is still able to transmit messages with both receive message buffers filled, but all incoming messages are discarded. mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 328 mscan08 controller (mscan08) motorola figure 20-2. user model for message buffer organization rxfg rxbg tx0 rxf txe prio tx1 txe prio tx2 txe prio mscan08 cpu08 ibus mscan08 controller (mscan08) message storage MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 329 20.5.3 transmit structures the mscan08 has a triple transmit buffer scheme to allow multiple messages to be set up in advance and to achieve an optimized real-time performance. the three buffers are arranged as shown in figure 20-2 . all three buffers have a 13-byte data structure similar to the outline of the receive buffers (see programmer ? s model of message storage on page 346). an additional transmit buffer priority register (tbpr) contains an 8-bit ? local priority ? field (prio) (see transmit buffer priority registers on page 352). to transmit a message, the cpu08 has to identify an available transmit buffer which is indicated by a set transmit buffer empty (txe) flag in the mscan08 transmitter flag register (ctflg) (see mscan08 transmitter flag register on page 365). the cpu08 then stores the identifier, the control bits and the data content into one of the transmit buffers. finally, the buffer has to be flagged ready for transmission by clearing the txe flag. the mscan08 then will schedule the message for transmission and will signal the successful transmission of the buffer by setting the txe flag. a transmit interrupt is generated (1) when txe is set and can be used to drive the application software to re-load the buffer. in case more than one buffer is scheduled for transmission when the can bus becomes available for arbitration, the mscan08 uses the local priority setting of the three buffers for prioritisation. for this purpose, every transmit buffer has an 8-bit local priority field (prio). the application software sets this field when the message is set up. the local priority reflects the priority of this particular message relative to the set of messages being emitted from this node. the lowest binary value of the prio field is defined as the highest priority. 1. the transmit interrupt will occur only if not masked. a polling scheme can be applied on txe also. mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 330 mscan08 controller (mscan08) motorola the internal scheduling process takes place whenever the mscan08 arbitrates for the bus. this is also the case after the occurrence of a transmission error. when a high priority message is scheduled by the application software, it may become necessary to abort a lower priority message being set up in one of the three transmit buffers. as messages that are already under transmission cannot be aborted, the user has to request the abort by setting the corresponding abort request flag (abtrq) in the transmission control register (ctcr). the mscan08 will then grant the request, if possible, by setting the corresponding abort request acknowledge (abtak) and the txe flag in order to release the buffer and by generating a transmit interrupt. the transmit interrupt handler software can tell from the setting of the abtak flag whether the message was actually aborted (abtak = 1) or sent (abtak = 0). 20.6 identifier acceptance filter the identifier acceptance registers (cidar0-3) define the acceptance patterns of the standard or extended identifier (id10-id0 or id28-id0). any of these bits can be marked ? don ? t care ? in the identifier mask registers (cidmr0-3). a filter hit is indicated to the application on software by a set rxf (receive buffer full flag, see mscan08 receiver flag register (crflg) on page 361) and two bits in the identifier acceptance control register (see mscan08 identifier acceptance control register on page 367). these identifier hit flags (idhit1-0) clearly identify the filter section that caused the acceptance. they simplify the application software ? s task to identify the cause of the receiver interrupt. in case that more than one hit occurs (two or more filters match) the lower hit has priority. a very flexible programmable generic identifier acceptance filter has been introduced to reduce the cpu interrupt loading. the filter is programmable to operate in four different modes: mscan08 controller (mscan08) identifier acceptance filter MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 331 single identifier acceptance filter, each to be applied to a) the full 29 bits of the extended identifier and to the following bits of the can frame: rtr, ide, srr or b) the 11 bits of the standard identifier plus the rtr and ide bits of can 2.0a/b messages. this mode implements a single filter for a full length can 2.0b compliant extended identifier. figure 20-3 shows how the 32-bit filter bank (cidar0-3, cidmr0-3) produces a filter 0 hit. two identifier acceptance filters, each to be applied to a) the 14 most significant bits of the extended identifier plus the srr and the ide bits of can2.0b messages, or b) the 11 bits of the identifier plus the rtr and ide bits of can 2.0a/b messages. figure 20-4 shows how the 32-bit filter bank (cidar0-3, cidmr0-3) produces filter 0 and 1 hits. four identifier acceptance filters, each to be applied to the first eight bits of the identifier. this mode implements four independent filters for the first eight bits of a can 2.0a/b compliant standard identifier. figure 20-5 shows how the 32-bit filter bank (cidar0- 3, cidmr0-3) produces filter 0 to 3 hits. closed filter. no can message will be copied into the foreground buffer rxfg, and the rxf flag will never be set. figure 20-3. single 32-bit maskable identifier acceptance filter id28 id21 idr0 id10 id3 idr0 id20 id15 idr1 id2 ide idr1 id14 id7 idr2 id10 id3 idr2 id6 rtr idr3 id10 id3 idr3 ac7 ac0 cidar0 am7 am0 cidmr0 ac7 ac0 cidar1 am7 am0 cidmr1 ac7 ac0 cidar2 am7 am0 cidmr2 ac7 ac0 cidar3 am7 am0 cidmr3 id accepted (filter 0 hit) mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 332 mscan08 controller (mscan08) motorola figure 20-4. dual 16-bit maskable acceptance filters id28 id21 idr0 id10 id3 idr0 id20 id15 idr1 id2 ide idr1 id14 id7 idr2 id10 id3 idr2 id6 rtr idr3 id10 id3 idr3 ac7 ac0 cidar0 am7 am0 cidmr0 ac7 ac0 cidar1 am7 am0 cidmr1 id accepted (filter 0 hit) ac7 ac0 cidar2 am7 am0 cidmr2 ac7 ac0 cidar3 am7 am0 cidmr3 id accepted (filter 1 hit) mscan08 controller (mscan08) identifier acceptance filter MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 333 . figure 20-5. quadruple 8-bit maskable acceptance filters ac7 ac0 cidar3 am7 am0 cidmr3 id accepted (filter 3 hit) ac7 ac0 cidar2 am7 am0 cidmr2 id accepted (filter 2 hit) ac7 ac0 cidar1 am7 am0 cidmr1 id accepted (filter 1 hit) id28 id21 idr0 id10 id3 idr0 id20 id15 idr1 id2 ide idr1 id14 id7 idr2 id10 id3 idr2 id6 rtr idr3 id10 id3 idr3 ac7 ac0 cidar0 am7 am0 cidmr0 id accepted (filter 0 hit) mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 334 mscan08 controller (mscan08) motorola 20.6.1 mscan extended id rejected if stuff bit between id16 and id15 for 32-bit and 16-bit identifier acceptance modes, an extended id can frame with a stuff bit between id16 and id15 can be erroneously rejected, depending on idar0, idar1, and idmr1. extended ids (id28-id0) which generate a stuff bit between id16 and id15: where x = 0 or 1 (don ? t care) * = pattern for id28 to id18 (see following). affected extended ids (id28 - id18) patterns: a) xxxxxxxxx01 exceptions: 00000000001 01111100001 xxxx1000001 except 11111000001 b) xxxxx100000 exception: 01111100000 c) xxxx0111111 exception: 00000111111 d) x0111110000 e) 10000000000 f) 11111111111 g) 10000011111 when an affected id is received, an incorrect value is compared to the 2nd byte of the filter (idar1 and idar5, plus idar3 and idar7 in 16- bit mode). this incorrect value is the shift register contents before id15 is shifted in (i.e. right shifted by 1). 20.6.1.1 work- around if the problematic ids cannot be avoided, the workaround is to mask certain bits with idmr1 (and idmr5, plus idmr3 and idmr7 in 16-bit mode). idar0 idar1 idar2 idar3 ******** ***1111x xxxxxxxx xxxxxxxx mscan08 controller (mscan08) interrupts MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 335 example 1: to receive the message ids xxxx xxxx x011 111x xxxx xxxx xxxx xxxx idmr1 etc. must be 111x xxx1, i.e. id20,19,18,15 must be masked. example 2: to receive the message ids xxxx 0111 1111 111x xxxx xxxx xxxx xxxx idmr1 etc. must be 1xxx xxx1, i.e. id20 and id15 must be masked. in general, using idmr1 etc. 1111 xxx1, i.e. masking id20,19,18,srr,15, hides the problem. 20.7 interrupts the mscan08 supports four interrupt vectors mapped onto eleven different interrupt sources, any of which can be individually masked (for details see mscan08 receiver flag register (crflg) on page 361, to mscan08 transmitter control register on page 366). transmit interrupt : at least one of the three transmit buffers is empty (not scheduled) and can be loaded to schedule a message for transmission. the txe flags of the empty message buffers are set. receive interrupt : a message has been received successfully and loaded into the foreground receive buffer. this interrupt will be emitted immediately after receiving the eof symbol. the rxf flag is set. wakeup interrupt : an activity on the can bus occurred during mscan08 internal sleep mode or power-down mode (provided slpak = wupie = 1). error interrupt : an overrun, error, or warning condition occurred. the receiver flag register (crflg) will indicate one of the following conditions: ? overrun: an overrun condition as described in receive structures on page 326, has occurred. ? receiver warning : the receive error counter has reached the cpu warning limit of 96. mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 336 mscan08 controller (mscan08) motorola ? transmitter warning : the transmit error counter has reached the cpu warning limit of 96. ? receiver error passive : the receive error counter has exceeded the error passive limit of 127 and mscan08 has gone to error passive state. ? transmitter error passive : the transmit error counter has exceeded the error passive limit of 127 and mscan08 has gone to error passive state. ? bus off : the transmit error counter has exceeded 255 and mscan08 has gone to bus off state. 20.7.1 interrupt acknowledge interrupts are directly associated with one or more status flags in either the mscan08 receiver flag register (crflg) or the mscan08 transmitter flag register (ctflg). interrupts are pending as long as one of the corresponding flags is set. the flags in the above registers must be reset within the interrupt handler in order to handshake the interrupt. the flags are reset through writing a ? 1 ? to the corresponding bit position. a flag cannot be cleared if the respective condition still prevails. note: bit manipulation instructions ( bset ) shall not be used to clear interrupt flags. mscan08 controller (mscan08) protocol violation protection MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 337 20.7.2 interrupt vectors the mscan08 supports four interrupt vectors as shown in table 20-1 . the vector addresses and the relative interrupt priority are defined in table 2-1 . 20.8 protocol violation protection the mscan08 will protect the user from accidentally violating the can protocol through programming errors. the protection logic implements the following features: the receive and transmit error counters cannot be written or otherwise manipulated. all registers which control the configuration of the mscan08 can not be modified while the mscan08 is on-line. the sftres bit in the mscan08 module control register (see mscan08 module control register 0 on page 355) serves as a lock to protect the following registers: ? mscan08 module control register 1 (cmcr1) ? mscan08 bus timing register 0 and 1 (cbtr0 and cbtr1) ? mscan08 identifier acceptance control register (cidac) ? mscan08 identifier acceptance registers (cidar0 ? 3) table 20-1. mscan08 interrupt vector addresses function source local mask global mask wakeup wupif wupie i bit error interrupts rwrnif rwrnie twrnif twrnie rerrif rerrie terrif terrie boffif boffie ovrif ovrie receive rxf rxfie transmit txe0 txeie0 txe1 txeie1 txe2 txeie2 mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 338 mscan08 controller (mscan08) motorola ? mscan08 identifier mask registers (cidmr0 ? 3) the txcan pin is forced to recessive when the mscan08 is in any of the low power modes. 20.9 low power modes in addition to normal mode, the mscan08 has three modes with reduced power consumption: sleep, soft reset and power down modes. in sleep and soft reset mode, power consumption is reduced by stopping all clocks except those to access the registers. in power down mode, all clocks are stopped and no power is consumed. the wait and stop instructions put the mcu in low power consumption stand-by modes. summarizes the combinations of mscan08 and cpu modes. a particular combination of modes is entered for the given settings of the bits slpak and sftres. for all modes, an mscan wake-up interrupt can occur only if slpak=wupie=1. . table 20-2 mscan08 vs cpu operating modes mscan mode cpu mode stop wait or run power down slpak = x (1) sftres = x 1. ? x ? means don ? t care. sleep slpak = 1 sftres = 0 soft reset slpak = 0 sftres = 1 normal slpak = 0 sftres = 0 mscan08 controller (mscan08) low power modes MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 339 20.9.1 mscan08 sleep mode the cpu can request the mscan08 to enter the low-power mode by asserting the slprq bit in the module configuration register (see figure 20-6 ). the time when the mscan08 enters sleep mode depends on its activity: if it is transmitting, it continues to transmit until there is no more message to be transmitted, and then goes into sleep mode if it is receiving, it waits for the end of this message and then goes into sleep mode if it is neither transmitting or receiving, it will immediately go into sleep mode note: the application software must avoid setting up a transmission (by clearing or more txe flags) and immediately request sleep mode (by setting slprq). it then depends on the exact sequence of operations whether mscan08 starts transmitting or goes into sleep mode directly. during sleep mode, the slpak flag is set. the application software should use slpak as a handshake indication for the request (slprq) to go into sleep mode. when in sleep mode, the mscan08 stops its internal clocks. however, clocks to allow register accesses still run. if the mscan08 is in buss-off state, it stops counting the 128*11 consecutive recessive bits due to the stopped clocks. the txcan pin stays in recessive state. if rxf=1, the message can be read and rxf can be cleared. copying of rxgb into rxfg doesn ? t take place while in sleep mode. it is possible to access the transmit buffers and to clear the txe flags. no message abort takes place while in sleep mode. the mscan08 leaves sleep mode (wake-up) when: bus activity occurs or the mcu clears the slprq bit or the mcu sets the sftres bit mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 340 mscan08 controller (mscan08) motorola figure 20-6. sleep request/acknowledge cycle note: the mcu cannot clear the slprq bit before the mscan08 is in sleep mode (slpak=1). after wake-up, the mscan08 waits for 11 consecutive recessive bits to synchronize to the bus. as a consequence, if the mscan08 is woken- up by a can frame, this frame is not received. the receive message buffers (rxfg and rxbg) contain messages if they were received before sleep mode was entered. all pending actions are executed upon wake-up: copying of rxbg into rxfg, message aborts and message transmissions. if the mscan08 is still in bus-off state after sleep mode was left, it continues counting the 128*11 consecutive recessive bits. 20.9.2 mscan08 soft reset mode in soft reset mode, the mscan08 is stopped. registers can still be accessed. this mode is used to initialize the module configuration, bit timing and the can message filter. see mscan08 module control register 0 on page 355 for a complete description of the soft reset mode. mscan08 running slprq = 0 slpak = 0 sleep request slprq = 1 slpak = 0 mscan08 sleeping slprq = 1 slpak = 1 mcu mscan08 mcu or mscan08 mscan08 controller (mscan08) low power modes MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 341 when setting the sftres bit, the mscan08 immediately stops all ongoing transmissions and receptions, potentially causing can protocol violations. note: the user is responsible to take care that the mscan08 is not active when soft reset mode is entered. the recommended procedure is to bring the mscan08 into sleep mode before the sftres bit is set. 20.9.3 mscan08 power down mode the mscan08 is in power down mode when the cpu is in stop mode. when entering the power down mode, the mscan08 immediately stops all ongoing transmissions and receptions, potentially causing can protocol violations. note: the user is responsible to take care that the mscan08 is not active when power down mode is entered. the recommended procedure is to bring the mscan08 into sleep mode before the stop instruction is executed. to protect the can bus system from fatal consequences of violations to the above rule, the mscan08 drives the txcan pin into recessive state. in power down mode, no registers can be accessed. mscan08 bus activity can wake the mcu from cpu stop/mscan08 power-down mode. however, until the oscillator starts up and synchronisation is achieved the mscan08 will not respond to incoming data. 20.9.4 cpu wait mode the mscan08 module remains active during cpu wait mode. the mscan08 will stay synchronized to the can bus and generates transmit, receive, and error interrupts to the cpu, if enabled. any such interrupt will bring the mcu out of wait mode. mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 342 mscan08 controller (mscan08) motorola 20.9.5 programmable wakeup function the mscan08 can be programmed to apply a low-pass filter function to the rxcan input line while in internal sleep mode (see information on control bit wupm in mscan08 module control register 1 on page 357). this feature can be used to protect the mscan08 from wake-up due to short glitches on the can bus lines. such glitches can result from electromagnetic inference within noisy environments. 20.10 timer link the mscan08 will generate a timer signal whenever a valid frame has been received. because the can specification defines a frame to be valid if no errors occurred before the eof field has been transmitted successfully, the timer signal will be generated right after the eof. a pulse of one bit time is generated. as the mscan08 receiver engine also receives the frames being sent by itself, a timer signal also will be generated after a successful transmission. the previously described timer signal can be routed into the on-chip timer interface module b (timb).this signal is connected to the channel 0 input under the control of the timer link enable (tlnken) bit in the cmcr0. after the timb module has been programmed to capture rising edge events, it can be used under software control to generate 16-bit time stamps which can be stored with the received message. 20.11 clock system figure 20-7 shows the structure of the mscan08 clock generation circuitry and its interaction with the clock generation module (cgm). with this flexible clocking scheme the mscan08 is able to handle can bus rates ranging from 10 kbps up to 1 mbps. mscan08 controller (mscan08) clock system MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 343 figure 20-7. clocking scheme the clock source bit (clksrc) in the mscan08 module control register (cmcr1) (see mscan08 module control register 0 on page 355) defines whether the mscan08 is connected to the output of the crystal oscillator or to the pll output. the clock source has to be chosen such that the tight oscillator tolerance requirements (up to 0.4%) of the can protocol are met. note: if the system clock is generated from a pll, it is recommended to select the crystal clock source rather than the system clock source due to jitter considerations, especially at faster can bus rates. a programmable prescaler is used to generate out of the mscan08 clock the time quanta (tq) clock. a time quantum is the atomic unit of time handled by the mscan08. pll 2 mscan08 prescaler (1 .. 64) osc cgmxclk 2 cgmout (to sim) cgm 2 clksrc mscanclk (2 * bus freq.) bcs mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 344 mscan08 controller (mscan08) motorola a bit time is subdivided into three segments (1) (see figure 20-8 ). sync_seg: this segment has a fixed length of one time quantum. signal edges are expected to happen within this section. time segment 1: this segment includes the prop_seg and the phase_seg1 of the can standard. it can be programmed by setting the parameter tseg1 to consist of 4 to 16 time quanta. time segment 2: this segment represents phase_seg2 of the can standard. it can be programmed by setting the tseg2 parameter to be 2 to 8 time quanta long. the synchronization jump width (sjw) can be programmed in a range of 1 to 4 time quanta by setting the sjw parameter. the above parameters can be set by programming the bus timing registers, cbtr0 ? cbtr1, see mscan08 bus timing register 0 on page 358 and mscan08 bus timing register 1 on page 359). note: it is the user ? s responsibility to make sure that the bit timing settings are in compliance with the can standard, table 20-8 gives an overview on the can conforming segment settings and the related parameter values. 1. for further explanation of the underlying concepts please refer to iso/dis 11 519-1, section 10.3. f tq = f mscanclk presc value bit rate= no. of time quanta f tq mscan08 controller (mscan08) clock system MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 345 figure 20-8. segments within the bit time table 20-3. time segment syntax sync_seg system expects transitions to occur on the bus during this period. transmit point a node in transmit mode will transfer a new value to the can bus at this point. sample point a node in receive mode will sample the bus at this point. if the three samples per bit option is selected then this point marks the position of the third sample. time segment 1 tseg1 time segment 2 tseg2 synchron. jump width sjw 5 .. 10 4 .. 9 2 1 1 .. 2 0 .. 1 4 .. 11 3 .. 10 3 2 1 .. 3 0 .. 2 5 .. 12 4 .. 11 4 3 1 .. 4 0 .. 3 6 .. 13 5 .. 12 5 4 1 .. 4 0 .. 3 7 .. 14 6 .. 13 6 5 1 .. 4 0 .. 3 8 .. 15 7 .. 14 7 6 1 .. 4 0 .. 3 9 .. 16 8 .. 15 8 7 1 .. 4 0 .. 3 table 20-4. can standard compliant bit time segment settings sync _seg time segment 1 time seg. 2 1 4 ... 16 2 ... 8 8... 25 time quanta = 1 bit time nrz signal sample point (single or triple sampling) (prop_seg + phase_seg1) (phase_seg2) mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 346 mscan08 controller (mscan08) motorola 20.12 memory map the mscan08 occupies 128 bytes in the cpu08 memory space, as shown in figure 20-9 . figure 20-9. mscan08 memory map 20.13 programmer ? s model of message storage this section details the organization of the receive and transmit message buffers and the associated control registers. for reasons of programmer interface simplification, the receive and transmit message buffers have the same outline. each message buffer allocates 16 bytes in the memory map containing a 13-byte data structure. an additional transmit buffer priority register (tbpr) is defined for the transmit buffers. $0500 control registers 9 bytes $0508 $0509 reserved 5 bytes $050d $050e error counters 2 bytes $050f $0510 identifier filter 8 bytes $0517 $0518 reserved 40 bytes $053f $0540 receive buffer $054f $0550 transmit buffer 0 $055f $0560 transmit buffer 1 $056f $0570 transmit buffer 2 $057f mscan08 controller (mscan08) programmer ? s model of message storage MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 347 20.13.1 message buffer outline figure 20-11 shows the common 13-byte data structure of receive and transmit buffers for extended identifiers. the mapping of standard identifiers into the idr registers is shown in figure 20-12 . all bits of the 13-byte data structure are undefined out of reset. note: the foreground receive buffer can be read anytime but cannot be written. the transmit buffers can be read or written anytime. addr (1) register name $05b0 identifier register 0 $05b1 identifier register 1 $05b2 identifier register 2 $05b3 identifier register 3 $05b4 data segment register 0 $05b5 data segment register 1 $05b6 data segment register 2 $05b7 data segment register 3 $05b8 data segment register 4 $05b9 data segment register 5 $05ba data segment register 6 $05bb data segment register 7 $05bc data length register $05bd transmit buffer priority register (2) $05be unused $05bf unused 1. where b equals the following: b=4 for receive buffer b=5 for transmit buffer 0 b=6 for transmit buffer 1 b=7 for transmit buffer 2 2. not applicable for receive buffers figure 20-10. message buffer organization mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 348 mscan08 controller (mscan08) motorola 20.13.2 identifier registers the identifiers consist of either 11 bits (id10 ? id0) for the standard, or 29 bits (id28 ? id0) for the extended format. id10/28 is the most significant bit and is transmitted first on the bus during the arbitration procedure. the priority of an identifier is defined to be highest for the smallest binary number. srr ? substitute remote request this fixed recessive bit is used only in extended format. it must be set to 1 by the user for transmission buffers and will be stored as received on the can bus for receive buffers. addrregister bit 7654321bit 0 $05b 0 idr0 read: id28 id27 id26 id25 id24 id23 id22 id21 write: $05b 1 idr1 read: id20 id19 id18 srr (=1) ide (=1) id17 id16 id15 write: $05b 2 idr2 read: id14 id13 id12 id11 id10 id9 id8 id7 write: $05b 3 idr3 read: id6 id5 id4 id3 id2 id1 id0 rtr write: $05b 4dsr0 read: db7 db6 db5 db4 db3 db2 db1 db0 write: $05b 5dsr1 read: db7 db6 db5 db4 db3 db2 db1 db0 write: figure 20-11. receive/transmit message buffer extended identifier (idrn) (sheet 1 of 2) mscan08 controller (mscan08) programmer ? s model of message storage MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 349 $05b 6dsr2 read: db7 db6 db5 db4 db3 db2 db1 db0 write: $05b 7dsr3 read: db7 db6 db5 db4 db3 db2 db1 db0 write: $05b 8dsr4 read: db7 db6 db5 db4 db3 db2 db1 db0 write: $05b 9dsr5 read: db7 db6 db5 db4 db3 db2 db1 db0 write: $05b adsr6 read: db7 db6 db5 db4 db3 db2 db1 db0 write: $05b bdsr7 read: db7 db6 db5 db4 db3 db2 db1 db0 write: $05b cdlr read: dlc3 dlc2 dlc1 dlc0 write: = unimplemented addrregister bit 7654321bit 0 figure 20-11. receive/transmit message buffer extended identifier (idrn) (sheet 2 of 2) mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 350 mscan08 controller (mscan08) motorola ide ? id extended this flag indicates whether the extended or standard identifier format is applied in this buffer. in case of a receive buffer, the flag is set as being received and indicates to the cpu how to process the buffer identifier registers. in case of a transmit buffer, the flag indicates to the mscan08 what type of identifier to send. 1 = extended format, 29 bits 0 = standard format, 11 bits rtr ? remote transmission request this flag reflects the status of the remote transmission request bit in the can frame. in case of a receive buffer, it indicates the status of the received frame and supports the transmission of an answering frame in software. in case of a transmit buffer, this flag defines the setting of the rtr bit to be sent. 1 = remote frame 0 = data frame addr register bit 7 6 5 4 3 2 1 bit 0 $05b 0 idr0 read: id10 id9 id8 id7 id6 id5 id4 id3 write: $05b 1 idr1 read: id2 id1 id0 rtr ide(=0) write: $05b 2 idr2 read: write: $05b 3 idr3 read: write: = unimplemented figure 20-12. standard identifier mapping mscan08 controller (mscan08) programmer ? s model of message storage MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 351 20.13.3 data length register (dlr) this register keeps the data length field of the can frame. dlc3 ? dlc0 ? data length code bits the data length code contains the number of bytes (data byte count) of the respective message. at transmission of a remote frame, the data length code is transmitted as programmed while the number of transmitted bytes is always 0. the data byte count ranges from 0 to 8 for a data frame. table 20-5 shows the effect of setting the dlc bits. 20.13.4 data segment registers (dsrn) the eight data segment registers contain the data to be transmitted or received. the number of bytes to be transmitted or being received is determined by the data length code in the corresponding dlr. table 20-5. data length codes data length code data byte count dlc3 dlc2 dlc1 dlc0 00000 00011 00102 00113 01004 01015 01106 01117 10008 mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 352 mscan08 controller (mscan08) motorola 20.13.5 transmit buffer priority registers prio7 ? prio0 ? local priority this field defines the local priority of the associated message buffer. the local priority is used for the internal prioritisation process of the mscan08 and is defined to be highest for the smallest binary number. the mscan08 implements the following internal prioritisation mechanism: all transmission buffers with a cleared txe flag participate in the prioritisation right before the sof is sent. the transmission buffer with the lowest local priority field wins the prioritisation. in case more than one buffer has the same lowest priority, the message buffer with the lower index number wins. 20.14 programmer ? s model of control registers the programmer ? s model has been laid out for maximum simplicity and efficiency. figure 20-14 gives an overview on the control register block of the mscan08. address: $05bd bit 7654321bit 0 read: prio7 prio6 prio5 prio4 prio3 prio2 prio1 prio0 write: reset:uuuuuuuu figure 20-13. transmit buffer priority register (tbpr) mscan08 controller (mscan08) programmer ? s model of control registers MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 353 addrregister bit 7654321bit 0 $0500 cmcr0 read: 0 0 0 synch tlnken slpak slprq sftres write: $0501 cmcr1 read: 0 0 0 0 0 loopb wupm clksrc write: $0502 cbtr0 read: sjw1 sjw0 brp5 brp4 brp3 brp2 brp1 brp0 write: $0503 cbtr1 read: samp tseg22 tseg21 tseg20 tseg13 tseg12 tseg11 tseg10 write: $0504 crflg read: wupif rwrnif twrnif rerrif terrif boffif ovrif rxf write: $0505 crier read: wupie rwrnie twrnie rerrie terrie boffie ovrie rxfie write: $0506 ctflg read: 0 abtak2 abtak1 abtak0 0 txe2 txe1 txe0 write: $0507 ctcr read: 0 abtrq2 abtrq1 abtrq0 0 txeie2 txeie1 txeie0 write: $0508 cidac read: 0 0 idam1 idam0 0 0 idhit1 idhit0 write: $0509 reserved read: rrrrrrrr write: = unimplemented r = reserved figure 20-14. mscan08 control register structure mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 354 mscan08 controller (mscan08) motorola $050e crxerr read: rxerr7 rxerr6 rxerr5 rxerr4 rxerr3 rxerr2 rxerr1 rxerr0 write: $050f ctxerr read: txerr7 txerr6 txerr5 txerr4 txerr3 txerr2 txerr1 txerr0 write: $0510 cidar0 read: ac7ac6ac5ac4ac3ac2ac1ac0 write: $0511 cidar1 read: ac7ac6ac5ac4ac3ac2ac1ac0 write: $0512 cidar2 read: ac7ac6ac5ac4ac3ac2ac1ac0 write: $0513 cidar3 read: ac7ac6ac5ac4ac3ac2ac1ac0 write: $0514 cidmr0 read: am7am6am5am4am3am2am1am0 write: $0515 cidmr1 read: am7am6am5am4am3am2am1am0 write: $0516 cidmr2 read: am7am6am5am4am3am2am1am0 write: $0517 cidmr3 read: am7am6am5am4am3am2am1am0 write: addrregister bit 7654321bit 0 figure 20-14. mscan08 control register structure (continued) mscan08 controller (mscan08) programmer ? s model of control registers MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 355 20.14.1 mscan08 module control register 0 synch ? synchronized status this bit indicates whether the mscan08 is synchronized to the can bus and as such can participate in the communication process. 1 = mscan08 synchronized to the can bus 0 = mscan08 not synchronized to the can bus tlnken ? timer enable this flag is used to establish a link between the mscan08 and the on-chip timer (see timer link on page 342). 1 = the mscan08 timer signal output is connected to the timer interface module b channel 0. 0 = the port is connected to the timer input. slpak ? sleep mode acknowledge this flag indicates whether the mscan08 is in module internal sleep mode. it shall be used as a handshake for the sleep mode request (see mscan08 sleep mode on page 339). if the mscan08 detects bus activity while in sleep mode, it clears the flag. 1 = sleep ? mscan08 in internal sleep mode 0 = wakeup ? mscan08 is not in sleep mode address: $0500 bit 7654321bit 0 read: 0 0 0 synch tlnken slpak slprq sftres write: reset:00000001 = unimplemented figure 20-15. module control register 0 (cmcr0) mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 356 mscan08 controller (mscan08) motorola slprq ? sleep request, go to internal sleep mode this flag requests the mscan08 to go into an internal power-saving mode (see mscan08 sleep mode on page 339). 1 = sleep ? the mscan08 will go into internal sleep mode. 0 = wakeup ? the mscan08 will function normally. sftres ? soft reset when this bit is set by the cpu, the mscan08 immediately enters the soft reset state. any ongoing transmission or reception is aborted and synchronization to the bus is lost. the following registers enter and stay in their hard reset state: cmcr0, crflg, crier, ctflg, and ctcr. the registers cmcr1, cbtr0, cbtr1, cidac, cidar0 ? 3, and cidmr0 ? 3 can only be written by the cpu when the mscan08 is in soft reset state. the values of the error counters are not affected by soft reset. when this bit is cleared by the cpu, the mscan08 tries to synchronize to the can bus. if the mscan08 is not in bus-off state, it will be synchronized after 11 recessive bits on the bus; if the mscan08 is in bus-off state, it continues to wait for 128 occurrences of 11 recessive bits. clearing sftres and writing to other bits in cmcr0 must be in separate instructions. 1 = mscan08 in soft reset state 0 = normal operation mscan08 controller (mscan08) programmer ? s model of control registers MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 357 20.14.2 mscan08 module control register 1 loopb ? loop back self-test mode when this bit is set, the mscan08 performs an internal loop back which can be used for self-test operation: the bit stream output of the transmitter is fed back to the receiver internally. the rxcan input pin is ignored and the txcan output goes to the recessive state (logic ? 1 ? ). the mscan08 behaves as it does normally when transmitting and treats its own transmitted message as a message received from a remote node. in this state the mscan08 ignores the bit sent during the ack slot of the can frame acknowledge field to insure proper reception of its own message. both transmit and receive interrupt are generated. 1 = activate loop back self-test mode 0 = normal operation wupm ? wakeup mode this flag defines whether the integrated low-pass filter is applied to protect the mscan08 from spurious wakeups (see programmable wakeup function on page 342). 1 = mscan08 will wake up the cpu only in cases of a dominant pulse on the bus which has a length of at least t wup . 0 = mscan08 will wake up the cpu after any recessive to dominant edge on the can bus. address: $0501 bit 7654321bit 0 read: 00000 loopb wupm clksrc write: reset:00000000 = unimplemented figure 20-16. module control register (cmcr1) mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 358 mscan08 controller (mscan08) motorola clksrc ? clock source this flag defines which clock source the mscan08 module is driven from (see clock system on page 342). 1 = the mscan08 clock source is cgmout (see figure 20-7 ). 0 = the mscan08 clock source is cgmxclk/2 (see figure 20-7 ). note: the cmcr1 register can be written only if the sftres bit in the mscan08 module control register is set 20.14.3 mscan08 bus timing register 0 sjw1 and sjw0 ? synchronization jump width the synchronization jump width (sjw) defines the maximum number of time quanta (t q ) clock cycles by which a bit may be shortened, or lengthened, to achieve resynchronization on data transitions on the bus (see table 20-6 ). address: $0502 bit 7654321bit 0 read: sjw1 sjw0 brp5 brp4 brp3 brp2 brp1 brp0 write: reset:00000000 figure 20-17. bus timing register 0 (cbtr0) table 20-6. synchronization jump width sjw1 sjw0 synchronization jump width 00 1 t q cycle 01 2 t q cycle 10 3 t q cycle 11 4 t q cycle mscan08 controller (mscan08) programmer ? s model of control registers MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 359 brp5 ? brp0 ? baud rate prescaler these bits determine the time quanta (t q ) clock, which is used to build up the individual bit timing, according to table 20-7 . note: the cbtr0 register can be written only if the sftres bit in the mscan08 module control register is set. 20.14.4 mscan08 bus timing register 1 samp ? sampling this bit determines the number of serial bus samples to be taken per bit time. if set, three samples per bit are taken, the regular one (sample point) and two preceding samples, using a majority rule. for higher bit rates, samp should be cleared, which means that only one sample will be taken per bit. 1 = three samples per bit (1) 0 = one sample per bit table 20-7. baud rate prescaler brp5 brp4 brp3 brp2 brp1 brp0 prescaler value (p) 000000 1 000001 2 000010 3 000011 4 :::::: : :::::: : 111111 64 address: $0503 bit 7654321bit 0 read: samp tseg22 tseg21 tseg20 tseg13 tseg12 tseg11 tseg10 write: reset:00000000 figure 20-18. bus timing register 1 (cbtr1) 1. in this case phase_seg1 must be at least 2 time quanta. mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 360 mscan08 controller (mscan08) motorola tseg22 ? tseg10 ? time segment time segments within the bit time fix the number of clock cycles per bit time and the location of the sample point. time segment 1 (tseg1) and time segment 2 (tseg2) are programmable as shown in table 20-9 . the bit time is determined by the oscillator frequency, the baud rate prescaler, and the number of time quanta (t q ) clock cycles per bit as shown in table 20-9 ). note: the cbtr1 register can only be written if the sftres bit in the mscan08 module control register is set. table 20-8. time segment values tseg13 tseg12 tseg11 tseg10 time segment 1 tseg22 tseg21 tseg20 time segment 2 0000 1 t q cycle (1) 000 1 t q cycle (1) 0001 2 t q cycles (1) 001 2 t q cycles 0010 3t q cycles (1) ... . 0011 4 t q cycles ... . . ... . 111 8t q cycles . ... . 1111 16 t q cycles 1. this setting is not valid. please refer to table 20-4 for valid settings. bit time= pres value f mscanclk number of time quanta mscan08 controller (mscan08) programmer ? s model of control registers MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 361 20.14.5 mscan08 receiver flag register (crflg) all bits of this register are read and clear only. a flag can be cleared by writing a 1 to the corresponding bit position. a flag can be cleared only when the condition which caused the setting is valid no more. writing a 0 has no effect on the flag setting. every flag has an associated interrupt enable flag in the crier register. a hard or soft reset will clear the register. wupif ? wakeup interrupt flag if the mscan08 detects bus activity while in sleep mode, it sets the wupif flag. if not masked, a wake-up interrupt is pending while this flag is set. 1 = mscan08 has detected activity on the bus and requested wake-up. 0 = no wake-up interrupt has occurred. rwrnif ? receiver warning interrupt flag this flag is set when the mscan08 goes into warning status due to the receive error counter (rec) exceeding 96 and neither one of the error interrupt flags or the bus-off interrupt flag is set (1) . if not masked, an error interrupt is pending while this flag is set. 1 = mscan08 has gone into receiver warning status. 0 = no receiver warning status has been reached. address: $0504 bit 7654321bit 0 read: wupif rwrnif twrnif rerrif terrif boffif ovrif rxf write: reset:00000000 figure 20-19. receiver flag register (crflg) 1. condition to set the flag: rwrnif = (96 e rec) & rerrif & terrif & boffif mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 362 mscan08 controller (mscan08) motorola twrnif ? transmitter warning interrupt flag this flag is set when the mscan08 goes into warning status due to the transmit error counter (tec) exceeding 96 and neither one of the error interrupt flags or the bus-off interrupt flag is set (1) . if not masked, an error interrupt is pending while this flag is set. 1 = mscan08 has gone into transmitter warning status. 0 = no transmitter warning status has been reached. rerrif ? receiver error passive interrupt flag this flag is set when the mscan08 goes into error passive status due to the receive error counter exceeding 127 and the bus-off interrupt flag is not set (2) . if not masked, an error interrupt is pending while this flag is set. 1 = mscan08 has gone into receiver error passive status. 0 = no receiver error passive status has been reached. terrif ? transmitter error passive interrupt flag this flag is set when the mscan08 goes into error passive status due to the transmit error counter exceeding 127 and the bus-off interrupt flag is not set (3) . if not masked, an error interrupt is pending while this flag is set. 1 = mscan08 went into transmit error passive status. 0 = no transmit error passive status has been reached. boffif ? bus-off interrupt flag this flag is set when the mscan08 goes into bus-off status, due to the transmit error counter exceeding 255. it cannot be cleared before the mscan08 has monitored 128 times 11 consecutive ? recessive ? bits on the bus. if not masked, an error interrupt is pending while this flag is set. 1 = mscan08has gone into bus-off status. 0 = no bus-off status has bee reached. 1. condition to set the flag: twrnif = (96 e tec) & rerrif & terrif & boffif 2. condition to set the flag: rerrif = (127 e rec e 255) & boffif 3. condition to set the flag: terrif = (128 e tec e 255) & boffif mscan08 controller (mscan08) programmer ? s model of control registers MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 363 ovrif ? overrun interrupt flag this flag is set when a data overrun condition occurs. if not masked, an error interrupt is pending while this flag is set. 1 = a data overrun has been detected since last clearing the flag. 0 = no data overrun has occurred. rxf ? receive buffer full the rxf flag is set by the mscan08 when a new message is available in the foreground receive buffer. this flag indicates whether the buffer is loaded with a correctly received message. after the cpu has read that message from the receive buffer the rxf flag must be cleared to release the buffer. a set rxf flag prohibits the exchange of the background receive buffer into the foreground buffer. if not masked, a receive interrupt is pending while this flag is set. 1 = the receive buffer is full. a new message is available. 0 = the receive buffer is released (not full). note: to ensure data integrity, no registers of the receive buffer shall be read while the rxf flag is cleared. note: the crflg register is held in the reset state when the sftres bit in cmcr0 is set. 20.14.6 mscan08 receiver interrupt enable register wupie ? wakeup interrupt enable 1 = a wakeup event will result in a wakeup interrupt. 0 = no interrupt will be generated from this event. address: $0505 bit 7654321bit 0 read: wupie rwrnie twrnie rerrie terrie boffie ovrie rxfie write: reset:00000000 figure 20-20. receiver interrupt enable register (crier) mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 364 mscan08 controller (mscan08) motorola rwrnie ? receiver warning interrupt enable 1 = a receiver warning status event will result in an error interrupt. 0 = no interrupt is generated from this event. twrnie ? transmitter warning interrupt enable 1 = a transmitter warning status event will result in an error interrupt. 0 = no interrupt is generated from this event. rerrie ? receiver error passive interrupt enable 1 = a receiver error passive status event will result in an error interrupt. 0 = no interrupt is generated from this event. terrie ? transmitter error passive interrupt enable 1 = a transmitter error passive status event will result in an error interrupt. 0 = no interrupt is generated from this event. boffie ? bus-off interrupt enable 1 = a bus-off event will result in an error interrupt. 0 = no interrupt is generated from this event. ovrie ? overrun interrupt enable 1 = an overrun event will result in an error interrupt. 0 = no interrupt is generated from this event. rxfie ? receiver full interrupt enable 1 = a receive buffer full (successful message reception) event will result in a receive interrupt. 0 = no interrupt will be generated from this event. note: the crier register is held in the reset state when the sftres bit in cmcr0 is set. mscan08 controller (mscan08) programmer ? s model of control registers MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 365 20.14.7 mscan08 transmitter flag register the abort acknowledge flags are read only. the transmitter buffer empty flags are read and clear only. a flag can be cleared by writing a 1 to the corresponding bit position. writing a 0 has no effect on the flag setting. the transmitter buffer empty flags each have an associated interrupt enable bit in the ctcr register. a hard or soft reset will resets the register. abtak2 ? abtak0 ? abort acknowledge this flag acknowledges that a message has been aborted due to a pending abort request from the cpu. after a particular message buffer has been flagged empty, this flag can be used by the application software to identify whether the message has been aborted successfully or has been sent. the abtakx flag is cleared implicitly whenever the corresponding txe flag is cleared. 1 = the message has been aborted. 0 = the message has not been aborted, thus has been sent out. txe2 ? txe0 ? transmitter empty this flag indicates that the associated transmit message buffer is empty, thus not scheduled for transmission. the cpu must handshake (clear) the flag after a message has been set up in the transmit buffer and is due for transmission. the mscan08 sets the flag after the message has been sent successfully. the flag is also set by the mscan08 when the transmission request was successfully address: $0506 5 bit 7654321bit 0 read: 0 abtak2 abtak1 abtak0 0 txe2 txe1 txe0 write: reset:00000111 = unimplemented figure 20-21. transmitter flag register (ctflg) mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 366 mscan08 controller (mscan08) motorola aborted due to a pending abort request (see transmit buffer priority registers on page 352). if not masked, a receive interrupt is pending while this flag is set. clearing a txex flag also clears the corresponding abtakx flag (abtak, see above). when a txex flag is set, the corresponding abtrqx bit (abtrq, see mscan08 transmitter control register ) is cleared. 1 = the associated message buffer is empty (not scheduled). 0 = the associated message buffer is full (loaded with a message due for transmission). note: to ensure data integrity, no registers of the transmit buffers should be written to while the associated txe flag is cleared. note: the ctflg register is held in the reset state when the sftres bit in cmcr0 is set. 20.14.8 mscan08 transmitter control register abtrq2 ? abtrq0 ? abort request the cpu sets an abtrqx bit to request that an already scheduled message buffer (txe = 0) be aborted. the mscan08 will grant the request if the message has not already started transmission, or if the transmission is not successful (lost arbitration or error). when a message is aborted the associated txe and the abort acknowledge flag (abtak) (see mscan08 transmitter flag register on page address: $0507 bit 7654321bit 0 read: 0 abtrq2 abtrq1 abtrq0 0 txeie2 txeie1 txeie0 write: reset:00000000 = unimplemented figure 20-22. transmitter control register (ctcr) mscan08 controller (mscan08) programmer ? s model of control registers MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 367 365) will be set and an txe interrupt is generated if enabled. the cpu cannot reset abtrqx. abtrqx is cleared implicitly whenever the associated txe flag is set. 1 = abort request pending 0 = no abort request note: the software must not clear one or more of the txe flags in ctflg and simultaneously set the respective abtrq bit(s). txeie2 ? txeie0 ? transmitter empty interrupt enable 1 = a transmitter empty (transmit buffer available for transmission) event results in a transmitter empty interrupt. 0 = no interrupt is generated from this event. note: the ctcr register is held in the reset state when the sftres bit in cmcr0 is set. 20.14.9 mscan08 identifier acceptance control register idam1 ? idam0 ? identifier acceptance mode the cpu sets these flags to define the identifier acceptance filter organization (see identifier acceptance filter on page 330). table 20-9 summarizes the different settings. in ? filter closed ? mode no messages will be accepted so that the foreground buffer will never be reloaded. address: $0508 bit 7654321bit 0 read: 0 0 idam1 idam0 0 0 idhit1 idhit0 write: reset:00000000 = unimplemented figure 20-23. identifier acceptance control register (cidac) mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 368 mscan08 controller (mscan08) motorola idhit1 ? idhit0 ? identifier acceptance hit indicator the mscan08 sets these flags to indicate an identifier acceptance hit (see identifier acceptance filter on page 330). table 20-9 summarizes the different settings. the idhit indicators are always related to the message in the foreground buffer. when a message gets copied from the background to the foreground buffer, the indicators are updated as well. note: the cidac register can be written only if the sftres bit in the cmcr0 is set. table 20-9. identifier acceptance mode settings idam1 idam0 identifier acceptance mode 0 0 single 32-bit acceptance filter 0 1 two 16-bit acceptance filter 1 0 four 8-bit acceptance filters 1 1 filter closed table 20-10. identifier acceptance hit indication idhit1 idhit0 identifier acceptance hit 0 0 filter 0 hit 0 1 filter 1 hit 1 0 filter 2 hit 1 1 filter 3 hit mscan08 controller (mscan08) programmer ? s model of control registers MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 369 20.14.10 mscan08 receive error counter this register reflects the status of the mscan08 receive error counter. the register is read only. 20.14.11 mscan08 transmit error counter this register reflects the status of the mscan08 transmit error counter. the register is read only. note: both error counters may only be read when in sleep or soft reset mode. address: $050e bit 7654321bit 0 read: rxerr7 rxerr6 rxerr5 rxerr4 rxerr3 rxerr2 rxerr1 rxerr0 write: reset:00000000 = unimplemented figure 20-24. receiver error counter (crxerr) address: $050f bit 7654321bit 0 read: txerr7 txerr6 txerr5 txerr4 txerr3 txerr2 txerr1 txerr0 write: reset:00000000 = unimplemented figure 20-25. transmit error counter (ctxerr) mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 370 mscan08 controller (mscan08) motorola 20.14.12 mscan08 identifier acceptance registers on reception each message is written into the background receive buffer. the cpu is only signalled to read the message, however, if it passes the criteria in the identifier acceptance and identifier mask registers (accepted); otherwise, the message will be overwritten by the next message (dropped). the acceptance registers of the mscan08 are applied on the idr0 to idr3 registers of incoming messages in a bit by bit manner. for extended identifiers, all four acceptance and mask registers are applied. for standard identifiers only the first two (cidmr0/1 and cidar0/1) are applied. cidar0 address: $0510 bit 7654321bit 0 read: ac7 ac6 ac5 ac4 ac3 ac2 ac1 ac0 write: reset: unaffected by reset cidar1 address: $0511 bit 7654321bit 0 read: ac7 ac6 ac5 ac4 ac3 ac2 ac1 ac0 write: reset: unaffected by reset cidar2 address: $0512 bit 7654321bit 0 read: ac7 ac6 ac5 ac4 ac3 ac2 ac1 ac0 write: reset: unaffected by reset cidar3 address: $0513 bit 7654321bit 0 read: ac7 ac6 ac5 ac4 ac3 ac2 ac1 ac0 write: reset: unaffected by reset figure 20-26. identifier acceptance registers (cidar0 ? cidar3) mscan08 controller (mscan08) programmer ? s model of control registers MC68HC08AZ32A ? rev 1.0 technical data motorola mscan08 controller (mscan08) 371 ac7 ? ac0 ? acceptance code bits ac7 ? ac0 comprise a user-defined sequence of bits with which the corresponding bits of the related identifier register (idrn) of the receive message buffer are compared. the result of this comparison is then masked with the corresponding identifier mask register. note: the cidar0 ? 3 registers can be written only if the sftres bit in cmcr0 is set 20.14.13 mscan08 identifier mask registers (cidmr0-3) the identifier mask registers specify which of the corresponding bits in the identifier acceptance register are relevant for acceptance filtering. for standard identifiers it is required to program the last three bits (am2- am0) in the mask register cidmr1 to ? don ? t care ? . cidmro address: $0514 bit 7654321bit 0 read: am7 am6 am5 am4 am3 am2 am1 am0 write: reset: unaffected by reset cidmr1 address: $0515 bit 7654321bit 0 read: am7 am6 am5 am4 am3 am2 am1 am0 write: reset: unaffected by reset cidmr2 address: $0516 bit 7654321bit 0 read: am7 am6 am5 am4 am3 am2 am1 am0 write: reset: unaffected by reset cidmr3 address: $0517 bit 7654321bit 0 read: am7 am6 am5 am4 am3 am2 am1 am0 write: reset: unaffected by reset figure 20-27. identifier mask registers (cidmr0 ? cidmr3) mscan08 controller (mscan08) technical data MC68HC08AZ32A ? rev 1.0 372 mscan08 controller (mscan08) motorola am7 ? am0 ? acceptance mask bits if a particular bit in this register is cleared, this indicates that the corresponding bit in the identifier acceptance register must be the same as its identifier bit before a match will be detected. the message will be accepted if all such bits match. if a bit is set, it indicates that the state of the corresponding bit in the identifier acceptance register will not affect whether or not the message is accepted. 1 = ignore corresponding acceptance code register bit. 0 = match corresponding acceptance code register and identifier bits. note: the cidmr0-3 registers can be written only if the sftres bit in the cmcr0 is set MC68HC08AZ32A ? rev 1.0 technical data motorola keyboard module (kbd) 373 technical data ? MC68HC08AZ32A section 21. keyboard module (kbd) 21.1 contents 21.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373 21.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 21.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 21.5 keyboard initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377 21.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 21.6.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 21.6.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 21.7 keyboard module during break interrupts . . . . . . . . . . . . 378 21.8 i/o registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379 21.8.1 keyboard status and control register . . . . . . . . . . . . . 379 21.8.2 keyboard interrupt enable register . . . . . . . . . . . . . . . . 380 21.2 introduction the keyboard interrupt module (kbd) provides five independently maskable external interrupt pins. keyboard module (kbd) technical data MC68HC08AZ32A ? rev 1.0 374 keyboard module (kbd) motorola 21.3 features kbd features include: five keyboard interrupt pins with separate keyboard interrupt enable bits and one keyboard interrupt mask hysteresis buffers programmable edge-only or edge- and level- interrupt sensitivity automatic interrupt acknowledge exit from low-power modes 21.4 functional description writing to the kbie4 ? kbie0 bits in the keyboard interrupt enable register independently enables or disables each port g or port h pin as a keyboard interrupt pin. enabling a keyboard interrupt pin also enables its internal pullup device. a logic 0 applied to an enabled keyboard interrupt pin latches a keyboard interrupt request. a keyboard interrupt is latched when one or more keyboard pins goes low after all were high. the modek bit in the keyboard status and control register controls the triggering mode of the keyboard interrupt. if the keyboard interrupt is edge-sensitive only, a falling edge on a keyboard pin does not latch an interrupt request if another keyboard pin is already low. to prevent losing an interrupt request on one pin because another pin is still low, software can disable the latter pin while it is low. if the keyboard interrupt is falling edge- and low level-sensitive, an interrupt request is present as long as any keyboard pin is low. MC68HC08AZ32A ? rev 1.0 technical data motorola keyboard module (kbd) 375 keyboard module (kbd) functional description figure 21-1. keyboard module block diagram register name bit 7654321bit 0 keyboard status and control reg- ister (kbscr) read: 0000keyf0 imaskk modek write: ackk reset:00000000 keyboard interrupt enable regis- ter (kbier) read: 0 0 0 kbie4 kbie3 kbie2 kbie1 kbie0 write: reset:00000000 = unimplemented figure 21-2. i/o register summary table 21-1. i/o register address summary register kbscr kbier address $001b $0021 kb0ie kb4ie . . . keyboard interrupt dq ck clr v dd modek imaskk keyboard interrupt ff request vector fetch decoder ackk internal bus reset to pullup enable kbd4 kbd0 to pullup enable synchronizer keyf keyboard module (kbd) technical data MC68HC08AZ32A ? rev 1.0 376 keyboard module (kbd) motorola if the modek bit is set, the keyboard interrupt pins are both falling edge- and low level-sensitive, and both of the following actions must occur to clear a keyboard interrupt request: vector fetch or software clear ? a vector fetch generates an interrupt acknowledge signal to clear the interrupt request. software may generate the interrupt acknowledge signal by writing a logic 1 to the ackk bit in the keyboard status and control register (kbscr). the ackk bit is useful in applications that poll the keyboard interrupt pins and require software to clear the keyboard interrupt request. writing to the ackk bit prior to leaving an interrupt service routine also can prevent spurious interrupts due to noise. setting ackk does not affect subsequent transitions on the keyboard interrupt pins. a falling edge that occurs after writing to the ackk bit latches another interrupt request. if the keyboard interrupt mask bit, imaskk, is clear, the cpu loads the program counter with the vector address at locations $ffde and $ffdf. return of all enabled keyboard interrupt pins to logic 1. as long as any enabled keyboard interrupt pin is at logic 0, the keyboard interrupt remains set. the vector fetch or software clear and the return of all enabled keyboard interrupt pins to logic 1 may occur in any order. if the modek bit is clear, the keyboard interrupt pin is falling edge- sensitive only. with modek clear, a vector fetch or software clear immediately clears the keyboard interrupt request. reset clears the keyboard interrupt request and the modek bit, clearing the interrupt request even if a keyboard interrupt pin stays at logic 0. the keyboard flag bit (keyf) in the keyboard status and control register can be used to see if a pending interrupt exists. the keyf bit is not affected by the keyboard interrupt mask bit (imaskk) which makes it useful in applications where polling is preferred. to determine the logic level on a keyboard interrupt pin, use the data direction register to configure the pin as an input and read the data register. keyboard module (kbd) keyboard initialization MC68HC08AZ32A ? rev 1.0 technical data motorola keyboard module (kbd) 377 note: setting a keyboard interrupt enable bit (kbiex) forces the corresponding keyboard interrupt pin to be an input, overriding the data direction register. however, the data direction register bit must be a logic 0 for software to read the pin. 21.5 keyboard initialization when a keyboard interrupt pin is enabled, it takes time for the internal pullup to reach a logic 1. therefore, a false interrupt can occur as soon as the pin is enabled. to prevent a false interrupt on keyboard initialization: 1. mask keyboard interrupts by setting the imaskk bit in the keyboard status and control register 2. enable the kbi pins by setting the appropriate kbiex bits in the keyboard interrupt enable register 3. write to the ackk bit in the keyboard status and control register to clear any false interrupts 4. clear the imaskk bit. an interrupt signal on an edge-triggered pin can be acknowledged immediately after enabling the pin. an interrupt signal on an edge- and level-triggered interrupt pin must be acknowledged after a delay that depends on the external load. another way to avoid a false interrupt: 1. configure the keyboard pins as outputs by setting the appropriate ddrg bits in data direction register g. 2. configure the keyboard pins as outputs by setting the appropriate ddrh bits in data direction register h. 3. write logic 1s to the appropriate port g and port h data register bits. 4. enable the kbi pins by setting the appropriate kbiex bits in the keyboard interrupt enable register. keyboard module (kbd) technical data MC68HC08AZ32A ? rev 1.0 378 keyboard module (kbd) motorola 21.6 low-power modes the wait and stop instructions put the mcu in low-power- consumption standby modes. 21.6.1 wait mode the keyboard module remains active in wait mode. clearing the imaskk bit in the keyboard status and control register enables keyboard interrupt requests to bring the mcu out of wait mode. 21.6.2 stop mode the keyboard module remains active in stop mode. clearing the imaskk bit in the keyboard status and control register enables keyboard interrupt requests to bring the mcu out of stop mode. 21.7 keyboard module during break interrupts the bcfe bit in the break flag control register (bfcr) enables software to clear status bits during the break state. see break module on page 149. to allow software to clear the keyf bit during a break interrupt, write a logic 1 to the bcfe bit. if keyf is cleared during the break state, it remains cleared when the mcu exits the break state. to protect the keyf bit during the break state, write a logic 0 to the bcfe bit. with bcfe at logic 0, writing to the keyboard acknowledge bit (ackk) in the keyboard status and control register during the break state has no effect. see keyboard status and control register on page 379. keyboard module (kbd) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola keyboard module (kbd) 379 21.8 i/o registers the following registers control and monitor operation of the keyboard module: keyboard status and control register (kbscr) keyboard interrupt enable register (kbier) 21.8.1 keyboard status and control register the keyboard status and control register: flags keyboard interrupt requests acknowledges keyboard interrupt requests masks keyboard interrupt requests controls keyboard interrupt triggering sensitivity bits 7 ? 4 ? not used these read-only bits always read as logic 0s. keyf ? keyboard flag bit this read-only bit is set when a keyboard interrupt is pending. reset clears the keyf bit. 1 = keyboard interrupt pending 0 = no keyboard interrupt pending address: $001b bit 7654321bit 0 read: 0000keyf0 imaskk modek write: ackk reset:00000000 = unimplemented figure 21-3. keyboard status and control register (kbscr) keyboard module (kbd) technical data MC68HC08AZ32A ? rev 1.0 380 keyboard module (kbd) motorola ackk ? keyboard acknowledge bit writing a logic 1 to this write-only bit clears the keyboard interrupt request. ackk always reads as logic 0. reset clears ackk. imaskk ? keyboard interrupt mask bit writing a logic 1 to this read/write bit prevents the output of the keyboard interrupt mask from generating interrupt requests. reset clears the imaskk bit. 1 = keyboard interrupt requests masked 0 = keyboard interrupt requests not masked modek ? keyboard triggering sensitivity bit this read/write bit controls the triggering sensitivity of the keyboard interrupt pins. reset clears modek. 1 = keyboard interrupt requests on falling edges and low levels 0 = keyboard interrupt requests on falling edges only 21.8.2 keyboard interrupt enable register the keyboard interrupt enable register enables or disables each port g and each port h pin to operate as a keyboard interrupt pin. kbie4 ? kbie0 ? keyboard interrupt enable bits each of these read/write bits enables the corresponding keyboard interrupt pin to latch interrupt requests. reset clears the keyboard interrupt enable register. 1 = port pin enabled as keyboard interrupt pin 0 = port pin not enabled as keyboard interrupt pin address: $0021 bit 7654321bit 0 read: 0 0 0 kbie4 kbie3 kbie2 kbie1 kbie0 write: reset:00000000 = unimplemented figure 21-4. keyboard interrupt enable register (kbier) MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 381 technical data ? MC68HC08AZ32A section 22. timer interface module a (tima) 22.1 contents 22.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382 22.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382 22.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385 22.4.1 tima counter prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . 386 22.4.2 input capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386 22.4.3 output compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387 22.4.3.1 unbuffered output compare . . . . . . . . . . . . . . . . . . . . 387 22.4.3.2 buffered output compare . . . . . . . . . . . . . . . . . . . . . . 388 22.4.4 pulse width modulation (pwm) . . . . . . . . . . . . . . . . . . . 390 22.4.4.1 unbuffered pwm signal generation . . . . . . . . . . . . . 391 22.4.4.2 buffered pwm signal generation . . . . . . . . . . . . . . . . 392 22.4.4.3 pwm initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393 22.5 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395 22.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395 22.6.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395 22.6.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395 22.7 tima during break interrupts . . . . . . . . . . . . . . . . . . . . . . . 396 22.8 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396 22.8.1 tima clock pin (ptd6/atd14/taclk) . . . . . . . . . . . . . . 396 22.8.2 tima channel i/o pins (ptf3/tach5 ? ptf0/tach2 and pte3/tach1 ? pte2/tach0) . . . . . . . . . . . . . . . . . . . . . . 397 22.9 i/o registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397 22.9.1 tima status and control register . . . . . . . . . . . . . . . . . 398 22.9.2 tima counter registers . . . . . . . . . . . . . . . . . . . . . . . . . 400 22.9.3 tima counter modulo registers . . . . . . . . . . . . . . . . . . . 401 22.9.4 tima channel status and control registers . . . . . . . . . 402 22.9.5 tima channel registers . . . . . . . . . . . . . . . . . . . . . . . . . 407 timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 382 timer interface module a (tima) motorola 22.2 introduction this section describes the timer interface module (tima). the tima is a 6-channel timer that provides a timing reference with input capture, output compare and pulse-width-modulation functions. figure 22-1 is a block diagram of the tima. for further information regarding timers on m68hc08 family devices, please consult the hc08 timer reference manual, tim08rm/ad. 22.3 features features of the tima include: six input capture/output compare channels ? rising-edge, falling-edge or any-edge input capture trigger ? set, clear or toggle output compare action buffered and unbuffered pulse width modulation (pwm) signal generation programmable tima clock input ? 7 frequency internal bus clock prescaler selection ? external tima clock input (4 mhz maximum frequency) free-running or modulo up-count operation toggle any channel pin on overflow tima counter stop and reset bits timer interface module a (tima) features MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 383 figure 22-1. tima block diagram prescaler prescaler select tclk internal 16-bit comparator ps2 ps1 ps0 16-bit comparator 16-bit latch tch0h:tch0l ms0a els0b els0a pte2 tof toie inter- channel 0 tmodh:tmodl trst tstop tov0 ch0ie ch0f ch0max ms0b 16-bit counter bus clock ptd6/atd14/taclk pte2/tach0 pte3/tach1 ptf0/tach2 ptf1/tach3 logic rupt logic inter- rupt logic 16-bit comparator 16-bit latch tch1h:tch1l ms1a els1b els1a pte3 channel 1 tov1 ch1ie ch1f ch1max logic inter- rupt logic 16-bit comparator 16-bit latch tch2h:tch2l ms2a els2b els2a ptf0 channel 2 tov2 ch2ie ch2f ch2max ms2b logic inter- rupt logic 16-bit comparator 16-bit latch tch3h:tch3l ms3a els3b els3a ptf1 channel 3 tov3 ch3ie ch3f ch3max logic inter- rupt logic 16-bit comparator 16-bit latch tch4h:tch4l ms4a els4b els4a ptf2 channel 4 tov4 ch4ie ch4f ch5max ms4b logic inter- rupt logic 16-bit comparator 16-bit latch tch5h:tch5l ms5a els5b els5a ptf3 channel 5 tov5 ch5ie ch5f ch5max logic inter- rupt logic ptf2/tach4/tach ptf3/tach5/tach timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 384 timer interface module a (tima) motorola figure 22-2. tima i/o register summary addr. register name bit 7 6 5 4 3 2 1 bit 0 $0020 tima status/control register (tasc) r: tof toie tstop 00 ps2 ps1 ps0 w: 0 trst r $0022 tima counter register high (tacnth) r: bit 15 14 13 12 11 10 9 bit 8 w:rrrrrrrr $0023 tima counter register low (tacntl) r:bit 7654321bit 0 w:rrrrrrrr $0024 tima counter modulo reg. high (tamodh) r: bit 15 14 13 12 11 10 9 bit 8 w: $0025 tima counter modulo reg. low (tamodl) r: bit 7654321bit 0 w: $0026 tima ch. 0 status/control register (tasc0) r: ch0f ch0ie ms0b ms0a els0b els0a tov0 ch0max w: 0 $0027 tima ch. 0 register high (tach0h) r: bit 15 14 13 12 11 10 9 bit 8 w: $0028 tima ch. 0 register low (tach0l) r: bit 7654321bit 0 w: $0029 tima ch. 1 status/control register (tasc1) r: ch1f ch1ie 0 ms1a els1b els1a tov1 ch1max w: 0 r $002a tima ch. 1 register high (tach1h) r: bit 15 14 13 12 11 10 9 bit 8 w: $002b tima ch. 1 register low (tach1l) r: bit 7654321bit 0 w: $002c tima ch. 2 status/control register (tasc2) r: ch2f ch2ie ms2b ms2a els2b els2a tov2 ch2max w: 0 $002d tima ch. 2 register high (tach2h) r: bit 15 14 13 12 11 10 9 bit 8 w: $002e tima ch. 2 register low (tach2l) r: bit 7654321bit 0 w: $002f tima ch. 3 status/control register (tasc3) r: ch3f ch3ie 0 ms3a els3b els3a tov3 ch3max w: 0 r $0030 tima ch. 3 register high (tach3h) r: bit 15 14 13 12 11 10 9 bit 8 w: $0031 tima ch. 3 register low (tach3l) r: bit 7654321bit 0 w: timer interface module a (tima) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 385 22.4 functional description figure 22-1 shows the tima structure. the central component of the tima is the 16-bit tima counter that can operate as a free-running counter or a modulo up-counter. the tima counter provides the timing reference for the input capture and output compare functions. the tima counter modulo registers, tamodh ? tamodl, control the modulo value of the tima counter. software can read the tima counter value at any time without affecting the counting sequence. the six tima channels are programmable independently as input capture or output compare channels. $0032 tima ch. 4 status/control register (tasc4) r: ch4f ch4ie ms4b ms4a els4b els4a tov4 ch4max w: 0 $0033 tima ch. 4 register high (tach4h) r: bit 15 14 13 12 11 10 9 bit 8 w: $0034 tima ch. 4 register low (tach4l) r: bit 7654321bit 0 w: $0035 tima ch. 5 status/control register (tasc5) r: ch5f ch5ie 0 ms5a els5b els5a tov5 ch5max w: 0 r $0036 tima ch. 5 register high (tach5h) r: bit 15 14 13 12 11 10 9 bit 8 w: $0037 tima ch. 5 register low (tach5l) r: bit 7654321bit 0 w: r= reserved figure 22-2. tima i/o register summary addr. register name bit 7 6 5 4 3 2 1 bit 0 timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 386 timer interface module a (tima) motorola 22.4.1 tima counter prescaler the tima clock source can be one of the seven prescaler outputs or the tima clock pin, ptd6/atd14/taclk. the prescaler generates seven clock rates from the internal bus clock. the prescaler select bits, ps[2:0], in the tima status and control register select the tima clock source. 22.4.2 input capture an input capture function has three basic parts: edge select logic, an input capture latch and a 16-bit counter. two 8-bit registers, which make up the 16-bit input capture register, are used to latch the value of the free-running counter after the corresponding input capture edge detector senses a defined transition. the polarity of the active edge is programmable. the level transition which triggers the counter transfer is defined by the corresponding input edge bits (elsxb and elsxa in tasc0 through tasc5 control registers with x referring to the active channel number). when an active edge occurs on the pin of an input capture channel, the tima latches the contents of the tima counter into the tima channel registers, tachxh ? tachxl. input captures can generate tima cpu interrupt requests. software can determine that an input capture event has occurred by enabling input capture interrupts or by polling the status flag bit. the free-running counter contents are transferred to the tima channel register (tachxh ? tachxl see tima channel registers on page 407) on each proper signal transition regardless of whether the tima channel flag (ch0f ? ch5f in tasc0 ? tasc5 registers) is set or clear. when the status flag is set, a cpu interrupt is generated if enabled. the value of the count latched or ? captured ? is the time of the event. because this value is stored in the input capture register 2 bus cycles after the actual event occurs, user software can respond to this event at a later time and determine the actual time of the event. however, this must be done prior to another input capture on the same pin; otherwise, the previous time value will be lost. by recording the times for successive edges on an incoming signal, software can determine the period and/or pulse width of the signal. to measure a period, two successive edges of the same polarity are timer interface module a (tima) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 387 captured. to measure a pulse width, two alternate polarity edges are captured. software should track the overflows at the 16-bit module counter to extend its range. another use for the input capture function is to establish a time reference. in this case, an input capture function is used in conjunction with an output compare function. for example, to activate an output signal a specified number of clock cycles after detecting an input event (edge), use the input capture function to record the time at which the edge occurred. a number corresponding to the desired delay is added to this captured value and stored to an output compare register (see tima channel registers on page 407). because both input captures and output compares are referenced to the same 16-bit modulo counter, the delay can be controlled to the resolution of the counter independent of software latencies. reset does not affect the contents of the tima channel register (tachxh ? tachxl). 22.4.3 output compare with the output compare function, the tima can generate a periodic pulse with a programmable polarity, duration and frequency. when the counter reaches the value in the registers of an output compare channel, the tima can set, clear or toggle the channel pin. output compares can generate tima cpu interrupt requests. 22.4.3.1 unbuffered output compare any output compare channel can generate unbuffered output compare pulses as described in output compare on page 387. the pulses are unbuffered because changing the output compare value requires writing the new value over the old value currently in the tima channel registers. an unsynchronized write to the tima channel registers to change an output compare value could cause incorrect operation for up to two counter overflow periods. for example, writing a new value before the counter reaches the old value but after the counter reaches the new value prevents any compare during that counter overflow period. also, timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 388 timer interface module a (tima) motorola using a tima overflow interrupt routine to write a new, smaller output compare value may cause the compare to be missed. the tima may pass the new value before it is written. use the following methods to synchronize unbuffered changes in the output compare value on channel x: when changing to a smaller value, enable channel x output compare interrupts and write the new value in the output compare interrupt routine. the output compare interrupt occurs at the end of the current output compare pulse. the interrupt routine has until the end of the counter overflow period to write the new value. when changing to a larger output compare value, enable tima overflow interrupts and write the new value in the tima overflow interrupt routine. the tima overflow interrupt occurs at the end of the current counter overflow period. writing a larger value in an output compare interrupt routine (at the end of the current pulse) could cause two output compares to occur in the same counter overflow period. 22.4.3.2 buffered output compare channels 0 and 1 can be linked to form a buffered output compare channel whose output appears on the pte2/tach0 pin. the tima channel registers of the linked pair alternately control the output. setting the ms0b bit in tima channel 0 status and control register (tasc0) links channel 0 and channel 1. the output compare value in the tima channel 0 registers initially controls the output on the pte2/tach0 pin. writing to the tima channel 1 registers enables the tima channel 1 registers to synchronously control the output after the tima overflows. at each subsequent overflow, the tima channel registers (0 or 1) that control the output are the ones written to last. tasc0 controls and monitors the buffered output compare function and tima channel 1 status and control register (tasc1) is unused. while the ms0b bit is set, the channel 1 pin, pte3/tach1, is available as a general-purpose i/o pin. timer interface module a (tima) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 389 channels 2 and 3 can be linked to form a buffered output compare channel whose output appears on the ptf0/tach2 pin. the tima channel registers of the linked pair alternately control the output. setting the ms2b bit in tima channel 2 status and control register (tasc2) links channel 2 and channel 3. the output compare value in the tima channel 2 registers initially controls the output on the ptf0/tach2 pin. writing to the tima channel 3 registers enables the tima channel 3 registers to synchronously control the output after the tima overflows. at each subsequent overflow, the tima channel registers (2 or 3) that control the output are the ones written to last. tasc2 controls and monitors the buffered output compare function, and tima channel 3 status and control register (tasc3) is unused. while the ms2b bit is set, the channel 3 pin, ptf1/tach3, is available as a general-purpose i/o pin. channels 4 and 5 can be linked to form a buffered output compare channel whose output appears on the ptf2/tach4 pin. the tima channel registers of the linked pair alternately control the output. setting the ms4b bit in tima channel 4 status and control register (tasc4) links channel 4 and channel 5. the output compare value in the tima channel 4 registers initially controls the output on the ptf2/tach4 pin. writing to the tima channel 5 registers enables the tima channel 5 registers to synchronously control the output after the tima overflows. at each subsequent overflow, the tima channel registers (4 or 5) that control the output are the ones written to last. tasc4 controls and monitors the buffered output compare function and tima channel 5 status and control register (tasc5) is unused. while the ms4b bit is set, the channel 5 pin, ptf3/tach5, is available as a general-purpose i/o pin. note: in buffered output compare operation, do not write new output compare values to the currently active channel registers. user software should track the currently active channel to prevent writing a new value to the active channel. writing to the active channel registers is the same as generating unbuffered output compares. timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 390 timer interface module a (tima) motorola 22.4.4 pulse width modulation (pwm) by using the toggle-on-overflow feature with an output compare channel, the tima can generate a pwm signal. the value in the tima counter modulo registers determines the period of the pwm signal. the channel pin toggles when the counter reaches the value in the tima counter modulo registers. the time between overflows is the period of the pwm signal. as figure 22-3 shows, the output compare value in the tima channel registers determines the pulse width of the pwm signal. the time between overflow and output compare is the pulse width. program the tima to clear the channel pin on output compare if the state of the pwm pulse is logic 1. program the tima to set the pin if the state of the pwm pulse is logic 0. figure 22-3. pwm period and pulse width the value in the tima counter modulo registers and the selected prescaler output determines the frequency of the pwm output. the frequency of an 8-bit pwm signal is variable in 256 increments. writing $00ff (255) to the tima counter modulo registers produces a pwm period of 256 times the internal bus clock period if the prescaler select value is $000 (see tima status and control register on page 398). the value in the tima channel registers determines the pulse width of the pwm output. the pulse width of an 8-bit pwm signal is variable in 256 increments. writing $0080 (128) to the tima channel registers produces a duty cycle of 128/256 or 50%. ptex/tchx period pulse width overflow overflow overflow output compare output compare output compare timer interface module a (tima) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 391 22.4.4.1 unbuffered pwm signal generation any output compare channel can generate unbuffered pwm pulses as described in pulse width modulation (pwm) on page 390. the pulses are unbuffered because changing the pulse width requires writing the new pulse width value over the value currently in the tima channel registers. an unsynchronized write to the tima channel registers to change a pulse width value could cause incorrect operation for up to two pwm periods. for example, writing a new value before the counter reaches the old value but after the counter reaches the new value prevents any compare during that pwm period. also, using a tima overflow interrupt routine to write a new, smaller pulse width value may cause the compare to be missed. the tima may pass the new value before it is written to the tima channel registers. use the following methods to synchronize unbuffered changes in the pwm pulse width on channel x: when changing to a shorter pulse width, enable channel x output compare interrupts and write the new value in the output compare interrupt routine. the output compare interrupt occurs at the end of the current pulse. the interrupt routine has until the end of the pwm period to write the new value. when changing to a longer pulse width, enable tima overflow interrupts and write the new value in the tima overflow interrupt routine. the tima overflow interrupt occurs at the end of the current pwm period. writing a larger value in an output compare interrupt routine (at the end of the current pulse) could cause two output compares to occur in the same pwm period. note: in pwm signal generation, do not program the pwm channel to toggle on output compare. toggling on output compare prevents reliable 0% duty cycle generation and removes the ability of the channel to self- correct in the event of software error or noise. toggling on output compare also can cause incorrect pwm signal generation when changing the pwm pulse width to a new, much larger value. timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 392 timer interface module a (tima) motorola 22.4.4.2 buffered pwm signal generation channels 0 and 1 can be linked to form a buffered pwm channel whose output appears on the pte2/tach0 pin. the tima channel registers of the linked pair alternately control the pulse width of the output. setting the ms0b bit in tima channel 0 status and control register (tasc0) links channel 0 and channel 1. the tima channel 0 registers initially control the pulse width on the pte2/tach0 pin. writing to the tima channel 1 registers enables the tima channel 1 registers to synchronously control the pulse width at the beginning of the next pwm period. at each subsequent overflow, the tima channel registers (0 or 1) that control the pulse width are the ones written to last. tasc0 controls and monitors the buffered pwm function and tima channel 1 status and control register (tasc1) is unused. while the ms0b bit is set, the channel 1 pin, pte3/tach1, is available as a general-purpose i/o pin. channels 2 and 3 can be linked to form a buffered pwm channel whose output appears on the ptf0/tach2 pin. the tima channel registers of the linked pair alternately control the pulse width of the output. setting the ms2b bit in tima channel 2 status and control register (tasc2) links channel 2 and channel 3. the tima channel 2 registers initially control the pulse width on the ptf0/tach2 pin. writing to the tima channel 3 registers enables the tima channel 3 registers to synchronously control the pulse width at the beginning of the next pwm period. at each subsequent overflow, the tima channel registers (2 or 3) that control the pulse width are the ones written to last. tasc2 controls and monitors the buffered pwm function and tima channel 3 status and control register (tasc3) is unused. while the ms2b bit is set, the channel 3 pin, ptf1/tach3, is available as a general-purpose i/o pin. channels 4 and 5 can be linked to form a buffered pwm channel whose output appears on the ptf2/tach4 pin. the tima channel registers of the linked pair alternately control the pulse width of the output. setting the ms4b bit in tima channel 4 status and control register (tasc4) links channel 4 and channel 5. the tima channel 4 registers timer interface module a (tima) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 393 initially control the pulse width on the ptf2/tach4 pin. writing to the tima channel 5 registers enables the tima channel 5 registers to synchronously control the pulse width at the beginning of the next pwm period. at each subsequent overflow, the tima channel registers (4 or 5) that control the pulse width are the ones written to last. tasc4 controls and monitors the buffered pwm function and tima channel 5 status and control register (tasc5) is unused. while the ms4b bit is set, the channel 5 pin, ptf3/tach5, is available as a general-purpose i/o pin. note: in buffered pwm signal generation, do not write new pulse width values to the currently active channel registers. user software should track the currently active channel to prevent writing a new value to the active channel. writing to the active channel registers is the same as generating unbuffered pwm signals. 22.4.4.3 pwm initialization to ensure correct operation when generating unbuffered or buffered pwm signals, use the following initialization procedure: 1. in the tima status and control register (tasc): a. stop the tima counter and prescaler by setting the tima stop bit, tstop. b. reset the tima counter and prescaler by setting the tima reset bit, trst. 2. in the tima counter modulo registers (tamodh ? tamodl) write the value for the required pwm period. 3. in the tima channel x registers (tachxh ? tachxl) write the value for the required pulse width. 4. in tima channel x status and control register (tascx): a. write 0:1 (for unbuffered output compare or pwm signals) or 1:0 (for buffered output compare or pwm signals) to the mode select bits, msxb ? msxa (see table 22-2 ). b. write 1 to the toggle-on-overflow bit, tovx. timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 394 timer interface module a (tima) motorola c. write 1:0 (to clear output on compare) or 1:1 (to set output on compare) to the edge/level select bits, elsxb ? elsxa. the output action on compare must force the output to the complement of the pulse width level (see table 22-2 ). note: in pwm signal generation, do not program the pwm channel to toggle on output compare. toggling on output compare prevents reliable 0% duty cycle generation and removes the ability of the channel to self- correct in the event of software error or noise. toggling on output compare can also cause incorrect pwm signal generation when changing the pwm pulse width to a new, much larger value. 5. in the tima status control register (tasc) clear the tima stop bit, tstop. setting ms0b links channels 0 and 1 and configures them for buffered pwm operation. the tima channel 0 registers (tach0h ? tach0l) initially control the buffered pwm output. tima status control register 0 (tasc0) controls and monitors the pwm signal from the linked channels. ms0b takes priority over ms0a. setting ms2b links channels 2 and 3 and configures them for buffered pwm operation. the tima channel 2 registers (tach2h ? tach2l) initially control the buffered pwm output. tima status control register 2 (tasc2) controls and monitors the pwm signal from the linked channels. ms2b takes priority over ms2a. setting ms4b links channels 4 and 5 and configures them for buffered pwm operation. the tima channel 4 registers (tach4h ? tach4l) initially control the buffered pwm output. tima status control register 4 (tasc4) controls and monitors the pwm signal from the linked channels. ms4b takes priority over ms4a. clearing the toggle-on-overflow bit, tovx, inhibits output toggles on tima overflows. subsequent output compares try to force the output to a state it is already in and have no effect. the result is a 0% duty cycle output. setting the channel x maximum duty cycle bit (chxmax) and setting the tovx bit generates a 100% duty cycle output (see tima channel status and control registers on page 402). timer interface module a (tima) interrupts MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 395 22.5 interrupts the following tima sources can generate interrupt requests: tima overflow flag (tof) ? the tof bit is set when the tima counter reaches the modulo value programmed in the tima counter modulo registers. the tima overflow interrupt enable bit, toie, enables tima overflow cpu interrupt requests. tof and toie are in the tima status and control register. tima channel flags (ch5f ? ch0f) ? the chxf bit is set when an input capture or output compare occurs on channel x. channel x tima cpu interrupt requests are controlled by the channel x interrupt enable bit, chxie. 22.6 low-power modes the wait and stop instructions put the mcu in low power- consumption standby modes. 22.6.1 wait mode the tima remains active after the execution of a wait instruction. in wait mode, the tima registers are not accessible by the cpu. any enabled cpu interrupt request from the tima can bring the mcu out of wait mode. if tima functions are not required during wait mode, reduce power consumption by stopping the tima before executing the wait instruction. 22.6.2 stop mode the tima is inactive after the execution of a stop instruction. the stop instruction does not affect register conditions or the state of the tima counter. tima operation resumes when the mcu exits stop mode. timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 396 timer interface module a (tima) motorola 22.7 tima during break interrupts a break interrupt stops the tima counter and inhibits input captures. the system integration module (sim) controls whether status bits in other modules can be cleared during the break state. the bcfe bit in the sim break flag control register (sbfcr) enables software to clear status bits during the break state (see sim break flag control register (sbfcr) on page 115). to allow software to clear status bits during a break interrupt, write a logic 1 to the bcfe bit. if a status bit is cleared during the break state, it remains cleared when the mcu exits the break state. to protect status bits during the break state, write a logic 0 to the bcfe bit. with bcfe at logic 0 (its default state), software can read and write i/o registers during the break state without affecting status bits. some status bits have a 2-step read/write clearing procedure. if software does the first step on such a bit before the break, the bit cannot change during the break state as long as bcfe is at logic 0. after the break, doing the second step clears the status bit. 22.8 i/o signals port d shares one of its pins with the tima. port e shares two of its pins with the tima and port f shares four of its pins with the tima. ptd6/atd14/taclk is an external clock input to the tima prescaler. the six tima channel i/o pins are pte2/tach0, pte3/tach1, ptf0/tach2, ptf1/tach3, ptf2/tach4, and ptf3/tach5. 22.8.1 tima clock pin (ptd6/atd14/taclk) ptd6/atd14/taclk is an external clock input that can be the clock source for the tima counter instead of the prescaled internal bus clock. select the ptd6/atd14/taclk input by writing logic 1s to the three timer interface module a (tima) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 397 prescaler select bits, ps[2:0] (see tima status and control register). the minimum tclk pulse width, tclk lmin or tclk hmin , is: the maximum tclk frequency is the least: 4 mhz or bus frequency 2. ptd6/atd14/taclk is available as a general-purpose i/o pin or adc channel when not used as the tima clock input. when the ptd6/atd14/taclk pin is the tima clock input, it is an input regardless of the state of the ddrd6 bit in data direction register d. 22.8.2 tima channel i/o pins (ptf3/tach5 ? ptf0/tach2 and pte3/tach1 ? pte2/tach0) each channel i/o pin is programmable independently as an input capture pin or an output compare pin. pte2/tach0, ptf0/tach2 and ptf2/tach4 can be configured as buffered output compare or buffered pwm pins. 22.9 i/o registers these i/o registers control and monitor tima operation: tima status and control register (tasc) tima control registers (tacnth ? tacntl) tima counter modulo registers (tamodh ? tamodl) tima channel status and control registers (tasc0, tasc1, tasc2, tasc3, tasc4 and tasc5) tima channel registers (tach0h ? tach0l, tach1h ? tach1l, tach2h ? tach2l, tach3h ? tach3l, tach4h ? tach4l and tach5h ? tach5l) 1 bus frequency ------------------------------------- t su + timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 398 timer interface module a (tima) motorola 22.9.1 tima status and control register the tima status and control register: enables tima overflow interrupts flags tima overflows stops the tima counter resets the tima counter prescales the tima counter clock tof ? tima overflow flag bit this read/write flag is set when the tima counter reaches the modulo value programmed in the tima counter modulo registers. clear tof by reading the tima status and control register when tof is set and then writing a logic 0 to tof. if another tima overflow occurs before the clearing sequence is complete, then writing logic 0 to tof has no effect. therefore, a tof interrupt request cannot be lost due to inadvertent clearing of tof. reset clears the tof bit. writing a logic 1 to tof has no effect. 1 = tima counter has reached modulo value. 0 = tima counter has not reached modulo value. toie ? tima overflow interrupt enable bit this read/write bit enables tima overflow interrupts when the tof bit becomes set. reset clears the toie bit. 1 = tima overflow interrupts enabled 0 = tima overflow interrupts disabled address: $0020 bit 7654321bit 0 read: tof toie tstop 00 ps2 ps1 ps0 write: 0 trst r reset:00100000 r= reserved figure 22-4. tima status and control register (tasc) timer interface module a (tima) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 399 tstop ? tima stop bit this read/write bit stops the tima counter. counting resumes when tstop is cleared. reset sets the tstop bit, stopping the tima counter until software clears the tstop bit. 1 = tima counter stopped 0 = tima counter active note: do not set the tstop bit before entering wait mode if the tima is required to exit wait mode. also, when the tstop bit is set and input capture mode is enabled, input captures are inhibited until tstop is cleared. trst ? tima reset bit setting this write-only bit resets the tima counter and the tima prescaler. setting trst has no effect on any other registers. counting resumes from $0000. trst is cleared automatically after the tima counter is reset and always reads as logic 0. reset clears the trst bit. 1 = prescaler and tima counter cleared 0 = no effect note: setting the tstop and trst bits simultaneously stops the tima counter at a value of $0000. ps[2:0] ? prescaler select bits these read/write bits select either the ptd6/atd14/taclk pin or one of the seven prescaler outputs as the input to the tima counter as table 22-1 shows. reset clears the ps[2:0] bits. table 22-1. prescaler selection ps[2:0] tima clock source 000 internal bus clock 1 001 internal bus clock 2 010 internal bus clock 4 011 internal bus clock 8 100 internal bus clock 16 101 internal bus clock 32 110 internal bus clock 64 111 ptd6/atd14/taclk timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 400 timer interface module a (tima) motorola 22.9.2 tima counter registers the two read-only tima counter registers contain the high and low bytes of the value in the tima counter. reading the high byte (tacnth) latches the contents of the low byte (tacntl) into a buffer. subsequent reads of tacnth do not affect the latched tacntl value until tacntl is read. reset clears the tima counter registers. setting the tima reset bit (trst) also clears the tima counter registers. note: if tacnth is read during a break interrupt, be sure to unlatch tacntl by reading tacntl before exiting the break interrupt. otherwise, tacntl retains the value latched during the break. register name and address tacnth ? $0022 bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write:rrrrrrrr reset:00000000 register name and address tacntl ? $0023 bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write:rrrrrrrr reset:00000000 r = reserved figure 22-5. tima counter registers (tacnth and tacntl) timer interface module a (tima) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 401 22.9.3 tima counter modulo registers the read/write tima modulo registers contain the modulo value for the tima counter. when the tima counter reaches the modulo value, the overflow flag (tof) becomes set and the tima counter resumes counting from $0000 at the next timer clock. writing to the high byte (tamodh) inhibits the tof bit and overflow interrupts until the low byte (tamodl) is written. reset sets the tima counter modulo registers. note: reset the tima counter before writing to the tima counter modulo registers. register name and address tamodh ? $0024 bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write: reset:11111111 register name and address tamodl ? $0025 bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write: reset:11111111 figure 22-6. tima counter modulo registers (tamodh and tamodl) timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 402 timer interface module a (tima) motorola 22.9.4 tima channel status and control registers each of the tima channel status and control registers: flags input captures and output compares enables input capture and output compare interrupts selects input capture, output compare or pwm operation selects high, low or toggling output on output compare selects rising edge, falling edge or any edge as the active input capture trigger selects output toggling on tima overflow selects 0% and 100% pwm duty cycle selects buffered or unbuffered output compare/pwm operation timer interface module a (tima) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 403 register name and address tasc0 ? $0026 bit 7654321bit 0 read: ch0f ch0ie ms0b ms0a els0b els0a tov0 ch0max write: 0 reset:00000000 register name and address tasc1 ? $0029 bit 7654321bit 0 read: ch1f ch1ie 0 ms1a els1b els1a tov1 ch1max write: 0 r reset:00000000 r= reserved register name and address tasc2 ? $002c bit 7654321bit 0 read: ch2f ch2ie ms2b ms2a els2b els2a tov2 ch2max write: 0 reset:00000000 register name and address tasc3 ? $002f bit 7654321bit 0 read: ch3f ch3ie 0 ms3a els3b els3a tov3 ch3max write: 0 r reset:00000000 register name and address tasc4 ? $0032 bit 7654321bit 0 read: ch4f ch4ie ms4b ms4a els4b els4a tov4 ch4max write: 0 reset:00000000 register name and address tasc5 ? $0035 bit 7654321bit 0 read: ch5f ch5ie 0 ms5a els5b els5a tov5 ch5max write: 0 r reset:00000000 r = reserved figure 22-7. tima channel status and control registers (tasc0 ? tasc5) timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 404 timer interface module a (tima) motorola chxf ? channel x flag bit when channel x is an input capture channel, this read/write bit is set when an active edge occurs on the channel x pin. when channel x is an output compare channel, chxf is set when the value in the tima counter registers matches the value in the tima channel x registers. when chxie = 1, clear chxf by reading tima channel x status and control register with chxf set and then writing a logic 0 to chxf. if another interrupt request occurs before the clearing sequence is complete, then writing logic 0 to chxf has no effect. therefore, an interrupt request cannot be lost due to inadvertent clearing of chxf. reset clears the chxf bit. writing a logic 1 to chxf has no effect. 1 = input capture or output compare on channel x 0 = no input capture or output compare on channel x chxie ? channel x interrupt enable bit this read/write bit enables tima cpu interrupts on channel x. reset clears the chxie bit. 1 = channel x cpu interrupt requests enabled 0 = channel x cpu interrupt requests disabled msxb ? mode select bit b this read/write bit selects buffered output compare/pwm operation. msxb exists only in the tima channel 0, tima channel 2 and tima channel 4 status and control registers. setting ms0b disables the channel 1 status and control register and reverts tach1 pin to general-purpose i/o. setting ms2b disables the channel 3 status and control register and reverts tach3 pin to general-purpose i/o. setting ms4b disables the channel 5 status and control register and reverts tach5 pin to general-purpose i/o. reset clears the msxb bit. 1 = buffered output compare/pwm operation enabled 0 = buffered output compare/pwm operation disabled timer interface module a (tima) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 405 msxa ? mode select bit a when elsxb:a 00, this read/write bit selects either input capture operation or unbuffered output compare/pwm operation. see table 22-2 . 1 = unbuffered output compare/pwm operation 0 = input capture operation when elsxb:a = 00, this read/write bit selects the initial output level of the tachx pin once pwm, output compare mode or input capture mode is enabled. see table 22-2 . reset clears the msxa bit. 1 = initial output level low 0 = initial output level high note: before changing a channel function by writing to the msxb or msxa bit, set the tstop and trst bits in the tima status and control register (tasc). elsxb and elsxa ? edge/level select bits when channel x is an input capture channel, these read/write bits control the active edge-sensing logic on channel x. when channel x is an output compare channel, elsxb and elsxa control the channel x output behavior when an output compare occurs. when elsxb and elsxa are both clear, channel x is not connected to port e or port f and pin ptex/tachx or pin ptfx/tachx is available as a general-purpose i/o pin. however, channel x is at a state determined by these bits and becomes transparent to the respective pin when pwm, input capture mode or output compare operation mode is enabled. table 22-2 shows how elsxb and elsxa work. reset clears the elsxb and elsxa bits. timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 406 timer interface module a (tima) motorola note: before enabling a tima channel register for input capture operation, make sure that the ptex/tachx pin or ptfx/tachx pin is stable for at least two bus clocks. tovx ? toggle-on-overflow bit when channel x is an output compare channel, this read/write bit controls the behavior of the channel x output when the tima counter overflows. when channel x is an input capture channel, tovx has no effect. reset clears the tovx bit. 1 = channel x pin toggles on tima counter overflow. 0 = channel x pin does not toggle on tima counter overflow. note: when tovx is set, a tima counter overflow takes precedence over a channel x output compare if both occur at the same time. table 22-2. mode, edge, and level selection msxb:msxa elsxb:elsxa mode configuration x0 00 output preset pin under port control; initialize timer output level high x1 00 pin under port control; initialize timer output level low 00 01 input capture capture on rising edge only 00 10 capture on falling edge only 00 11 capture on rising or falling edge 01 01 output compare or pwm toggle output on compare 01 10 clear output on compare 01 11 set output on compare 1x 01 buffered output compare or buffered pwm toggle output on compare 1x 10 clear output on compare 1x 11 set output on compare timer interface module a (tima) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 407 chxmax ? channel x maximum duty cycle bit when the tovx bit is at logic 1, setting the chxmax bit forces the duty cycle of buffered and unbuffered pwm signals to 100%. as figure 22-8 shows, the chxmax bit takes effect in the cycle after it is set or cleared. the output stays at the 100% duty cycle level until the cycle after chxmax is cleared. figure 22-8. chxmax latency 22.9.5 tima channel registers these read/write registers contain the captured tima counter value of the input capture function or the output compare value of the output compare function. the state of the tima channel registers after reset is unknown. in input capture mode (msxb ? msxa = 0:0) reading the high byte of the tima channel x registers (tachxh) inhibits input captures until the low byte (tachxl) is read. in output compare mode (msxb ? msxa 0:0) writing to the high byte of the tima channel x registers (tachxh) inhibits output compares and the chxf bit until the low byte (tachxl) is written. output overflow ptex/tchx period chxmax overflow overflow overflow overflow compare output compare output compare output compare timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 408 timer interface module a (tima) motorola register name and address tach0h ? $0027 bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write: reset: indeterminate after reset register name and address tach0l ? $0028 bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write: reset: indeterminate after reset register name and address tach1h ? $002a bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write: reset: indeterminate after reset register name and address tach1l ? $002b bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write: reset: indeterminate after reset register name and address tach2h ? $002d bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write: reset: indeterminate after reset register name and address tach2l ? $002e bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write: reset: indeterminate after reset figure 22-9. tima channel registers (tach0h/l ? tach5h/l) (sheet 1 of 2) timer interface module a (tima) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola timer interface module a (tima) 409 register name and address tach3h ? $0030 bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write: reset: indeterminate after reset register name and address tach3l ? $0031 bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write: reset: indeterminate after reset register name and address tach4h ? $0033 bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write: reset: indeterminate after reset register name and address tach4l ? $0034 bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write: reset: indeterminate after reset register name and address tach5h ? $0036 bit 7654321bit 0 read: bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 write: reset: indeterminate after reset register name and address tach5l ? $0037 bit 7654321bit 0 read: bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 write: reset: indeterminate after reset figure 22-9. tima channel registers (tach0h/l ? tach5h/l) (sheet 2 of 2) timer interface module a (tima) technical data MC68HC08AZ32A ? rev 1.0 410 timer interface module a (tima) motorola MC68HC08AZ32A ? rev 1.0 technical data motorola analog-to-digital converter (adc-15) 411 technical data ? MC68HC08AZ32A section 23. analog-to-digital converter (adc-15) 23.1 contents 23.2 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412 23.3 features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412 23.4 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412 23.4.1 adc port i/o pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413 23.4.2 voltage conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414 23.4.3 conversion time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414 23.4.4 continuous conversion . . . . . . . . . . . . . . . . . . . . . . . . . . 415 23.4.5 accuracy and precision . . . . . . . . . . . . . . . . . . . . . . . . . . 415 23.5 interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415 23.6 low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415 23.6.1 wait mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415 23.6.2 stop mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416 23.7 i/o signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416 23.7.1 adc analog power pin (vddaref) . . . . . . . . . . . . . . . . 416 23.7.2 adc analog ground/adc voltage reference low pin (a vss /v refl ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416 23.7.4 adc voltage in (adcvin) . . . . . . . . . . . . . . . . . . . . . . . . 417 23.8 i/o registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417 23.8.1 adc status and control register . . . . . . . . . . . . . . . . . . 417 23.8.2 adc data register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420 23.8.3 adc input clock register . . . . . . . . . . . . . . . . . . . . . . . . 420 analog-to-digital converter (adc-15) technical data MC68HC08AZ32A ? rev 1.0 412 analog-to-digital converter (adc-15) motorola 23.2 introduction this section describes the analog-to-digital converter. the adc is an 8- bit analog-to-digital converter. for further information regarding analog-to-digital converters on motorola microcontrollers, please consult the hc08 adc reference manual, adcrm/ad. 23.3 features features of the adc module include: 15 channels with multiplexed input linear successive approximation 8-bit resolution single or continuous conversion conversion complete flag or conversion complete interrupt selectable adc clock 23.4 functional description fifteen adc channels are available for sampling external sources at pins ptd6/atd14/taclk ? ptd0/atd8 and ptb7/atd7 ? ptb0/atd0. an analog multiplexer allows the single adc converter to select one of 15 adc channels as adc voltage in (adcvin). adcvin is converted by the successive approximation register-based counters. when the conversion is completed, adc places the result in the adc data register and sets a flag or generates an interrupt. see figure 23-1 . analog-to-digital converter (adc-15) functional description MC68HC08AZ32A ? rev 1.0 technical data motorola analog-to-digital converter (adc-15) 413 figure 23-1. adc block diagram 23.4.1 adc port i/o pins ptd6/atd14/taclk ? ptd0/atd8 and ptb7/atd7 ? ptb0/atd0 are general-purpose i/o pins that share with the adc channels. the channel select bits define which adc channel/port pin will be used as the input signal. the adc overrides the port i/o logic by forcing that pin as input to the adc. the remaining adc channels/port pins are controlled by the port i/o logic and can be used as general-purpose i/o. writes to the port register or ddr will not have any affect on the port pin that is selected by the adc. read of a port pin which is in use by the internal data bus read ddrb/ddrb write ddrb/ddrd reset write ptb/ptd read ptb/ptd ptbx/ptdx ddrbx/ddrdx ptbx/ptdx interrupt logic channel select adc clock generator conversion complete adc voltage in adcvin adc clock cgmxclk bus clock adch[4:0] adc data register adiv[2:0] adiclk aien coco disable disable adc channel x analog-to-digital converter (adc-15) technical data MC68HC08AZ32A ? rev 1.0 414 analog-to-digital converter (adc-15) motorola adc will return a logic 0 if the corresponding ddr bit is at logic 0. if the ddr bit is at logic 1, the value in the port data latch is read. note: do not use adc channels atd14 or atd12 when using the ptd6/atd14/taclk or ptd4/atd12/tbclk pins as the clock inputs for the 16-bit timers. 23.4.2 voltage conversion when the input voltage to the adc equals v refh (see electrical specifications on page 423), the adc converts the signal to $ff (full scale). if the input voltage equals av ss /v refl, the adc converts it to $00. input voltages between v refh and av ss/ v refl are a straight-line linear conversion. conversion accuracy of all other input voltages is not guaranteed. avoid current injection on unused adc inputs to prevent potential conversion error. note: input voltage should not exceed the analog supply voltages. 23.4.3 conversion time conversion starts after a write to the adscr (adc status control register, $0038), and requires between 16 and 17 adc clock cycles to complete. conversion time in terms of the number of bus cycles is a function of adiclk select, cgmxclk frequency, bus frequency, and adiv prescaler bits. for example, with a cgmxclk frequency of 4 mhz, bus frequency of 8 mhz, and fixed adc clock frequency of 1 mhz, one conversion will take between 16 and 17 s and there will be between 128 bus cycles between each conversion. sample rate is approximately 60 khz. refer to electrical specifications on page 423. 16 to 17 adc clock cycles conversion time = ???????????? adc clock frequency number of bus cycles = conversion time x bus frequency analog-to-digital converter (adc-15) interrupts MC68HC08AZ32A ? rev 1.0 technical data motorola analog-to-digital converter (adc-15) 415 23.4.4 continuous conversion in the continuous conversion mode, the adc data register will be filled with new data after each conversion. data from the previous conversion will be overwritten whether that data has been read or not. conversions will continue until the adco bit (adc status control register, $0038) is cleared. the coco bit is set after the first conversion and will stay set for the next several conversions until the next write of the adc status and control register or the next read of the adc data register. 23.4.5 accuracy and precision the conversion process is monotonic and has no missing codes. see electrical specifications on page 423 for accuracy information. 23.5 interrupts when the aien bit is set, the adc module is capable of generating a cpu interrupt after each adc conversion. a cpu interrupt is generated if the coco bit (adc status control register, $0038) is at logic 0. if the coco bit is set, an interrupt is generated. the coco bit is not used as a conversion complete flag when interrupts are enabled. 23.6 low-power modes the following subsections describe the low-power modes. 23.6.1 wait mode the adc continues normal operation during wait mode. any enabled cpu interrupt request from the adc can bring the mcu out of wait mode. if the adc is not required to bring the mcu out of wait mode, power down the adc by setting the adch[4:0] bits in the adc status and control register before executing the wait instruction. analog-to-digital converter (adc-15) technical data MC68HC08AZ32A ? rev 1.0 416 analog-to-digital converter (adc-15) motorola 23.6.2 stop mode the adc module is inactive after the execution of a stop instruction. any pending conversion is aborted. adc conversions resume when the mcu exits stop mode. allow one conversion cycle to stabilize the analog circuitry before attempting a new adc conversion after exiting stop mode. 23.7 i/o signals the adc module has 15 channels that are shared with i/o ports b and d. refer to electrical specifications on page 423 for voltages referenced below. 23.7.1 adc analog power pin (v ddaref ) the adc analog portion uses v ddaref as its power pin. connect the v ddaref pin to the same voltage potential as v dd . external filtering may be necessary to ensure clean v ddaref for good results. note: route v ddaref carefully for maximum noise immunity and place bypass capacitors as close as possible to the package. v ddaref must be present for operation of the adc. 23.7.2 adc analog ground/adc voltage reference low pin (a vss /v refl ) the adc analog portion uses a vss /v refl as its ground pin. connect the a vss /v refl pin to the same voltage potential as v ss . v refl is the lower reference supply for the adc. 23.7.3 adc voltage reference pin (v refh ) v refh is the high reference voltage for all analog-to-digital conversions. analog-to-digital converter (adc-15) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola analog-to-digital converter (adc-15) 417 23.7.4 adc voltage in (adcvin) adcvin is the input voltage signal from one of the 15 adc channels to the adc module. 23.8 i/o registers these i/o registers control and monitor adc operation: adc status and control register (adscr) adc data register (adr) adc clock register (adiclk) 23.8.1 adc status and control register the following paragraphs describe the function of the adc status and control register. coco ? conversions complete bit when the aien bit is a logic 0, the coco is a read-only bit which is set each time a conversion is completed. this bit is cleared whenever the adc status and control register is written or whenever the adc data register is read. address: $0038 bit 7654321bit 0 read: coco aien adco adch4 adch3 adch2 adch1 adch0 write: r reset:00011111 r= reserved figure 23-2. adc status and control register (adscr) analog-to-digital converter (adc-15) technical data MC68HC08AZ32A ? rev 1.0 418 analog-to-digital converter (adc-15) motorola if the aien bit is a logic 1, the coco is a read/write bit which selects the cpu to service the adc interrupt request. reset clears this bit. 1 = conversion completed (aien = 0) 0 = conversion not completed (aien = 0) or cpu interrupt enabled (aien = 1) aien ? adc interrupt enable bit when this bit is set, an interrupt is generated at the end of an adc conversion. the interrupt signal is cleared when the data register is read or the status/control register is written. reset clears the aien bit. 1 = adc interrupt enabled 0 = adc interrupt disabled adco ? adc continuous conversion bit when set, the adc will convert samples continuously and update the adr register at the end of each conversion. only one conversion is allowed when this bit is cleared. reset clears the adco bit. 1 = continuous adc conversion 0 = one adc conversion adch[4:0] ? adc channel select bits adch4, adch3, adch2, adch1, and adch0 form a 5-bit field which is used to select one of 15 adc channels. channel selection is detailed in the following table. care should be taken when using a port pin as both an analog and a digital input simultaneously to prevent switching noise from corrupting the analog signal. see table 23-1 . the adc subsystem is turned off when the channel select bits are all set to one. this feature allows for reduced power consumption for the mcu when the adc is not used. reset sets these bits. note: recovery from the disabled state requires one conversion cycle to stabilize. analog-to-digital converter (adc-15) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola analog-to-digital converter (adc-15) 419 table 23-1. mux channel select adch4 adch3 adch2 adch1 adch0 input select 00000 ptb0/atd0 00001 ptb1/atd1 00010 ptb2/atd2 00011 ptb3/atd3 00100 ptb4/atd4 00101 ptb5/atd5 00110 ptb6/atd6 00111 ptb7/atd7 01000 ptd0/atd8 01001 ptd1/atd9 01010 ptd2/atd10 01011 ptd3/atd11 01100 ptd4/atd12/tbclk 01101 ptd5/atd13 01110 ptd6/atd14/taclk range 0 1111 ($0f) to 1 1010 ($1a) unused (see note 1) unused (see note 1) 11011 reserved 1 1 1 0 0 unused (see note 1) 1 1 1 0 1 v refh (see note 2) 1 1 1 1 0 av ss /v refl (see note 2) 1 1 1 1 1 [adc power off] notes: 1. if any unused channels are selected, the resulting adc conversion will be unknown. 2. the voltage levels supplied from internal reference nodes as specified in the table are used to verify the operation of the adc converter both in production test and for user applications. analog-to-digital converter (adc-15) technical data MC68HC08AZ32A ? rev 1.0 420 analog-to-digital converter (adc-15) motorola 23.8.2 adc data register one 8-bit result register is provided. this register is updated each time an adc conversion completes. 23.8.3 adc input clock register this register selects the clock frequency for the adc. adiv2 ? adiv0 ? adc clock prescaler bits adiv2, adiv1, and adiv0 form a 3-bit field which selects the divide ratio used by the adc to generate the internal adc clock. table 23- 2 shows the available clock configurations. the adc clock should be set to approximately 1 mhz. address: $0039 bit 7654321bit 0 read: ad7 ad6 ad5 ad4 ad3 ad2 ad1 ad0 write:rrrrrrrr reset: indeterminate after reset r= reserved figure 23-3. adc data register (adr) address: $003a bit 7654321bit 0 read: adiv2 adiv1 adiv0 adiclk 0000 write: rrrr reset: 0 0000000 r= reserved figure 23-4. adc input clock register (adiclk) analog-to-digital converter (adc-15) i/o registers MC68HC08AZ32A ? rev 1.0 technical data motorola analog-to-digital converter (adc-15) 421 adiclk ? adc input clock register bit adiclk selects either bus clock or cgmxclk as the input clock source to generate the internal adc clock. reset selects cgmxclk as the adc clock source. if the external clock (cgmxclk) is equal to or greater than 1 mhz, cgmxclk can be used as the clock source for the adc. if cgmxclk is less than 1 mhz, use the pll-generated bus clock as the clock source. as long as the internal adc clock is at approximately 1 mhz, correct operation can be guaranteed. see electrical specifications on page 423. 1 = internal bus clock 0 = external clock (cgmxclk) note: during the conversion process, changing the adc clock will result in an incorrect conversion. table 23-2. adc clock divide ratio adiv2 adiv1 adiv0 adc clock rate 0 0 0 adc input clock /1 0 0 1 adc input clock / 2 0 1 0 adc input clock / 4 0 1 1 adc input clock / 8 1 x x adc input clock / 16 x = don ? t care f xclk or bus frequency 1 mhz = ??????????? adiv[2:0] analog-to-digital converter (adc-15) technical data MC68HC08AZ32A ? rev 1.0 422 analog-to-digital converter (adc-15) motorola MC68HC08AZ32A ? rev 1.0 technical data motorola electrical specifications 423 technical data ? MC68HC08AZ32A section 24. electrical specifications 24.1 contents 24.2 maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424 24.3 functional operating range . . . . . . . . . . . . . . . . . . . . . . . . 425 24.4 thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425 24.5 5.0 volt dc electrical characteristics . . . . . . . . . . . . . . . . . 426 24.6 control timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427 24.7 adc characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428 24.8 5.0 vdc 0.5 v serial peripheral interface (spi) timing . . 429 24.9 cgm operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . 432 24.10 cgm component information . . . . . . . . . . . . . . . . . . . . . . . 433 24.11 cgm acquisition/lock time information . . . . . . . . . . . . . . 434 24.12 ram memory characteristics . . . . . . . . . . . . . . . . . . . . . . . 435 24.13 eeprom memory characteristics . . . . . . . . . . . . . . . . . . . 435 24.14 mechanical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . 436 24.14.1 64-pin quad flat pack (qfp) . . . . . . . . . . . . . . . . . . . . . . 436 electrical specifications technical data MC68HC08AZ32A ? rev 1.0 424 electrical specifications motorola 24.2 maximum ratings maximum ratings are the extreme limits to which the mcu can be exposed without permanently damaging it. note: this device is not guaranteed to operate at the maximum ratings. refer to 5.0 volt dc electrical characteristics for guaranteed operating conditions. note: this device contains circuitry to protect the inputs against damage due to high static voltages or electric fields; however, it is advised that normal precautions be taken to avoid application of any voltage higher than maximum-rated voltages to this high-impedance circuit. for proper operation, it is recommended that v in and v out be constrained to the range v ss (v in or v out ) v dd . reliability of operation is enhanced if unused inputs are connected to an appropriate logic voltage level (for example, either v ss or v dd ). rating symbol value unit supply voltage v dd ? 0.3 to +6.0 v input voltage v in v ss ? 0.3 to v dd +0.3 v maximum current per pin excluding v dd and v ss i 25 ma storage temperature t stg ? 55 to +150 c maximum current out of v ss i mvss 100 ma maximum current into v dd i mvdd 100 ma reset and irq input voltage v hi v dd + 4.5 v note: voltages are referenced to v ss . electrical specifications functional operating range MC68HC08AZ32A ? rev 1.0 technical data motorola electrical specifications 425 24.3 functional operating range note: for applications which use the lvi, motorola guarantee the functionality of the device down to the lvi trip point (v lvi ) within the constraints outlined in low voltage inhibit (lvi) on page 173. 24.4 thermal characteristics notes: 1. power dissipation is a function of temperature. 2. k is a constant unique to the device. k can be determined from a known t a and measured p d. with this value of k, p d , and t j can be determined for any value of t a . rating symbol value unit operating temperature range (1) 1. t a (max) =125 c for part suffix mfu 105 c for part suffix vfu 85 c for part suffix cfu t a ? 40 to t a (max) c operating voltage range v dd 5.0 0.5v v characteristic symbol value unit thermal resistance qfp (64 pins) ja 70 c/w i/o pin power dissipation p i/o user determined w power dissipation (see note 1) p d p d = (i dd x v dd ) + p i/o = k/(t j + 273 c w constant (see note 2) k p d x (t a + 273 c) + (p d 2 x ja ) w/ c average junction temperature t j t a = p d x ja c electrical specifications technical data MC68HC08AZ32A ? rev 1.0 426 electrical specifications motorola 24.5 5.0 volt dc electrical characteristics characteristic symbol min max unit output high voltage (i load = ? 2.0 ma) all ports v oh v dd ? 0.8 ? v (i load = ? 5.0 ma) all ports v dd ? 1.5 ? v total source current i oh(tot) ? 10 ma output low voltage (i load = 1.6 ma) all ports v ol ? 0.4 v (i load = 10.0 ma) all ports ? 1.5 v to t a l s in k cu rr e n t i ol(tot) ? 15 ma input high voltage all ports, irq s , reset, osc1 v ih 0.7 x v dd v dd v input low voltage all ports, irq s , reset, osc1 v il v ss 0.3 x v dd v v dd + v dda supply current run (see note 2)(see note 9) wait (see note 3)(see note 9) stop (see note 4) 25 c ? 40 c to +125 c 25 c with lvi enabled ? 40 c to +125 c with lvi enabled i dd ? ? ? ? ? ? 30 14 50 100 400 500 ma ma a a a a i/o ports hi-z leakage current i l ? 11 a i/o ports hi-z leakage current (see note 11) i l ? 10 10 a input current i in ? 11 a input current (see note 11) i in ? 10 10 a capacitance ports (as input or output) c out c in ? ? 12 8 pf low-voltage reset inhibit (trip) (recover) v lvi 3.80 4.49 v por rearm voltage (see note 5) v por 0 200 mv por reset voltage (see note 6) v porrst 0 800 mv por rise time ramp rate (see note 7) r por 0.02 ? v/ms high cop disable voltage (see note 8) v hi v dd + 3 v dd + 4.5 v electrical specifications control timing MC68HC08AZ32A ? rev 1.0 technical data motorola electrical specifications 427 24.6 control timing monitor mode entry voltage on irq (see note 10) v hi v dd + 3 v dd + 4.5 v 1.v dd = 5.0 vdc 0.5v, v ss = 0 vdc, t a = ? 40 c to t a (max) , unless otherwise noted. 2.run (operating) i dd measured using external square wave clock source (f bus = 8.4 mhz). all inputs 0.2 v from rail. no dc loads. less than 100 pf on all outputs. c l = 20 pf on osc2. all ports configured as inputs. osc2 capaci- tance linearly affects run i dd . measured with all modules enabled. 3.wait i dd measured using external square wave clock source (f bus = 8.4 mhz). all inputs 0.2 vdc from rail. no dc loads. less than 100 pf on all outputs, c l = 20 pf on osc2. all ports configured as inputs. osc2 capacitance linearly affects wait i dd . measured with all modules enabled. 4.stop i dd measured with osc1 = v ss . 5.maximum is highest voltage that por is guaranteed. 6.maximum is highest voltage that por is possible. 7.if minimum v dd is not reached before the internal por reset is released, rst must be driven low externally until minimum v dd is reached. 8.see computer operating properly (cop) on page 167. v hi applied to rst . 9.although i dd is proportional to bus frequency, a current of several ma is present even at very low frequencies. 10.see monitor mode description within computer operating properly (cop) on page 167. v hi applied to irq or rst . 11.when subjected to a human body model (hbm) esd event as specified in aec q100-002 these pins may exhibit recov- erable leakage values within the specification indicated. characteristic symbol min max unit bus operating frequency (4.5 ? 5.5 v ? v dd only) f bus ? 8.4 mhz internal clock period (1/f bus ) t cyc 119 ? ns reset pulse width low t rl 1.5 ? t cyc irq interrupt pulse width low (edge-triggered) t ilhi 1.5 ? t cyc irq interrupt pulse period t ilil note 3 ? t cyc 16-bit timer input capture pulse width (see note 2) input capture period input clock pulse width t th, t tl t tltl t tch, t tcl 2 note 3 (1/f op ) + 5 ? ? ? t cyc t cyc ns mscan wake-up filter pulse width (see note 4) t wup 25 s 1.v dd = 5.0 vdc 0.5v, v ss = 0 vdc, t a = ? 40 c to t a (max) , unless otherwise noted. 2.refer to table 17-2 and table 22-2 and supporting notes. 3.the minimum period t tltl or t ilil should not be less than the number of cycles it takes to execute the capture interrupt service routine plus t cyc . 4. the minimum pulse width to wake up the mscan module is guaranteed by design but not tested. electrical specifications technical data MC68HC08AZ32A ? rev 1.0 428 electrical specifications motorola 24.7 adc characteristics characteristic min max unit comments resolution 8 8 bits absolute accuracy (v refl = 0 v, v dda = v refh = 5 v 0.5v) ? 1+1lsb includes quantization conversion range (see note 1) v refl v refh v v refl = v ssa power-up time 16 17 s conversion time period input leakage (see note 3) ports b and d ? 11 a input leakage (see note 4) ports b and d ? 10 10 a conversion time 16 17 adc clock cycles includes sampling time monotonicity inherent within total error zero input reading 00 01 hex v in = v refl full-scale reading fe ff hex v in = v refh sample time (see note 2) 5 ? adc clock cycles input capacitance ? 8pf not tested adc internal clock 500 k 1.048 m hz tested only at 1 mhz analog input voltage v refl v refh v 1.v dd = 5.0 vdc 0.5v, v ss = 0 vdc, v dda /v ddaref = 5.0 vdc 0.5v, v ssa = 0 vdc, v refh = 5.0 vdc 0.5v 2.source impedances greater than 10 k ? adversely affect internal rc charging time during input sampling. 3.the external system error caused by input leakage current is approximately equal to the product of r source and input current. 4.when subjected to a human body model (hbm) esd event as specified in aec q100-002 these pins may exhibit recoverable leakage values within the specification indicated. electrical specifications 5.0 vdc 0.5 v serial peripheral interface (spi) timing MC68HC08AZ32A ? rev 1.0 technical data motorola electrical specifications 429 24.8 5.0 vdc 0.5 v serial peripheral interface (spi) timing num characteristic symbol min max unit operating frequency (see note 3) master slave f bus( m ) f bus( s ) f bus /128 dc f bus /2 f bus mhz 1 cycle time master slave t cyc( m ) t cyc( s ) 2 1 128 ? t cyc 2 enable lead time t lead 15 ? ns 3 enable lag time t lag 15 ? ns 4 clock (sck) high time master slave t w(sckh)m t w(sckh)s 100 50 ? ? ns 5 clock (sck) low time master slave t w(sckl)m t w(sckl)s 100 50 ? ? ns 6 data setup time (inputs) master slave t su(m) t su(s) 45 5 ? ? ns 7 data hold time (inputs) master slave t h(m) t h(s) 0 15 ? ? ns 8 access time, slave (see note 4) cpha = 0 cpha = 1 t a(cp0) t a(cp1) 0 0 40 20 ns 9 slave disable time (hold time to high-impedance state) t dis ? 25 ns 10 enable edge lead time to data valid (see note 6) master slave t ev(m) t ev(s) ? ? 10 40 ns 11 data hold time (outputs, after enable edge) master slave t ho(m) t ho(s) 0 5 ? ? ns 12 data valid master (before capture edge) t v(m) 90 ? ns 13 data hold time (outputs) master (after capture edge) t ho(m) 100 ? ns notes: 1. all timing is shown with respect to 30% v dd and 70% v dd , unless otherwise noted; assumes 100 pf load on all spi pins. 2. item numbers refer to dimensions in figure 24-1 and figure 24-2 . 3. f bus = the currently active bus frequency for the microcontroller. 4. time to data active from high-impedance state. 5. with 100 pf on all spi pins electrical specifications technical data MC68HC08AZ32A ? rev 1.0 430 electrical specifications motorola figure 24-1. spi master timing diagram note note: this first clock edge is generated internally, but is not seen at the sck pin. ss pin of master held high. msb in ss (input) sck (cpol = 0) (output) sck (cpol = 1) (output) miso (input) mosi (output) note 4 5 5 1 4 bits 6 ? 1 lsb in master msb out bits 6 ? 1 master lsb out 10 11 10 11 7 6 note note: this last clock edge is generated internally, but is not seen at the sck pin. ss pin of master held high. msb in ss (input) sck (cpol = 0) (output) sck (cpol = 1) (output) miso (input) mosi (output) note 4 5 5 1 4 bits 6 ? 1 lsb in master msb out bits 6 ? 1 master lsb out 10 11 10 11 7 6 a) spi master timing (cpha = 0) b) spi master timing (cpha = 1) 12 13 12 13 electrical specifications 5.0 vdc 0.5 v serial peripheral interface (spi) timing MC68HC08AZ32A ? rev 1.0 technical data motorola electrical specifications 431 figure 24-2. spi slave timing diagram note: not defined but normally msb of character just received slave ss (input) sck (cpol = 0) (input) sck (cpol = 1) (input) miso (input) mosi (output) 4 5 5 1 4 msb in bits 6 ? 1 8 6 10 11 11 note slave lsb out 9 3 lsb in 2 7 bits 6 ? 1 msb out note: not defined but normally lsb of character previously transmitted slave ss (input) sck (cpol = 0) (input) sck (cpol = 1) (input) miso (output) mosi (input) 4 5 5 1 4 msb in bits 6 ? 1 8 6 10 note slave lsb out 9 3 lsb in 2 7 bits 6 ? 1 msb out 10 a) spi slave timing (cpha = 0) b) spi slave timing (cpha = 1) 11 11 electrical specifications technical data MC68HC08AZ32A ? rev 1.0 432 electrical specifications motorola 24.9 cgm operating conditions 1. f cgmvrs is a nominal value described and calculated as an example in the clock generator module (cgm) section for the desired vco operating frequency, f cgmvclk . characteristic symbol min typ max unit comments operating voltage v dd a v dd -0.3 ? v dd +0.3 v v ssa v ss -0.3 ? v ss +0.3 v crystal reference frequency f cgmrclk 1 4.9152 16 mhz module crystal reference frequency f cgmxclk ? 4.9152 ? mhz same frequency as f cgmrclk range nom. multiplier f nom ? 4.9152 ? mhz vco center-of-range frequency f cgmvrs 4.9152 ? note 1 mhz vco operating frequency f cgmvclk 4.9152 ? 32.0 electrical specifications cgm component information MC68HC08AZ32A ? rev 1.0 technical data motorola electrical specifications 433 24.10 cgm component information description symbol min typ max unit comments crystal load capacitance c l ?? ?? consult crystal manufacturer ? s data crystal fixed capacitance c1 ? 2 x cl ?? consult crystal manufacturer ? s data crystal tuning capacitance c2 ? 2 x cl ?? consult crystal manufacturer ? s data filter capacitor multiply factor c fact ? 0.0154 ? f/s v filter capacitor c f ? c fact x (v dda / f cgmxclk ) ?? see external filter capacitor pin (cgmxfc) on page 129 . bypass capacitor c byp ? 0.1 f ? f cbyp must provide low ac impedance from f = f cgmxclk /100 to 100 x f cgmvclk , so series resistance must be considered. electrical specifications technical data MC68HC08AZ32A ? rev 1.0 434 electrical specifications motorola 24.11 cgm acquisition/lock time information description symbol min typ max unit notes manual mode time to stable t acq ? (8 x v dda ) / (f cgmxclk x k acq) ? s if c f chosen correctly manual stable to lock time t al ? (4 x v dda ) / (f cgmxclk x k trk ) ? s if c f chosen correctly manual acquisition time t lock ? t acq +t al ? s tracking mode entry frequency tolerance d trk 0 ? 3.6 % acquisition mode entry frequency tolerance d unt 6.3 ? 7.2 % lock entry freq. tolerance d lock 0 ? 0.9 % lock exit freq. tolerance d unl 0.9 ? 1.8 % reference cycles per acquisition mode measurement n acq ? 32 ?? reference cycles per tracking mode measurement n trk ? 128 ?? automatic mode time to stable t acq n acq /f cgm xclk (8 x v dda ) / (f cgmxclk x k acq) s if c f chosen correctly automatic stable to lock time t al n trk /f cgm xclk (4 x v dda ) / (f cgmxclk x k trk ) ? s if c f chosen correctly automatic lock time t lock ? 0.65 25 ms pll jitter, deviation of average bus frequency over 2 ms (note 1) 0 ? (f crys ) x (.025%) x (n/4) % n = vco freq. mult. k value for automatic mode time to stable k acq ? 0.2 ?? k value k trk ? 0.004 ?? notes: 1. guaranteed but not tested. 2. v dd = 5.0 vdc 0.5 v, v ss = 0 vdc, t a = -40c to t a (max), unless otherwise noted. 3. conditions for typical and maximum values are for run mode with f cgmxclk = 8mhz, f busdes = 8mhz, n = 4, l = 7, discharged c f = 15 nf, v dd = 5vdc. 4. refer to phase-locked loop (pll) section for guidance on the use of the pll. electrical specifications ram memory characteristics MC68HC08AZ32A ? rev 1.0 technical data motorola electrical specifications 435 24.12 ram memory characteristics 24.13 eeprom memory characteristics characteristic symbol min max unit ram data retention voltage v rdr 0.7 ? v characteristic symbol min max unit eeprom programming time per byte t eepgm 10 ? ms eeprom erasing time per byte t eebyte 10 ? ms eeprom erasing time per block t eeblock 10 ? ms eeprom erasing time per bulk t eebulk 10 ? ms eeprom programming voltage discharge period t eefpv 100 ? s number of programming operations to the same eeprom byte before erase (1) ?? 8 ? eeprom write/erase cycles @ 10 ms write time ? 10,000 ? cycles eeprom data retention after 10,000 write/erase cycles ? 10 ? years eeprom programming maximum time to ? auto ? bit set ?? 500 s eeprom erasing maximum time to ? auto ? bit set ?? 8ms notes: 1. programming a byte more times than the specified maximum may affect the data integrity of that byte. the byte must be erased before it can be programmed again. electrical specifications technical data MC68HC08AZ32A ? rev 1.0 436 electrical specifications motorola 24.14 mechanical specifications 24.14.1 64-pin quad flat pack (qfp) figure 24-3. 64-pin qfp (case #840b) 0.20 m ca ? b s d s l 33 48 16 1 32 17 49 64 - b - b v 0.05 a ? b - d - a s 0.20 m ha ? b s d s l - a - detail ? a ? b b - a, b, d - p detail ? a ? f n j d section b ? b base metal g h e c -c- m detail ? c ? m -h- datum plane seating plane u t r q k w x dim. min. max. notes dim. min. max. a 13.90 14.10 1. datum plane ? h ? is located at bottom of lead and is coincident with the lead where the lead exits the plastic body at the bottom of the parting line. 2. datums a ? b and ? d to be determined at datum plane ? h ? . 3. dimensions s and v to be determined at seating plane ? c ? . 4. dimensions a and b do not include mould protrusion. allowable mould protrusion is 0.25mm per side. dimensions a and b do include mould mismatch and are determined at datum plane ? h ? . 5. dimension d does not include dambar protrusion. allowable dambar protrusion shall be 0.08 total in excess of the d dimension at maximum material condition. dambar cannot be located on the lower radius or the foot. 6. dimensions and tolerancing per ansi y 14.5m, 1982. 7. all dimensions in mm. m5 10 b 13.90 14.10 n 0.13 0.17 c 2.15 2.45 p 0.40 bsc d 0.30 0.45 q 0 7 e 2.00 2.40 r 0.13 0.30 f 0.30 0.40 s 16.95 17.45 g 0.80 bsc t 0.13 ? h ? 0.25 u 0 ? j 0.13 0.23 v 16.95 17.45 k 0.65 0.95 w 0.35 0.45 l 12.00 ref x 1.6 ref 0.20 m ca ? b s d s 0.05 a ? b 0.20 m ha ? b s d s 0.20 m ca ? b s d s MC68HC08AZ32A ? rev 1.0 technical data motorola MC68HC08AZ32A changes 437 technical data ? MC68HC08AZ32A section 25. MC68HC08AZ32A changes 25.1 contents 25.2 significant changes from the mc68hc08az32 (non-a suffix device) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25.2437 25.2.1 ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437 25.2.2 monitor rom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438 25.2.3 eeprom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438 25.2.4 mask option registers . . . . . . . . . . . . . . . . . . . . . . . . . . 439 25.2.5 analog to digital converter . . . . . . . . . . . . . . . . . . . . . . . 440 25.2.6 timer interface module a . . . . . . . . . . . . . . . . . . . . . . . . 440 25.2.7 rom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440 25.2.8 illegal address reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441 25.2.9 monitor mode entry and cop disable voltage . . . . . . . 441 25.2.10 low-voltage inhibit (lvi) . . . . . . . . . . . . . . . . . . . . . . . . . 441 25.2.11 cgm acquisition/lock time information . . . . . . . . . . . . 441 25.2 significant changes from the mc68hc08az32 (non-a suffix device) 25.2.1 ordering information hc08ab and hc08az16/24 devices have been removed from the ordering information. the older hc08az32 used to be parent silicon for ab family devices. this is no longer the case and custom ab silicon exists. similarly, smaller memory size hc08az parts are no longer available and customers should order the hc08az32a. MC68HC08AZ32A changes technical data MC68HC08AZ32A ? rev 1.0 438 MC68HC08AZ32A changes motorola 25.2.2 monitor rom the monitor rom is now allocated 320 bytes within the memory map though not all that space is necessarily used. functionality of the monitor rom is unchanged. 25.2.3 eeprom 25.2.3.1 eeprom architecture the eeprom is made from a new nvm technology. however, the bit polarity remains the same i.e. programmed=0, erased=1. the architecture and basic programming and erase operations are unchanged. 25.2.3.2 eeprom clock source and pre-scaler the first major difference on the new eeprom is that it requires a constant time base source to ensure secure programming and erase operations. this is done by firstly selecting which clock source is going to drive the eediv clock divider input using a new bit 7 introduced onto the morb mask option register $fe09. next the divide ratio from this source has to be set by programming an 11-bit time base pre-scalar into bits spread over two new registers, eedivh and eedivl. the eedivh and eedivl registers are volatile. however, they are loaded upon reset by the contents of duplicate non-volatile eedivhnvr and eedivlnvr registers much in the same way as the array control register (eeacr) interacts with the non-volatile register (eenvr) for configuration control on the existing revision. as a result of the new eediv clock described above, bit 7 (eebclk) of the eeprom control register (eecr) is no longer used. MC68HC08AZ32A changes significant changes from the mc68hc08az32 (non-a suffix device) MC68HC08AZ32A ? rev 1.0 technical data motorola MC68HC08AZ32A changes 439 25.2.3.3 eeprom auto programming & erasing the second major change to the eeprom is the inclusion in the eeprom control register (eecr) of an auto function using previously unused bit 1 of that register. the auto function enables the logic of the mcu to automatically use the optimum programming or erasing time for the eeprom. if using auto the user does not need to wait for the normal minimum specified programming or erasing time. after setting the eepgm bit as normal the user just has to poll that bit again, waiting for the mcu to clear it indicating that programming or erasing is complete. 25.2.4 mask option registers 25.2.4.1 mask option register a the mask option register a is changed to bring it into line with the majority of other hc08as & az family devices. although the changes are minor, the implications of the change are major so users should pay particular attention when choosing the mask options to be programmed into rom especially if code execution depends upon reads of this register. as always, users should check carefully the mor selections of any device since minor differences within families often exist. bit 2, coprs has changed in polarity such that when selected as a ? 1 ? a short cop timeout time out period of 8176 cycles is enabled. bit 4, lvipwr was previously lvipwrd i.e. when selected as a ? 1 ? the lvi power is now enabled and not disabled. bit 5, lvirst was previously lvirstd i.e. when selected as a ? 1 ? the lvi enables the reset signal from the lvi module and does not disable. bits 0,1,3, 6 and 7 remain unchanged from the previous revision. however, bit 6 (romsec) now works, enabling rom security. previously, this function did not work and was an errata on non-a versions. MC68HC08AZ32A changes technical data MC68HC08AZ32A ? rev 1.0 440 MC68HC08AZ32A changes motorola 25.2.4.2 mask option register b mask option register b has been moved from address $003f to $fe09, and has 3 new bits activated. bit 3 is now a silicon hard set bit, which identifies this new a-suffix silicon (1) from the previous non-a suffix silicon (0). bit 4 is a bit that can enable eeprom read protection when in monitor mode. bit 7 is now an eeprom time base divider clock select bit selecting the reference clock source for the eeprom time base divider module (refer to eeprom changes described above). 25.2.5 analog to digital converter previously the user had to select at rom submission if a 15-channel converter was desired as opposed to only 8-channel. this is no longer selectable and the new default is that every mcu will be configured with a 15-channel analog to digital converter. 25.2.6 timer interface module a the tima is now a 6 channel timer rather than just 4 channel as before. additional vectors are allocated to the area $ffcc - $ffcf that were previously mapped as rom area. 25.2.7 rom as a result of adding the extra 2 tima channels described above, the 16 bytes of rom mapped to locations $ffc0 - $ffcf is now no longer available. this reduces the total rom bytes available from 32,272 to 32,256 bytes. MC68HC08AZ32A changes significant changes from the mc68hc08az32 (non-a suffix device) MC68HC08AZ32A ? rev 1.0 technical data motorola MC68HC08AZ32A changes 441 25.2.8 illegal address reset only an opcode fetch from an illegal address will generate an illegal address reset. data fetches from unmapped addresses will not generate a reset. 25.2.9 monitor mode entry and cop disable voltage the monitor mode entry and cop disable voltage specifications (v hi ) have been increased. please see electrical specifications for details. 25.2.10 low-voltage inhibit (lvi) the low-voltage inhibit (lvi) specifications for trip and recovery voltage (v lvi ) have been altered based upon module performance on silicon. please see for electrical specifications details. 25.2.11 cgm acquisition/lock time information please note that revised k values can be found in the electrical specifications section. MC68HC08AZ32A changes technical data MC68HC08AZ32A ? rev 1.0 442 MC68HC08AZ32A changes motorola MC68HC08AZ32A ? rev 1.0 technical data motorola revision history 443 technical data ? MC68HC08AZ32A revision history major changes between revision 1.0 and revision 0.0 the following table lists the major changes between the current revision of the MC68HC08AZ32A technical data book, rev 1.0, and the previous revision, rev 0.0. section affected description of change general description corrected text in numerous pin desriptions. corrected table 1-1 - external pins summary with which pins have hysteresis. added missing modules to table 1-3 - clock source summary memory map corrected type errors. corrected various addresses and register names in figure 2-1 - memory map . corrected numerous register bit descriptions in figure 2-2 - i/o data, status and control registers to match module sections. added additional status and control registers section and moved register descriptions accordingly. corrected bit descriptions to match module sections. eeprom section altered significantly to better align module descriptions across groups within motorola using 0.5 tsmc/sst flash. numerous additions submitted by applications engineering for further clarification of functional operation. clock generator module (cgm) corrected clock signal names and associated timing parameters for consistency and to match signal naming conventions. additional textual description added to reaction time calculation subsection. mask options corrected descriptions of lvirst and lvipwr bits break module corrected description of brkscr register system integration module (sim) corrected various type errors in sbsr and sbfcr register bit descriptions monitor rom (mon) modified figure 11-1 - monitor mode circuit based upon recommendations from applications engineering. corrected type errors. corrected figure 11-6 - monitor mode entry timing . revision history technical data MC68HC08AZ32A ? rev 1.0 444 revision history motorola computer operating properly (cop) corrected references to copl (now coprs). corrected type errors. low voltage inhibit (lvi) corrected functional description and revised figure 13-1 - lvi module block diagram external interrupt module (irq) corrected iscr register bit descriptions. timer interface module b (timb) corrected numerous type and grammatical errors. corrected numerous pin and register name errors within text. corrected references to timb overflow interrupts (removed "channel x" references as they are incorrect). corrected functional description on tof flag. programmable interrupt timer (pit) corrected type and grammatical errors. corrected pit overflow interrupt enable bit acronym from pie to poie. mscan08 included extended id errata information as new subsection 20.6.1 added address definitions to figure 20-9 - mscan08 memory map. keyboard module (kbd) added low power modes subsection. timer interface module a (tima) corrected numerous type and grammatical errors. corrected numerous pin and register name errors within text. corrected references to tima overflow interrupts (removed "channel x" references as they are incorrect). corrected functional description of tof flag. electrical specifications corrected type errors. increased v hi specification in maximum ratings to v dd + 4.5v. decreased lvi trip voltage specification to 3.80v and increased lvi recovery voltage to 4.49v in 5.0 volt dc electrical characteristics . increased vhi specification to minimum of v dd + 3.0v and maximum of v dd + 4.5v in 5.0 volt dc electrical characteristics . added unit columns to all cgm specification tables and adjusted text accordingly. corrected operating voltage specification in cgm operating conditions . added typical specifications for k acq and k trk parameters in cgm acquisition/lock time information . split memory characteristics table into separate ram memory characteristics and eeprom memory characteristics . added maximum specification for eeprom auto bit set for each of program and erase operation in eeprom memory characteristics . MC68HC08AZ32A changes added subsection highlighting operation of iar function. added subsection highlighting change of monitor mode entry and cop disable voltage change. added subsection highlighting change in lvi trip and recovery voltage specifications. added subsection highlighting revised k values. section affected description of change mc68hc908az60a ? rev 2.0 technical data motorola glossary 445 technical data ? mc68hc908az60a glossary a ? see ? accumulator (a). ? accumulator (a) ? an 8-bit general-purpose register in the cpu08. the cpu08 uses the accumulator to hold operands and results of arithmetic and logic operations. acquisition mode ? a mode of pll operation during startup before the pll locks on a frequency. also see "tracking mode." address bus ? the set of wires that the cpu or dma uses to read and write memory locations. addressing mode ? the way that the cpu determines the operand address for an instruction. the m68hc08 cpu has 16 addressing modes. alu ? see ? arithmetic logic unit (alu). ? arithmetic logic unit (alu) ? the portion of the cpu that contains the logic circuitry to perform arithmetic, logic, and manipulation operations on operands. asynchronous ? refers to logic circuits and operations that are not synchronized by a common reference signal. baud rate ? the total number of bits transmitted per unit of time. bcd ? see ? binary-coded decimal (bcd). ? binary ? relating to the base 2 number system. binary number system ? the base 2 number system, having two digits, 0 and 1. binary arithmetic is convenient in digital circuit design because digital circuits have two permissible voltage levels, low and high. the binary digits 0 and 1 can be interpreted to correspond to the two digital voltage levels. binary-coded decimal (bcd) ? a notation that uses 4-bit binary numbers to represent the 10 decimal digits and that retains the same positional structure of a decimal number. for example, 234 (decimal) = 0010 0011 0100 (bcd) bit ? a binary digit. a bit has a value of either logic 0 or logic 1. glossary technical data mc68hc908az60a ? rev 2.0 446 glossary motorola branch instruction ? an instruction that causes the cpu to continue processing at a memory location other than the next sequential address. break module ? a module in the m68hc08 family. the break module allows software to halt program execution at a programmable point in order to enter a background routine. breakpoint ? a number written into the break address registers of the break module. when a number appears on the internal address bus that is the same as the number in the break address registers, the cpu executes the software interrupt instruction (swi). break interrupt ? a software interrupt caused by the appearance on the internal address bus of the same value that is written in the break address registers. bus ? a set of wires that transfers logic signals. bus clock ? the bus clock is derived from the cgmout output from the cgm. the bus clock frequency, f op , is equal to the frequency of the oscillator output, cgmxclk, divided by four. byte ? a set of eight bits. c ? the carry/borrow bit in the condition code register. the cpu08 sets the carry/borrow bit when an addition operation produces a carry out of bit 7 of the accumulator or when a subtraction operation requires a borrow. some logical operations and data manipulation instructions also clear or set the carry/borrow bit (as in bit test and branch instructions and shifts and rotates). ccr ? see ? condition code register. ? central processor unit (cpu) ? the primary functioning unit of any computer system. the cpu controls the execution of instructions. cgm ? see ? clock generator module (cgm). ? clear ? to change a bit from logic 1 to logic 0; the opposite of set. clock ? a square wave signal used to synchronize events in a computer. clock generator module (cgm) ? a module in the m68hc08 family. the cgm generates a base clock signal from which the system clocks are derived. the cgm may include a crystal oscillator circuit and or phase-locked loop (pll) circuit. comparator ? a device that compares the magnitude of two inputs. a digital comparator defines the equality or relative differences between two binary numbers. computer operating properly module (cop) ? a counter module in the m68hc08 family that resets the mcu if allowed to overflow. glossary mc68hc908az60a ? rev 2.0 technical data motorola glossary 447 condition code register (ccr) ? an 8-bit register in the cpu08 that contains the interrupt mask bit and five bits that indicate the results of the instruction just executed. control bit ? one bit of a register manipulated by software to control the operation of the module. control unit ? one of two major units of the cpu. the control unit contains logic functions that synchronize the machine and direct various operations. the control unit decodes instructions and generates the internal control signals that perform the requested operations. the outputs of the control unit drive the execution unit, which contains the arithmetic logic unit (alu), cpu registers, and bus interface. cop ? see "computer operating properly module (cop)." counter clock ? the input clock to the tim counter. this clock is the output of the tim prescaler. cpu ? see ? central processor unit (cpu). ? cpu08 ? the central processor unit of the m68hc08 family. cpu clock ? the cpu clock is derived from the cgmout output from the cgm. the cpu clock frequency is equal to the frequency of the oscillator output, cgmxclk, divided by four. cpu cycles ? a cpu cycle is one period of the internal bus clock, normally derived by dividing a crystal oscillator source by two or more so the high and low times will be equal. the length of time required to execute an instruction is measured in cpu clock cycles. cpu registers ? memory locations that are wired directly into the cpu logic instead of being part of the addressable memory map. the cpu always has direct access to the information in these registers. the cpu registers in an m68hc08 are: a (8-bit accumulator) h:x (16-bit index register) sp (16-bit stack pointer) pc (16-bit program counter) ccr (condition code register containing the v, h, i, n, z, and c bits) csic ? customer-specified integrated circuit cycle time ? the period of the operating frequency: t cyc =1/f op . decimal number system ? base 10 numbering system that uses the digits zero through nine. glossary technical data mc68hc908az60a ? rev 2.0 448 glossary motorola direct memory access module (dma) ? a m68hc08 family module that can perform data transfers between any two cpu-addressable locations without cpu intervention. for transmitting or receiving blocks of data to or from peripherals, dma transfers are faster and more code-efficient than cpu interrupts. dma ? see "direct memory access module (dma)." dma service request ? a signal from a peripheral to the dma module that enables the dma module to transfer data. duty cycle ? a ratio of the amount of time the signal is on versus the time it is off. duty cycle is usually represented by a percentage. eeprom ? electrically erasable, programmable, read-only memory. a nonvolatile type of memory that can be electrically reprogrammed. eprom ? erasable, programmable, read-only memory. a nonvolatile type of memory that can be erased by exposure to an ultraviolet light source and then reprogrammed. exception ? an event such as an interrupt or a reset that stops the sequential execution of the instructions in the main program. external interrupt module (irq) ? a module in the m68hc08 family with both dedicated external interrupt pins and port pins that can be enabled as interrupt pins. fetch ? to copy data from a memory location into the accumulator. firmware ? instructions and data programmed into nonvolatile memory. free-running counter ? a device that counts from zero to a predetermined number, then rolls over to zero and begins counting again. full-duplex transmission ? communication on a channel in which data can be sent and received simultaneously. h ? the upper byte of the 16-bit index register (h:x) in the cpu08. h ? the half-carry bit in the condition code register of the cpu08. this bit indicates a carry from the low-order four bits of the accumulator value to the high-order four bits. the half-carry bit is required for binary-coded decimal arithmetic operations. the decimal adjust accumulator (daa) instruction uses the state of the h and c bits to determine the appropriate correction factor. hexadecimal ? base 16 numbering system that uses the digits 0 through 9 and the letters a through f. high byte ? the most significant eight bits of a word. glossary mc68hc908az60a ? rev 2.0 technical data motorola glossary 449 illegal address ? an address not within the memory map illegal opcode ? a nonexistent opcode. i ? the interrupt mask bit in the condition code register of the cpu08. when i is set, all interrupts are disabled. index register (h:x) ? a 16-bit register in the cpu08. the upper byte of h:x is called h. the lower byte is called x. in the indexed addressing modes, the cpu uses the contents of h:x to determine the effective address of the operand. h:x can also serve as a temporary data storage location. input/output (i/o) ? input/output interfaces between a computer system and the external world. a cpu reads an input to sense the level of an external signal and writes to an output to change the level on an external signal. instructions ? operations that a cpu can perform. instructions are expressed by programmers as assembly language mnemonics. a cpu interprets an opcode and its associated operand(s) and instruction. interrupt ? a temporary break in the sequential execution of a program to respond to signals from peripheral devices by executing a subroutine. interrupt request ? a signal from a peripheral to the cpu intended to cause the cpu to execute a subroutine. i/o ? see ? input/output (i/0). ? irq ? see "external interrupt module (irq)." jitter ? short-term signal instability. latch ? a circuit that retains the voltage level (logic 1 or logic 0) written to it for as long as power is applied to the circuit. latency ? the time lag between instruction completion and data movement. least significant bit (lsb) ? the rightmost digit of a binary number. logic 1 ? a voltage level approximately equal to the input power voltage (v dd ). logic 0 ? a voltage level approximately equal to the ground voltage (v ss ). low byte ? the least significant eight bits of a word. low voltage inhibit module (lvi) ? a module in the m68hc08 family that monitors power supply voltage. glossary technical data mc68hc908az60a ? rev 2.0 450 glossary motorola lvi ? see "low voltage inhibit module (lvi)." m68hc08 ? a motorola family of 8-bit mcus. mark/space ? the logic 1/logic 0 convention used in formatting data in serial communication. mask ? 1. a logic circuit that forces a bit or group of bits to a desired state. 2. a photomask used in integrated circuit fabrication to transfer an image onto silicon. mask option ? a optional microcontroller feature that the customer chooses to enable or disable. mask option register (mor) ? an eprom location containing bits that enable or disable certain mcu features. mcu ? microcontroller unit. see ? microcontroller. ? memory location ? each m68hc08 memory location holds one byte of data and has a unique address. to store information in a memory location, the cpu places the address of the location on the address bus, the data information on the data bus, and asserts the write signal. to read information from a memory location, the cpu places the address of the location on the address bus and asserts the read signal. in response to the read signal, the selected memory location places its data onto the data bus. memory map ? a pictorial representation of all memory locations in a computer system. microcontroller ? microcontroller unit (mcu). a complete computer system, including a cpu, memory, a clock oscillator, and input/output (i/o) on a single integrated circuit. modulo counter ? a counter that can be programmed to count to any number from zero to its maximum possible modulus. monitor rom ? a section of rom that can execute commands from a host computer for testing purposes. mor ? see "mask option register (mor)." most significant bit (msb) ? the leftmost digit of a binary number. multiplexer ? a device that can select one of a number of inputs and pass the logic level of that input on to the output. n ? the negative bit in the condition code register of the cpu08. the cpu sets the negative bit when an arithmetic operation, logical operation, or data manipulation produces a negative result. nibble ? a set of four bits (half of a byte). glossary mc68hc908az60a ? rev 2.0 technical data motorola glossary 451 object code ? the output from an assembler or compiler that is itself executable machine code, or is suitable for processing to produce executable machine code. opcode ? a binary code that instructs the cpu to perform an operation. open-drain ? an output that has no pullup transistor. an external pullup device can be connected to the power supply to provide the logic 1 output voltage. operand ? data on which an operation is performed. usually a statement consists of an operator and an operand. for example, the operator may be an add instruction, and the operand may be the quantity to be added. oscillator ? a circuit that produces a constant frequency square wave that is used by the computer as a timing and sequencing reference. otprom ? one-time programmable read-only memory. a nonvolatile type of memory that cannot be reprogrammed. overflow ? a quantity that is too large to be contained in one byte or one word. page zero ? the first 256 bytes of memory (addresses $0000 ? $00ff). parity ? an error-checking scheme that counts the number of logic 1s in each byte transmitted. in a system that uses odd parity, every byte is expected to have an odd number of logic 1s. in an even parity system, every byte should have an even number of logic 1s. in the transmitter, a parity generator appends an extra bit to each byte to make the number of logic 1s odd for odd parity or even for even parity. a parity checker in the receiver counts the number of logic 1s in each byte. the parity checker generates an error signal if it finds a byte with an incorrect number of logic 1s. pc ? see ? program counter (pc). ? peripheral ? a circuit not under direct cpu control. phase-locked loop (pll) ? a oscillator circuit in which the frequency of the oscillator is synchronized to a reference signal. pll ? see "phase-locked loop (pll)." pointer ? pointer register. an index register is sometimes called a pointer register because its contents are used in the calculation of the address of an operand, and therefore points to the operand. polarity ? the two opposite logic levels, logic 1 and logic 0, which correspond to two different voltage levels, v dd and v ss . polling ? periodically reading a status bit to monitor the condition of a peripheral device. port ? a set of wires for communicating with off-chip devices. glossary technical data mc68hc908az60a ? rev 2.0 452 glossary motorola prescaler ? a circuit that generates an output signal related to the input signal by a fractional scale factor such as 1/2, 1/8, 1/10 etc. program ? a set of computer instructions that cause a computer to perform a desired operation or operations. program counter (pc) ? a 16-bit register in the cpu08. the pc register holds the address of the next instruction or operand that the cpu will use. pull ? an instruction that copies into the accumulator the contents of a stack ram location. the stack ram address is in the stack pointer. pullup ? a transistor in the output of a logic gate that connects the output to the logic 1 voltage of the power supply. pulse-width ? the amount of time a signal is on as opposed to being in its off state. pulse-width modulation (pwm) ? controlled variation (modulation) of the pulse width of a signal with a constant frequency. push ? an instruction that copies the contents of the accumulator to the stack ram. the stack ram address is in the stack pointer. pwm period ? the time required for one complete cycle of a pwm waveform. ram ? random access memory. all ram locations can be read or written by the cpu. the contents of a ram memory location remain valid until the cpu writes a different value or until power is turned off. rc circuit ? a circuit consisting of capacitors and resistors having a defined time constant. read ? to copy the contents of a memory location to the accumulator. register ? a circuit that stores a group of bits. reserved memory location ? a memory location that is used only in special factory test modes. writing to a reserved location has no effect. reading a reserved location returns an unpredictable value. reset ? to force a device to a known condition. rom ? read-only memory. a type of memory that can be read but cannot be changed (written). the contents of rom must be specified before manufacturing the mcu. sci ? see "serial communication interface module (sci)." serial ? pertaining to sequential transmission over a single line. glossary mc68hc908az60a ? rev 2.0 technical data motorola glossary 453 serial communications interface module (sci) ? a module in the m68hc08 family that supports asynchronous communication. serial peripheral interface module (spi) ? a module in the m68hc08 family that supports synchronous communication. set ? to change a bit from logic 0 to logic 1; opposite of clear. shift register ? a chain of circuits that can retain the logic levels (logic 1 or logic 0) written to them and that can shift the logic levels to the right or left through adjacent circuits in the chain. signed ? a binary number notation that accommodates both positive and negative numbers. the most significant bit is used to indicate whether the number is positive or negative, normally logic 0 for positive and logic 1 for negative. the other seven bits indicate the magnitude of the number. software ? instructions and data that control the operation of a microcontroller. software interrupt (swi) ? an instruction that causes an interrupt and its associated vector fetch. spi ? see "serial peripheral interface module (spi)." stack ? a portion of ram reserved for storage of cpu register contents and subroutine return addresses. stack pointer (sp) ? a 16-bit register in the cpu08 containing the address of the next available storage location on the stack. start bit ? a bit that signals the beginning of an asynchronous serial transmission. status bit ? a register bit that indicates the condition of a device. stop bit ? a bit that signals the end of an asynchronous serial transmission. subroutine ? a sequence of instructions to be used more than once in the course of a program. the last instruction in a subroutine is a return from subroutine (rts) instruction. at each place in the main program where the subroutine instructions are needed, a jump or branch to subroutine (jsr or bsr) instruction is used to call the subroutine. the cpu leaves the flow of the main program to execute the instructions in the subroutine. when the rts instruction is executed, the cpu returns to the main program where it left off. synchronous ? refers to logic circuits and operations that are synchronized by a common reference signal. tim ? see "timer interface module (tim)." glossary technical data mc68hc908az60a ? rev 2.0 454 glossary motorola timer interface module (tim) ? a module used to relate events in a system to a point in time. timer ? a module used to relate events in a system to a point in time. toggle ? to change the state of an output from a logic 0 to a logic 1 or from a logic 1 to a logic 0. tracking mode ? mode of low-jitter pll operation during which the pll is locked on a frequency. also see "acquisition mode." two ? s complement ? a means of performing binary subtraction using addition techniques. the most significant bit of a two ? s complement number indicates the sign of the number (1 indicates negative). the two ? s complement negative of a number is obtained by inverting each bit in the number and then adding 1 to the result. unbuffered ? utilizes only one register for data; new data overwrites current data. unimplemented memory location ? a memory location that is not used. writing to an unimplemented location has no effect. reading an unimplemented location returns an unpredictable value. executing an opcode at an unimplemented location causes an illegal address reset. v ? the overflow bit in the condition code register of the cpu08. the cpu08 sets the v bit when a two's complement overflow occurs. the signed branch instructions bgt, bge, ble, and blt use the overflow bit. variable ? a value that changes during the course of program execution. vco ? see "voltage-controlled oscillator." vector ? a memory location that contains the address of the beginning of a subroutine written to service an interrupt or reset. voltage-controlled oscillator (vco) ? a circuit that produces an oscillating output signal of a frequency that is controlled by a dc voltage applied to a control input. waveform ? a graphical representation in which the amplitude of a wave is plotted against time. wired-or ? connection of circuit outputs so that if any output is high, the connection point is high. word ? a set of two bytes (16 bits). write ? the transfer of a byte of data from the cpu to a memory location. x ? the lower byte of the index register (h:x) in the cpu08. z ? the zero bit in the condition code register of the cpu08. the cpu08 sets the zero bit when an arithmetic operation, logical operation, or data manipulation produces a result of $00. how to reach us: usa/europe/locations not listed: motorola literature distribution p.o. box 5405 denver, colorado 80217 1-303-675-2140 1-800-441-2447 technical information center: 1-800-521-6274 japan: motorola japan ltd. sps, technical information center 3-20-1, minami-azabu, minato-ku tokyo 106-8573 japan 81-3-3440-3569 asia/pacific: motorola semiconductors h.k. ltd. silicon harbour centre 2 dai king street tai po industrial estate tai po, n.t., hong kong 852-26668334 home page: http://www.motorola.com/semiconductors/ mc68hc 0 8 az32a / d rev 1.0 |
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