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max7456 single-channel monochrome on-screen display with integrated eeprom ________________________________________________________________ maxim integrated products 1 19-0576; rev 0; 8/07 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. general description the max7456 single-channel monochrome on-screen display (osd) generator lowers system cost by elimi- nating the need for an external video driver, sync sepa- rator, video switch, and eeprom. the max7456 serves all national and international markets with 256 user-pro- grammable characters in ntsc and pal standards. the max7456 easily displays information such as com- pany logo, custom graphics, time, and date with arbi- trary characters and sizes. the max7456 is preloaded with 256 characters and pictographs and can be repro- grammed in-circuit using the spi tm port. the max7456 is available in a 28-pin tssop package and is fully specified over the extended (-40? to +85?) temperature range. applications security switching systems security cameras industrial applications in-cabin entertainment consumer electronics features ? 256 user-defined characters or pictographs in integrated eeprom ? 12 x 18 pixel character size ? blinking, inverse, and background control character attributes ? selectable brightness by row ? displays up to 16 rows x 30 characters ? sag compensation on video-driver output ? los, vsync , hsync , and clock outputs ? internal sync generator ? ntsc and pal compatible ? spi-compatible serial interface ? delivered with preprogrammed character set ordering information part pin-package language pkg code MAX7456EUI+ 28 tssop-ep* english/ japanese u28e-5 * ep = exposed pad. + denotes a lead-free package. note: this device is specified over the -40? to +85? operat- ing temperature range. pin configuration appears at end of data sheet. serial interface display address video driver video timing generator display memory (srams) character address pixel code sync pixel control character memory (nvm) osd generator sag network osd mux dac system clock por sync separator xtal oscillator clamp vin clkin xfb clkout reset hsync vsync los cs sclk sdin sdout avdd agnd dvdd dgnd pvdd pgnd vout sag max7456 simplified functional diagram spi is a trademark of motorola, inc.
max7456 single-channel monochrome on-screen display with integrated eeprom 2 _______________________________________________________________________________________ absolute maximum ratings stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. avdd to agnd ........................................................-0.3v to +6v dvdd to dgnd ........................................................-0.3v to +6v pvdd to pgnd.........................................................-0.3v to +6v agnd to dgnd.....................................................-0.3v to +0.3v agnd to pgnd .....................................................-0.3v to +0.3v dgnd to pgnd.....................................................-0.3v to +0.3v vin, vout, sag to agnd......................-0.3v to (v avdd + 0.3v) hsync , vsync , los to agnd ...............................-0.3v to +6v reset to agnd .....................................-0.3v to (v avdd + 0.3v) clkin, clkout, xfb to dgnd ............-0.3v to (v dvdd + 0.3v) sdin, sclk, cs , sdout to dgnd........-0.3v to (v dvdd + 0.3v) maximum continuous current into v out ........................?00ma continuous power dissipation (t a = +70?) 28-pin tssop (derate 27mw/? above +70?) .......2162mw* operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-60? to +150? lead temperature (soldering, 10s) .................................+300? electrical characteristics (v avdd = +4.75v to +5.25v, v dvdd = +4.75v to +5.25v, v pvdd = +4.75v to +5.25v, t a = t min to t max . typical values are at v avdd = v dvdd = v pvdd = +5v, t a = +25?, unless otherwise noted.) (note 1) parameter symbol conditions min typ max units power supplies analog supply voltage v avdd 4.75 5 5.25 v digital supply voltage v dvdd 4.75 5 5.25 v driver supply voltage v pvdd 4.75 5 5.25 v analog supply current i avdd v in = 1v p-p (100% white flat field signal), vout load, r l = 150 ? 24 35 ma digital supply current i dvdd v in = 1v p-p (100% white flat field signal), vout load, r l = 150 ? 25 30 ma driver supply current i pvdd v in = 1v p-p (100% white flat field signal), vout load, r l = 150 ? 58 80 ma nonvolatile memory data retention t a = +25? 100 years endurance t a = +25? 100,000 stores digital inputs ( cs , sdin, reset , sclk) input high voltage v ih 2.0 v input low voltage v il 0.8 v input hysteresis v hys 50 mv input leakage current v in = 0 or v dvdd ?0 ? input capacitance c in 5pf digital outputs (sdout, clkout, vsync , hsync , los) output high voltage v oh i source = 4ma (sdout, clkout) 2.4 v output low voltage v ol i sink = 4ma 0.45 v tri-state leakage current sdout, cs = v dvdd ?0 ? * as per jedec51 standard (multilayer board).
max7456 single-channel monochrome on-screen display with integrated eeprom _______________________________________________________________________________________ 3 electrical characteristics (continued) (v avdd = +4.75v to +5.25v, v dvdd = +4.75v to +5.25v, v pvdd = +4.75v to +5.25v, t a = t min to t max . typical values are at v avdd = v dvdd = v pvdd = +5v, t a = +25?, unless otherwise noted.) (note 1) parameter symbol conditions min typ max units clock input (clkin) clock frequency 27 mhz clock-pulse high 14 ns clock-pulse low 14 ns input high voltage 0.7 x v dvdd v input low voltage 0.3 x v dvdd v input leakage current v in = 0v or v dvdd ?0 ? clock output (clkout) duty cycle 5pf and 10k ? to dgnd 40 50 60 % rise time 5pf and 10k ? to dgnd 3 ns fall time 5pf and 10k ? to dgnd 3 ns video characteristics dc power-supply rejection v avdd = v dvdd = v pvdd = 5v; v in = 1v p-p , measured at vout 40 db ac power-supply rejection v avdd = v dvdd = v pvdd = 5v; v in = 1v p-p , measured at vout; f = 5mhz; power-supply ripple = 0.2v p-p 30 db short-circuit current vout to pgnd 230 ma line-time distortion ltd figures 1a, 1b 0.5 % output impedance z out figures 1a, 1b 0.2 ? gain figures 1a, 1b 1.89 2.0 2.11 v/v black level at vout, figures 1a, 1b agnd + 1.5 v input-voltage operating range v in figures 1a, 3 (note 2) 0.5 1.2 v p-p input-voltage sync detection range v insd figures 1a, 3 (note 3) 0.5 2.0 v p-p maximum output-voltage swing v out figures 1a, 1b 2.4 v p-p output-voltage sync tip level 0.7 v large signal bandwidth (0.2db) bw v out = 2v p-p , figures 1a, 1b 6 mhz vin to vout delay 30 ns differential gain dg 0.5 % differential phase dp 0.5 degrees osd white level vout 100% white level with respect to black level 1.25 1.33 1.45 v horizontal pixel jitter between consecutive horizontal lines 24 ns video clamp settling time 32 lines
max7456 single-channel monochrome on-screen display with integrated eeprom 4 _______________________________________________________________________________________ timing characteristics (v avdd = +4.75v to +5.25v, v dvdd = +4.75v to +5.25v, v pvdd = +4.75v to +5.25v, t a = t min to t max . typical values are at v avdd = v dvdd = v pvdd = +5v, t a = +25?, unless otherwise noted.) (note 1) parameter symbol conditions min typ max units spi timing sclk period t cp 100 ns sclk pulse-width high t ch 40 ns sclk pulse-width low t cl 40 ns cs fall to sclk rise setup t css0 30 ns cs fall after sclk rise hold t csh0 0ns cs rise to sclk setup t css1 30 ns cs rise after sclk hold t csh1 0ns cs pulse-width high t csw 100 ns sdin to sclk setup t ds 30 ns sdin to sclk hold t dh 0ns sdout valid before sclk t do1 20pf to ground 25 ns sdout valid after sclk t do2 20pf to ground 0 ns cs high to sdout high impedance t do3 20pf to ground 300 ns cs low to sdout logic level t do4 20pf to ground 20 ns hsync , vsync , and los timing los, vsync , and hsync valid before clkout rising edge t dov 20pf to ground 30 ns ntsc external sync mode, figure 4 375 vout sync to vsync falling edge delay t vout-vsf pal external sync mode, figure 6 400 ns electrical characteristics (continued) (v avdd = +4.75v to +5.25v, v dvdd = +4.75v to +5.25v, v pvdd = +4.75v to +5.25v, t a = t min to t max . typical values are at v avdd = v dvdd = v pvdd = +5v, t a = +25?, unless otherwise noted.) (note 1) parameter symbol conditions min typ max units osd characteristics osd rise time osd insertion mux register osdm[5,4,3] = 011b 60 ns osd fall time osd insertion mux register osdm[5,4,3] = 011b 60 ns osd insertion mux switch time osd insertion mux register osdm[2,1,0] = 011b 75 ns
max7456 single-channel monochrome on-screen display with integrated eeprom _______________________________________________________________________________________ 5 note 1: see the standard test circuits of figure 1. r l = 75 ? , unless otherwise specified. all digital input signals are timed from a voltage level of (v ih + v il ) / 2. all parameters are tested at t a = +85? and values through temperature range are guaran- teed by design. note 2: the input-voltage operating range is the input range over which the output signal parameters are guaranteed (figure 3). note 3: the input-voltage sync detection range is the input composite video range over which an input sync signal is properly detected and the osd signal appears at vout. however, the output voltage specifications are not guaranteed for input sig- nals exceeding the maximum specified in the input operating voltage range (figure 3). timing characteristics (continued) (v avdd = +4.75v to +5.25v, v dvdd = +4.75v to +5.25v, v pvdd = +4.75v to +5.25v, t a = t min to t max . typical values are at v avdd = v dvdd = v pvdd = +5v, t a = +25?, unless otherwise noted.) (note 1) parameter symbol conditions min typ max units ntsc external sync mode, figure 4 400 vout sync to vsync rising edge delay t vout-vsr pal external sync mode, figure 6 425 ns ntsc internal sync mode, figure 5 40 vsync falling edge to vout sync delay t vsf-vout pal internal sync mode, figure 7 45 ns ntsc internal sync mode, figure 5 32 vsync rising edge to vout sync delay t vsr-vout pal internal sync mode, figure 7 30 ns vout sync to hsync falling edge delay t vout-hsf ntsc and pal external sync mode, figure 8 310 ns vout sync to hsync rising edge delay t vout-hsr ntsc and pal external sync mode, figure 8 325 ns hsync falling edge to vout sync delay t hsf-vout ntsc and pal internal sync mode, figure 9 115 ns hsync rising edge to vout sync delay t hsr-vout ntsc and pal internal sync mode, figure 9 115 ns all supplies high to cs low t pud power-up delay 50 ms nvm write busy t nvw 12 ms c in 0.1 f r in 75 ? a) input test circuit vin sag c l 22pf r l 150 ? b) one standard video load, dc-coupled vout signal gen max7456 max7456 figure 1. standard test circuits
max7456 single-channel monochrome on-screen display with integrated eeprom 6 _______________________________________________________________________________________ image with on-screen graphics max7456 toc01 10 s/div 100% color bars response cvbs out (200mv/div) max7456 toc02 75% color bars vector diagram cvbs out max7456 toc03 10 s/div 60% multiburst response cvbs out (200mv/div) max7456 toc04 typical operating characteristics (v avdd = +5v, v dvdd = +5v, v pvdd = +5v, t a = +25?, unless otherwise noted. see the typical operating circuit of figure 2, if applicable.)
max7456 single-channel monochrome on-screen display with integrated eeprom _______________________________________________________________________________________ 7 10 s/div 100% sweep response cvbs out (200mv/div) max7456 toc05 differential phase max7456 toc06 step differential phase (deg) 6th 5th 4th 3rd 2nd 1st 0 0.05 0.10 cvbs out 0.15 0.20 -0.05 differential gain max7456 toc07 step differential gain (%) 6th 5th 4th 3rd 2nd 1st 0 0.05 0.10 0.15 0.20 -0.05 cvbs out 400ns/div 2t response cvbs in (200mv/div) cvbs out (200mv/div) max7456 toc08 400ns/div 12.5t response cvbs in (200mv/div) cvbs out (200mv/div) max7456 toc09 200ns/div osd output 100% white pixel cvbs out (200mv/div) max7456 toc10 typical operating characteristics (continued) (v avdd = +5v, v dvdd = +5v, v pvdd = +5v, t a = +25?, unless otherwise noted. see the typical operating circuit of figure 2, if applicable.)
max7456 single-channel monochrome on-screen display with integrated eeprom 8 _______________________________________________________________________________________ typical operating characteristics (continued) (v avdd = +5v, v dvdd = +5v, v pvdd = +5v, t a = +25?, unless otherwise noted. see the typical operating circuit of figure 2, if applicable.) 10 s/div line-time distortion cvbs out (200mv/div) max7456 toc11 2 s/div h timing (external-sync mode) cvbs out (200mv/div) max7456 toc12 2 s/div h timing (internal-sync mode) cvbs out (200mv/div) max7456 toc13 500 s/div loss-of-sync (low to high) cvbs out (200mv/div) los (1v/div) max7456 toc14 500 s/div loss-of-sync (high to low) cvbs out (200mv/div) los (1v/div) max7456 toc15
max7456 single-channel monochrome on-screen display with integrated eeprom _______________________________________________________________________________________ 9 pin description pin name function 1, 2, 13?6, 27, 28 n.c. no connection. not internally connected. 3 dvdd digital power-supply input. bypass to dgnd with a 0.1? capacitor. 4 dgnd digital ground 5 clkin crystal connection 1. connect a parallel resonant, fundamental mode crystal between clkin and xfb for use as a crystal oscillator, or drive clkin directly with a 27mhz system reference clock. 6 xfb crystal connection 2. connect a parallel resonant, fundamental mode crystal between clkin and xfb for use as a crystal oscillator, or leave xfb unconnected when driving clkin with a 27mhz system reference clock. 7 clkout clock output. 27mhz logic-level output system clock. 8 cs active-low chip-select input. sdout goes high impedance when cs is high. 9 sdin serial data input. data is clocked in at rising edge of sclk. 10 sclk serial clock input. clocks data into sdin and out of sdout. duty cycle must be between 40% and 60%. 11 sdout serial data output. data is clocked out at the falling edge of sclk. high impedance when cs is high. 12 los loss-of-sync output (open-drain). los goes high when the vin sync pulse is lost for 32 consecutive lines. los goes low when 32 consecutive valid sync pulses are received. connect to a 1k ? pullup resistor to dvdd or another positive supply voltage suitable for the receiving device. 17 vsync vertical sync output (open-drain). vsync goes low following the video input? vertical sync interval. vsync is either recovered from vin or internally generated when in internal sync mode. connect to a 1k ? pullup resistor to dvdd or another positive supply voltage suitable for the receiving device. 18 hsync horizontal sync output (open-drain). hsync goes low following the video input? horizontal sync interval. hsync is either recovered from vin or internally generated when in internal sync mode. connect to a 1k ? pullup resistor to dvdd or another positive supply voltage suitable for the receiving device. 19 reset system reset input. the minimum reset pulse width is 50ms. all spi registers are reset to their default values after 100? following the rising edge of reset . these registers are not accessible for reading or writing during that time. the display memory is reset to its default value of 00h in all locations after 20? following the rising edge of reset . 20 agnd analog ground 21 avdd analog power-supply input. bypass to agnd with a 0.1? capacitor. 22 vin pal or ntsc cvbs video input 23 pgnd driver ground. connect to agnd at a single point. 24 pvdd driver power-supply input. bypass to pgnd with a 0.1? capacitor. 25 sag sag correction input. connect to vout if not used. see figure 1b. 26 vout video output ?p exposed pad. internally connected to agnd. connect ep to the agnd plane for improved heat dissipation. do not use ep as the only ground connection.
max7456 single-channel monochrome on-screen display with integrated eeprom 10 ______________________________________________________________________________________ detailed description the max7456 single-channel monochrome on-screen display (osd) generator integrates all the functions need- ed to generate a user-defined osd and insert it into the output signal. the max7456 accepts a composite ntsc or pal video signal. the device includes an input clamp, sync separator, video timing generator, osd insertion mux, nonvolatile character memory, display memory, osd generator, crystal oscillator, an spi-compatible inter- face to read/write the osd data, and a video driver (see the simplified functional diagram ). additionally, the max7456 provides vertical sync ( vsync ), horizontal sync ( hsync ), and loss-of sync (los) outputs for system synchronization. a clock output signal (clkout) allows daisy-chaining of multiple devices. see the max7456 register description section for an explanation of register notation use in this data sheet. the 256 user-defined 12 x 18 pixel character set comes preloaded and is combined with the input video stream to generate a cvbs signal with osd video out- put. a maximum of 256 12 x 18 pixel characters can be reprogrammed in the nvm. in ntsc mode, 13 rows x 30 characters are displayed. in pal mode, 16 rows x 30 characters are displayed. when the input video sig- nal is absent, the osd image can still be displayed by using the max7456? internal video timing generator. video input the max7456 accepts standard ntsc or pal cvbs signals at vin. the video signal input must be ac-cou- pled with a 0.1? capacitor and is internally clamped. an input coupling capacitance of 0.1? is required to guarantee the specified line-time distortion (ltd) and video clamp settling time. the video clamp settling time changes proportionally to the input coupling capaci- tance, and ltd changes inversely proportional to the capacitance. 28 27 26 25 24 23 22 21 20 19 18 17 16 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 max7456 sdin +5v 27mhz sdout +5v cvbs out sag pgnd reset hsync vsync dgnd clkin xfb clkout cs sdin sclk sdout los n.c. sclk cs cvbs in los vs hs n.c. n.c. n.c. clkout n.c. n.c. agnd n.c. n.c. +5v 0.1 f c out 75 ? 75 ? 1k ? 1k ? 1k ? 0.1 f 0.1 f 0.1 f c sag dvdd vout pvdd vin avdd figure 2. typical operating circuit
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 11 input clamp the max7456? clamp is a dc-restore circuit that uses the input coupling capacitor to correct any dc shift of the input signal, on a line-by-line basis, such that the sync tip at vin is approximately 550mv. this establish- es a dc level at vin suitable for the on-chip sync detection and video processing functions. this circuitry also removes low-frequency noise such as 60hz hum or other additive low-frequency noise. sync separator the sync separator detects the composite sync pulses on the video input and extracts the timing information to generate hsync and vsync . it is also used for inter- nal osd synchronization and loss-of-sync (los) detec- tion. los goes high if no sync signal is detected at vin for 32 consecutive lines, and goes low if 32 consecu- tive horizontal sync signals are detected. during a los condition, when vm0[5] = 0 (video mode 0 register, bit 5), only the osd appears at the vout. at this time, the input image is set to a gray level at vout as deter- mined by vm1[6:4]. the behavior of all sync modes is shown in table 1. color burst sync tip level black level white level maximum video swing input voltage minimum video swing vin figure 3. definition of terms video mode vin vsync hsync los vout video active active low v in + osd auto sync select mode vm0[5, 4] = 0x no input active active high osd only video active active low v in + osd external sync select vm0[5, 4] = 10 no input inactive (high) inactive (high) high dc video active active high osd only internal sync select vm0[5, 4] = 11 no input active active high osd only table 1. video sync modes x = don? care.
max7456 single-channel monochrome on-screen display with integrated eeprom 12 ______________________________________________________________________________________ video timing generator the video timing generator is a digital circuit generat- ing all internal and external ( vsync and hsync ) tim- ing signals. vsync and hsync can be synchronized to vin, or run independently of any input when in inter- nal sync mode. the video timing generator can gener- ate ntsc or pal timing using the same 27mhz crystal (see figures 4?). crystal oscillator the internal crystal oscillator generates the system clock used by the video timing generator. the oscillator uses a 27mhz crystal or can be driven by an external 27mhz ttl clock at clkin. for external clock mode, connect the 27mhz ttl input clock to clkin and leave xfb unconnected. display memory (sram) the display memory stores 480 character addresses that point to the characters stored in the nvm character memory. the content of the display memory is user- programmable through the spi-compatible serial inter- face. the display-memory address corresponds to a fixed location on a monitor (see figure 10). momentary breakup of the osd image can be prevented by writing to the display memory during the vertical blanking inter- val. this can be achieved by using vsync as an inter- rupt to the host processor to initiate writing to the display memory. t vout-vsf 1/2h vertical synchronization pulse interval vout (odd field) vout (even field) vsync hsync (odd field) hsync (even field) 50% 50% t vout-vsr 50% 50% 50% figure 4. vout, vsync , and hsync timing (ntsc, external sync mode)
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 13 t vsf-vout 1/2h vertical synchronization pulse interval vout (odd field) vout (even field) vsync hsync (odd field) hsync (even field) 50% 50% t vsr-vout 50% 50% 50% 50% figure 5. vout, vsync , and hsync timing (ntsc, internal sync mode)
max7456 single-channel monochrome on-screen display with integrated eeprom 14 ______________________________________________________________________________________ t vout-vsf t vout-vsr 1/2h vertical synchronization pulse interval vout (odd field) vout (even field) vsync hsync (odd field) hsync (even field) 50% 50% 50% 50% 50% 50% figure 6. vout, vsync , and hsync timing (pal, external sync mode)
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 15 t vsf-vout t vsr-vout 1/2h vertical synchronization pulse interval vout (odd field) vout (even field) vsync hsync (odd field) hsync (even field) 50% 50% 50% 50% 50% 50% figure 7. vout, vsync , and hsync timing (pal, internal sync mode)
max7456 single-channel monochrome on-screen display with integrated eeprom 16 ______________________________________________________________________________________ vout hsync t vout-hsf t vout-hsr 50% 50% figure 8. vout, and hsync horizontal sync timing (ntsc and pal, external sync mode) vout hsync t hsf-vout t hsr-vout 50% 50% figure 9. vout and hsync horizontal sync timing (ntsc and pal, internal sync mode)
character memory (nvm) the character memory is a 256-row x 64-byte wide nonvolatile memory (nvm) that stores the characters or graphic images, and is factory preloaded with the char- acters shown in figure 12. the content of the character memory is user-programmable through the spi-com- patible serial interface. each row contains the descrip- tion of a single osd character. each character consists of 12 horizontal x 18 vertical pixels where each pixel is represented by 2 bits of data having three states: white, black, or transparent. thus, each character requires 54 bytes of pixel data (figure 11). the nvm requires reading and writing a whole charac- ter (64 bytes) at a time. this is enabled by an additional row of memory called the shadow ram. the 64-byte temporary shadow ram contains all the pixel data of a selected character (cmah[7:0]) and is used as a buffer for read and write operations to the nvm (figure 13). accessing the nvm is always through the shadow ram, and is thus a two-step process. to write a char- acter to the nvm, the user first fills the shadow ram using 54 8-bit spi write operations, and then executes a single shadow ram write command. similarly, read- ing a character? pixel values requires first reading a character? pixel data into the shadow ram, and then reading the desired pixel data from the shadow ram to the spi port. max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 17 display memory (two, 256 x 16-bit srams) 0 address (8 bit) l b c l b c b l k b l k i n v i n v l b c b l k i n v 479 29 display area (16 rows x 30 characters) 0 29 450 479 character attribute bit definitions: lbc = local background control blk = blink control inv = invert control x = don't care character memory address low (cmal) 0 pixel data arrangement in character memory (nvm) 256 rows x 64 bytes eeprom 0 1 2 515253 6162 63 012 51 52 53 61 62 63 12 pixels 4 pixel values (1 byte) (see figure 11 for pixel map) character data usage (12 x 18 pixels) 012 51 52 53 18 pixels 2-bit pixel definitions: 00 = black, opaque 10 = white, opaque x1 = transparent (external sync mode) or gray (internal sync mode) display memory address (dmah, dmal) display memory address (dmah, dmal) address (8 bit) address (8 bit) 30 59 unused memory x xxxx x xxxx x xxxx character address (ca) character attribute 255 0 54 54 53 54 character data character memory address high (cmah) character data arrangement in display memory (sram) 480 rows x 2 bytes sram 63 figure 10. definitions of various parameters
max7456 single-channel monochrome on-screen display with integrated eeprom 18 ______________________________________________________________________________________ 0 0, 1, 2 1 3, 4, 5 2 6, 7, 8 3 9, 10, 11 4 12, 13, 14 5 15, 16, 17 6 18, 19, 20 7 21, 22, 23 8 24, 25, 26 9 27, 28, 29 10 30, 31, 32 11 33, 34, 35 12 36, 37, 38 13 39, 40, 41 14 42, 43, 44 15 45, 46, 47 16 48, 49, 50 17 51, 52, 53 00 = black character memory address low cmal[5:0] 2-bit pixel definition: [5, 4] [3, 2] 10 = white x = don't care x1 = transparent (external sync mode) or gray (internal sync mode) [x, y] [x, y] 7 [7, 6] [5, 4] [3, 2] [7, 6] [5, 4] [7, 6] [x, y] pixel column number pixel row number [1, 0] [5, 4] [3, 2] [1, 0] [7, 6] 0 cdmi [5, 4] cdmi [3, 2] 123456 cdmi [7, 6] cdmi [1, 0] [7, 6] 8 9 10 11 [5, 4] [3, 2] [7, 6] [5, 4] [3, 2] [7, 6] [5, 4] [3, 2] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [5, 4] [3, 2] [1, 0] [1, 0] [5, 4] [3, 2] [1, 0] [7, 6] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [7, 6] [5, 4] [7, 6] [5, 4] [3, 2] [7, 6] [5, 4] [3, 2] [1, 0] [1, 0] [3, 2] [1, 0] [7, 6] [5, 4] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [5, 4] [3, 2] [1, 0] [1, 0] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [1, 0] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [5, 4] [3, 2] [1, 0] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [1, 0] [5, 4] [3, 2] [1, 0] [7, 6] [7, 6] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [1, 0] [7, 6] [5, 4] [3, 2] [7, 6] [5, 4] [3, 2] [5, 4] [3, 2] [5, 4] [3, 2] [1, 0] [7, 6] [7, 6] [5, 4] [3, 2] [1, 0] [1, 0] [1, 0] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [1, 0] [7, 6] [7, 6] [5, 4] [3, 2] [7, 6] [7, 6] [5, 4] [3, 2] [1, 0] [3, 2] [5, 4] [3, 2] [1, 0] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [7, 6] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [1, 0] [7, 6] [5, 4] [3, 2] [3, 2] [1, 0] [7, 6] [5, 4] figure 11. character data usage (pixel map)
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 19 ca[3:0], cmah[3:0] ca[7:4], cmah[7:4] figure 12. character address map (default character set)
max7456 on-screen display (osd) generator the osd generator sets each pixel amplitude based on the content of the character memory and row brightness registers (rb0?b15). osd insertion mux the osd insertion mux selects between an osd pixel and the input video signal. the osd image sharpness is controlled by the osd rise and fall time bits, and the osd insertion mux switching time bits, found in the osd insertion mux (osdm) register. this register con- trols the trade-off between osd image sharpness and crosscolor/crossluma artifacts. lower time settings pro- duce sharper pixels, but potentially greater crosscol- or/crossluma artifacts. the optimum setting depends on the requirements of the application and, therefore, can be set by the user. video-driver output the max7456 includes a video-driver output with a gain of 2. the driver has a maximum of 2.4v p-p output swing and a 6mhz large signal bandwidth ( 0.2db attenuation). the driver output is capable of driving two 150 ? standard video loads. sag correction sag correction is a means of reducing the electrical and physical size of the output coupling capacitor while achieving acceptable line-time distortion. sag correc- tion refers to the low frequency compensation of the highpass filter formed by the 150 ? load of a back-ter- minated coaxial cable and the output coupling capaci- tor. this breakpoint must be low enough in frequency to pass the vertical sync interval (< 25hz for pal and < 30hz for ntsc) to avoid field tilt. traditionally, the breakpoint is made < 5hz, and the coupling capacitor must be very large, typically > 330?. the max7456 reduces the value of this capacitor, replacing it with two smaller capacitors (c out and c sag ), substantially reducing the size and cost of the coupling capacitors while achieving acceptable line-time distortion (table 2). connect sag to vout if not used. serial interface the spi-compatible serial interface programs the oper- ating modes and osd data. read capability permits write verification and reading the status (stat), display memory data out (dmdo), and character memory data out (cmdo) registers. read and write operations the max7456 supports interface clocks (sclk) up to 10mhz. figure 15 illustrates writing data and figure 16 illustrates reading data from the max7456. bring cs low to enable the serial interface. data is clocked in at sdin on the rising edge of sclk. when cs transitions high, data is latched into the input register. if cs goes high in the middle of a transmission, the sequence is aborted (i.e., data does not get written into the regis- ters). after cs is brought low, the device waits for the first byte to be clocked into sdin to identify the type of data transfer being executed. the spi commands are 16 bits long with the 8 most sig- nificant bits (msbs) representing the register address and the 8 least significant bits (lsbs) representing the data (figures 15 and 16). there are two exceptions to this arrangement: 1) auto-increment write mode used for display memory access is a single 8-bit operation (figure 21). when performing the auto-increment write for the display memory, the 8-bit address is internally generated, and only 8-bit data is required at the serial interface. 2) reading character data from the display memory, when in 16-bit operation mode, is a 24-bit operation (8-bit address plus 16-bit data). see figure 20. single-channel monochrome on-screen display with integrated eeprom 20 ______________________________________________________________________________________ 0 . . . . . . . . . . . address decoder nvm array (256 rows x 64 bytes) 64-byte shadow ram cmah [7:0] cmdi [7:0] cmdo [7:0] 63 0 . . . . . . . . . . . . . . . . . . . . . . . 255 cmal [5:0] figure 13. nvm structure c out (f) c sag (f) line-time distortion (% typ) 470 0.2 100 0.4 100 22 0.3 47 47 0.3 22 22 0.4 10 10 0.6 table 2. sag-correction capacitor values
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 21 t csh0 t css0 t dh t ch t cl t css1 t csh1 t csw t cp cs sclk sdin sdout t do1 t do2 t do3 t do4 t ds figure 14. detailed serial-interface timing cs sclk sdin msb lsb 12345678 9 10 11 12 13 14 15 16 d7 d6 d5 d4 d3 d2 d1 d0 a6 a5 a4 a3 a2 a1 a0 0 figure 15. write operation cs sclk sdin msb msb 12345678 9 10 11 12 13 14 15 16 d7 d6 d5 d4 d3 d2 d1 d0 x a6 a5 a4 a3 a2 a1 a0 1 sdout lsb lsb figure 16. read operation cs sclk sdin msb lsb 12345678 9 10 11 12 13 14 15 16 00000111 l b c b l k i n v 00000 figure 17. writing character attribute byte in 8-bit operation mode cs sclk sdin msb msb 12345678 9 10 11 12 13 14 15 16 l b c b l k i n v 0 0 0 0 0 x 10 11xxxx sdout lsb lsb figure 18. reading character attribute byte in 8-bit operation mode
max7456 resets power-on reset the max7456? power-on reset circuitry (por) pro- vides an internal reset signal that is active after the sup- ply voltage has stabilized. the internal reset signal resets all registers to their default values and clears the display memory. the register reset process requires 100?, and to avoid unexpected results, read/write activity is not allowed during this interval. the display memory is reset, and the osd is enabled typically 50ms after the supply voltage has stabilized and a sta- ble 27mhz clock is available. the user should avoid spi operations during this time to avoid unexpected results. after 50ms (typical), stat[6] can be polled to verify that the reset sequence is complete (figure 22). single-channel monochrome on-screen display with integrated eeprom 22 ______________________________________________________________________________________ cs sclk sdin msb lsb 12345678 9 10 11 12 13 14 15 16 00000111 c a 7 c a 6 c a 5 c a 4 c a 3 c a 2 c a 1 c a 0 figure 19. writing character address byte in 8-bit and 16-bit operation modes cs sclk sdin msb 12345678 12345678 9 10 11 12 13 14 15 16 c a 7 c a 6 c a 5 c a 4 c a 3 c a 2 c a 1 c a 0 x 10 11xxxx sdout lsb msb l b c b l k i n v 0 0 0 00 lsb figure 20. reading character address and character attribute bytes in 16-bit operation mode cs sclk sdin msb lsb 12345678 d7 d6 d5 d4 d3 d2 d1 d0 figure 21. write operation in auto-increment mode
software reset the max7456 features a software reset bit (vm0[1]) that, when set high, clears the display memory and resets all registers to their default values except the osd black level register (osdbl). after 100? (typi- cal), stat[6] can be polled to verify that the reset process is complete. hardware reset the max7456 provides a hardware reset input ( reset ) that functions the same as the por. all registers are reset to their default values and are not accessible for reading/writing when reset is driven low. the resetting process requires a 50ms wide reset pulse, and no other activities are allowed during this interval. all spi registers are reset to their default values 100? after the rising edge of reset . the display memory is reset to its default value of 00h in all locations 20? after the ris- ing edge of reset . reset takes precedence over the software reset bit. after reset has been deasserted, stat[6] can be polled to verify that the reset sequence is complete. max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 23 supply voltage xtal oscillator 50ms 4.75v 0v spi register reset 100 s 50ms display memory clear 20 s power on power stable clock stable power-on reset start por default state figure 22. power-on reset sequence
max7456 max7456 register description access to all max7456 operations, including display- memory and character-memory access, are through the spi registers listed in table 3. there is no direct access to the display and character memories through the spi port. see the applications information section for step-by-step descriptions of the spi operations needed to access the memories. the register format used in this data sheet is register_name [bit_numbers]. for example, bit 1 in video mode 0 register is written as vm0[1]. single-channel monochrome on-screen display with integrated eeprom 24 ______________________________________________________________________________________ table 3. register map write address read address register name register description 00h 80h vm0 video mode 0 01h 81h vm1 video mode 1 02h 82h hos horizontal offset 03h 83h vos vertical offset 04h 84h dmm display memory mode 05h 85h dmah display memory address high 06h 86h dmal display memory address low 07h 87h dmdi display memory data in 08h 88h cmm character memory mode 09h 89h cmah character memory address high 0ah 8ah cmal character memory address low 0bh 8bh cmdi character memory data in 0ch 8ch osdm osd insertion mux 10h 90h rb0 row 0 brightness 11h 91h rb1 row 1 brightness 12h 92h rb2 row 2 brightness 13h 93h rb3 row 3 brightness 14h 94h rb4 row 4 brightness 15h 95h rb5 row 5 brightness 16h 96h rb6 row 6 brightness 17h 97h rb7 row 7 brightness 18h 98h rb8 row 8 brightness 19h 99h rb9 row 9 brightness 1ah 9ah rb10 row 10 brightness 1bh 9bh rb11 row 11 brightness 1ch 9ch rb12 row 12 brightness 1dh 9dh rb13 row 13 brightness 1eh 9eh rb14 row 14 brightness 1fh 9fh rb15 row 15 brightness 6ch ech osdbl osd black level axh stat status bxh dmdo display memory data out cxh cmdo character memory data out x = don? care.
video mode 0 register (vm0) write address = 00h, read address = 80h. read/write access: unrestricted. to write to this register, the following conditions must be met: 1) stat[5] = 0, the character memory (nvm) is not busy. 2) dmm[2] = 0, the display memory (sram) is not in the process of being cleared. max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 25 bit default function 7 0 don? care 60 video standard select 0 = ntsc 1 = pal 5, 4 00 sync select mode (table 1) 0x = autosync select (external sync when los = 0 and internal sync when los = 1) 10 = external 11 = internal 30 enable display of osd image 0 = off 1 = on 20 vertical synchronization of on-screen data 0 = enable on-screen display immediately 1 = enable on-screen display at the next vsync 10 software reset bit when this bit is set, all registers are set to their default values and the display memory is cleared. when a stable 27mhz clock is present, this bit is automatically cleared internally after typically 100?. the user does not need to write a 0 afterwards. spi operations should not be performed during this time or unpredictable results may occur. the status of the bit can be checked by reading this register after typically 100?. this register is not accessible for writing until the display memory clear operation is finished (typically 20?). 00 video buffer enable 0 = enable 1 = disable (vout is high impedance) x = don? care.
max7456 single-channel monochrome on-screen display with integrated eeprom 26 ______________________________________________________________________________________ video mode 1 register (vm1) write address = 01h, read address = 81h. read/write access: unrestricted. bit default function 70 background mode (see table 4) 0 = the local background control bit (see dmm[5] and dmdi[7]) sets the state of each character background. 1 = sets all displayed background pixels to gray. the gray level is specified by bits vm1[6:4] below. this bit overrides the local background control bit. note: in internal sync mode, the background mode bit is set to 1. 6, 5, 4 100 background mode brightness (% of osd white level) 000 = 0% 001 = 7% 010 = 14% 011 = 21% 100 = 28% 101 = 35% 110 = 42% 111 = 49% 3, 2 01 blinking time (bt) 00 = 2 fields (33ms in ntsc mode, 40ms in pal mode) 01 = 4 fields (67ms in ntsc mode, 80ms in pal mode) 10 = 6 fields (100ms in ntsc mode, 120ms in pal mode) 11 = 8 fields (133ms in ntsc mode, 160ms in pal mode) 1, 0 11 blinking duty cycle (on : off) 00 = bt : bt 01 = bt : (2 x bt) 10 = bt : (3 x bt) 11 = (3 x bt) : bt horizontal offset register (hos) write address = 02h, read address = 82h. read/write access: unrestricted (figure 23). bit default function 7, 6 00 don? care 5? 10 0000 horizontal position offset (osd video is not inserted into the horizontal blanking interval) 00 0000 = farthest left (-32 pixels) 10 0000 = no horizontal offset 11 1111 = farthest right (+31 pixels)
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 27 vertical offset register (vos) write address = 03h, read address = 83h. read/write access: unrestricted (figure 23). bit default function 7, 6, 5 000 don? care 4? 1 0000 vertical position offset (osd video can be vertically shifted into the vertical blanking lines) 0 0000 = farthest up (+16 pixels) 1 0000 = no vertical offset 1 1111 = farthest down (-15 pixels) horizontal position offset vertical position offset display area: ntsc: 13 rows x 30 columns pal: 16 rows x 30 columns ntsc: 234 lines pal: 288 lines hsync vsync row no. 0 15 360 pixels figure 23. character display area
max7456 single-channel monochrome on-screen display with integrated eeprom 28 ______________________________________________________________________________________ display memory mode register (dmm) write address = 04h, read address = 84h. read/write access: unrestricted. to write to this register, the following condition must be met: dmm[2] = 0, the display memory is not in the process of being cleared. bit default function 7 0 don? care 60 operation mode selection 0 = 16-bit operation mode the 16-bit operation mode increases the speed at which the display memory can be updated. when writing to the display memory, the attribute byte is not entered through the spi-compatible interface. it is entered automatically by copying dmm[5:3] to a character? attribute byte when a new character is written, thus reducing the number of spi write operations per character from two to one (figure 19). when in this mode, all characters written to the display memory have the same attribute byte. this mode is useful because successive characters commonly have the same attribute. this mode is distinct from the 8-bit operation mode where a character attribute byte must be written each time a character address byte is written to the display memory (see table 5). when reading data from the display memory, both the character address byte and character attribute byte are transferred with the spi-compatible interface (figure 18). 1 = 8-bit operation mode the 8-bit operation mode provides maximum flexibility when writing characters to the display memory. this mode enables writing individual character attribute bytes for each character (see table 5). when writing to the display memory, dmah[1] = 0 directs the data to the character address byte and dmah[1] = 1 directs the character attributes byte to the data. this mode is distinct from the 16-bit operation mode where the attribute bits are automatically copied from dmm[5:3] when a character is written. 50 local background control bit, lbc (see table 4) applies to characters written in 16-bit operating mode. 0 = sets the background pixels of the character to the video input (vin) when in external sync mode. 1 = sets the background pixels of the character to the background mode brightness level defined by vm1[6:4] in external or internal sync mode. note: in internal sync mode, the local background control bit behaves as if it is set to 1. 40 blink bit, blk applies to characters written in 16-bit operating mode. 0 = blinking off 1 = blinking on note: blinking rate and blinking duty cycle data in the video mode 1 (vm1) register are used for blinking control. in external sync mode: when the character is not displayed, vin is displayed. in internal sync mode: when the character is not displayed, background mode brightness is displayed (see vm1[6:4]). 30 invert bit, inv applies to characters written in 16-bit operating mode (see figure 24). 0 = normal (white pixels display white, black pixels display black) 1 = invert (white pixels display black, black pixels display white)
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 29 display memory mode register (dmm) (continued) bit default function 20 clear display memory 0 = inactive 1 = clear (fill all display memories with zeros) note: this bit is automatically cleared after the operation is completed (the operation requires 20?). the user does not need to write a 0 afterwards. the status of the bit can be checked by reading this register. this operation is automatically performed: a) on power-up b) immediately following the rising edge of reset c) immediately following the rising edge of cs after vm0[1] has been set to 1 10 vertical sync clear valid only when clear display memory = 1, (dmm[2] = 1) 0 = immediately applies the clear display-memory command, dmm[2] = 1 1 = applies the clear display-memory command, dmm[2] = 1, at the next vsync time 00 auto-increment mode auto-increment mode increases the speed at which the display memory can be written by automatically incrementing the character address for each successive character written. this mode reduces the number of spi commands, and thus the time needed to write a string of adjacent characters. this mode is useful when writing strings of characters written from left-to-right, top-to- bottom, on the display (see table 5). 0 = disabled 1 = enabled when this bit is enabled for the first time, data in the display memory address (dmah[0] and dmal[7:0]) registers are used as the starting location to which the data is written. when performing the auto-increment write for the display memory, the 8-bit address is internally generated, and therefore only 8-bit data is required by the spi-compatible interface (figure 21). the content is to be interpreted as a character address byte if dmah[1] = 0 or a character attribute byte if dmah[1] = 1. this mode is disabled by writing the escape character 1111 1111. if the clear display memory bit is set, this bit is reset internally.
max7456 single-channel monochrome on-screen display with integrated eeprom 30 ______________________________________________________________________________________ invert bit dmm[3] external sync mode and local background control bit (lbc) = 0 internal sync mode or local background control bit (lbc) = 1 0 1 figure 24. character attribute bit examples: invert and local background control
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 31 table 4. character background control sync mode background mode, vm1[7] local background control bit, lbc dmm[5], dmdi[7] character background pixel 0 0 input video 0 1 gray external 1 x gray internal x x gray x = don? care. display memory address high register (dmah) write address = 05h, read address = 85h. read/write access: unrestricted. to write to this register, the following condition must be met: dmm[2] = 0, the display memory is not in the process of being cleared. bit default function 7? 0000 00 don? care 10 byte selection bit this bit is valid only when in the 8-bit operation mode (dmm[6] = 1). 0 = character address byte is written to or read (dmdi[7:0] contains the character address byte). 1 = character attribute byte is written to or read (dmdi[7:0] contains the character attribute byte). 00 display memory address bit 8 this bit is the msb of the display-memory address. the display-memory address sets the location of a character on the display (figure 10). the lower order 8 bits of the display-memory address is found in dmal[7:0]. display memory address low register (dmal) write address = 06h, read address = 86h. read/write access: unrestricted. to write to this register, the following condition must be met: dmm[2] = 0, the display memory is not in the process of being cleared. bit default function 7? 0000 0000 display memory address bits 7? this byte is the lower 8 bits of the display-memory address. the display-memory address sets the location of a character on the display (figure 10). the msb of the display-memory address is dmah[0].
max7456 single-channel monochrome on-screen display with integrated eeprom 32 ______________________________________________________________________________________ display memory data in register (dmdi) write address = 07h, read address = 87h. read/write access: unrestricted. to write to this register, the following condition must be met: dmm[2] = 0, the display memory is not in the process of being cleared. bit default function 7? 0000 0000 character address or character attribute byte to be stored in the display memory. 8-bit operation mode (dmm[6] = 1) if dmah[1] = 0, the content is to be interpreted as a character address byte, where bits 7? = character address bits, ca[7:0] (figure 12). if dmah[1] = 1, the content is to be interpreted as a character attribute byte where bit 7 = local background control bit, lbc (figure 24 and table 4) bit 6 = blink bit, blk bit 5 = invert bit, inv (see figure 24) bit 4? = 0 (the lbc, blk, and inv bits are described in the display memory mode register.) 16-bit operation mode (dmm[6] = 0) the content is always interpreted as a character address byte where bits 7? = ca[7:0] (figure 12). auto-increment mode (dmm[0] = 1) the character address ca[7:0] = ffh is reserved for use as an escape character that terminates the auto-increment mode. therefore, the character located at address ffh is not available for writing to the display memory when in auto-increment mode. in all other modes, character ffh is available.
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 33 character memory mode register (cmm) write address = 08h, read address = 88h. read/write access: unrestricted. to write to this register, the following conditions must be met: 1) stat[5] = 0, the character memory (nvm) is not busy. 2) vm0[3] = 0, the osd is disabled. x = don? care. bit default function 7? 0000 0000 only whole characters (54 bytes) can be written to or read from the nonvolatile character memory (nvm) at one time. this is done through the (64 byte) shadow ram (figure 13). the shadow ram is accessed through the spi port one byte at a time. the shadow ram is written to and read from nvm by the following procedures: writing to nvm 1010 xxxx = write to nvm array from shadow ram. the 64 bytes from shadow ram are written to the nvm array at the character-memory address location (cmah, cmal) (figure 13). the character memory is busy for approximately 12ms during this operation. during this time, stat[5] is automatically set to 1. the character memory mode register is cleared and stat[5] is reset to 0 after the write operation has been completed. the user does not need to write zeros afterwards. reading from nvm 0101 xxxx = read from nvm array into shadow ram. the 64 bytes corresponding to the character-memory address (cmah, cmal) are read from the nvm array into the shadow ram (figure 13). the character memory is busy for approximately 0.5? during this operation. the cmm register is cleared after the operation is completed. the user does not need to write zeros afterwards. during this time, stat[5] is automatically set to 1. stat[5] is reset to 0 when the read operation has been complete. if the display has been enabled (vm0[3] = 1) or the character memory is busy (stat[5] = 1), nvm read/write operation commands are ignored and the corresponding registers are not updated. however, all the registers can be read at any time. for all the character-memory operations, the character address is formed with character memory address high (cmah[7:0]) and character memory address low (cmal[7:0]) register bits (figures 11, 12, and 13).
max7456 single-channel monochrome on-screen display with integrated eeprom 34 ______________________________________________________________________________________ character memory address high register (cmah) write address = 09h, read address = 89h. read/write access: unrestricted. to write to this register, the following conditions must be met: 1) stat[5] = 0, the character memory (nvm) is not busy. 2) vm0[3] = 0, the osd is disabled. bit default function 7? 0000 0000 character memory address bits these 8 bits point to a character in the character memory (256 characters total in nvm) (figures 10 and 12). character memory address low register (cmal) write address = 0ah, read address = 8ah. read/write access: unrestricted. to write to this register, the following conditions must be met: 1) stat[5] = 0, the character memory (nvm) is not busy. 2) vm0[3] = 0, the osd is disabled. bit default function 7, 6 00 don? care 5? 00 0000 character memory address bits these 6 bits point to one of the 64 bytes (only 54 used) that represent a 4-pixel group in the character (figures 10 and 11). character memory data in register (cmdi) write address = 0bh, read address = 8bh. read/write access: unrestricted. to write to this register, the following conditions must be met: 1) stat[5] = 0, the character memory (nvm) is not busy. 2) vm0[3] = 0, the osd is disabled. bit default function 7, 6 na leftmost pixel. 00 = black, 10 = white, 01 or 11 = transparent (see figure 11) 5, 4 na left center pixel. 00 = black, 10 = white, 01 or 11 = transparent (see figure 11) 3, 2 na right center pixel. 00 = black, 10 = white, 01 or 11 = transparent (see figure 11) 1, 0 na rightmost pixel. 00 = black, 10 = white, 01 or 11 = transparent (see figure 11) na = not applicable.
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 35 osd insertion mux register (osdm) write address = 0ch, read address = 8ch. read/write access: unrestricted. bit default function 7, 6 00 don? care 5, 4, 3 011 osd rise and fall time?ypical transition times between adjacent osd pixels 000: 20ns (maximum sharpness/maximum crosscolor artifacts ) 001: 30ns 010: 35ns 011: 60ns 100: 80ns 101: 110ns (minimum sharpness/minimum crosscolor artifacts) 2, 1, 0 011 osd insertion mux switching time?ypical transition times between input video and osd pixels 000: 30ns (maximum sharpness/maximum crosscolor artifacts ) 001: 35ns 010: 50ns 011: 75ns 100: 100ns 101: 120ns (minimum sharpness/minimum crosscolor artifacts) row n brightness register (rb0?b15) address = 10h + row number; write address = 10h through 1fh, read address = 90h through 9fh, read/write access: unrestricted. top row number is 0. bottom row number is 13 in ntsc mode and 15 in pal mode (see figure 23). bit default function 7? 0000 don? care 3, 2 00 character black level ?ll the characters in row n use these brightness levels for the black pixel, in % of osd white level. 00 = 0% 01 = 10% 10 = 20% 11 = 30% 1, 0 01 character white level ?ll the characters in row n use these brightness levels for the white pixel, in % of osd white level. 00 = 120% 01 = 100% 10 = 90% 11 = 80%
max7456 single-channel monochrome on-screen display with integrated eeprom 36 ______________________________________________________________________________________ osd black level register (osdbl) write address = 6ch, read address = ech. read/write access: this register contains 4 factory-pre- set bits [3:0] that must not be changed. therefore, when changing bit 4, first read this register, modify bit 4, and then write back the updated byte. bit default function 7? 000 don? care 41 osd image black level control this bit enables the alignment of the osd image black level with the input image black level at vout. always enable this bit following power-on reset to ensure the correct osd image brightness. 0 = enable automatic osd black level control 1 = disable automatic osd black level control 0? xxxx these bits are factory preset. to ensure proper operation of the max7456, do not change the values of these bits. xxxx = factory preset?an be any one of the 16 possible values. this value is permanently stored in the max7456 and will always be restored to the factory preset value following power-on reset or hardware reset. status register (stat) read address = axh. read/write access: read only. bit default function 7 na don? care 6na reset m od e 0 = c l ear w hen p ow er - up r eset m od e i s com p l ete. o ccur s 50m s ( typ ) fol l ow i ng stab l e v d d ( fi g ur e 22) 1 = s et w hen i n p ow er - up r eset m od e 5na character memory status 0 = available to be written to or read from 1 = unavailable to be written to or read from 4na vsync output level 0 = active during vertical sync time 1 = inactive otherwise 3na hsync output level 0 = active during horizontal sync time 1 = inactive otherwise 2na loss-of-sync (los) 0 = sync active. asserted after 32 consecutive input video lines. 1 = no sync. asserted after 32 consecutive missing input video lines. 1na 0 = ntsc signal is not detected at vin 1 = ntsc signal is detected at vin 0na 0 = pal signal is not detected at vin 1 = pal signal is detected at vin na = not applicable. x = don? care.
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 37 display memory data out register (dmdo) read address = bxh. read/write access: read only. to write to this register the following condition must be met: dmm[2] = 0, the display memory is not in the process of being cleared. bit default function 7? na character address or character attribute byte to be read from the display memory. 8-bit operation mode (dmm[6] = 1): if dmah[1] = 0, the content is to be interpreted as a character address byte, where bits 7? = character address bits, ca[7:0] (figure 12) if dmah[1] = 1, the content is to be interpreted as a character attribute byte where bit 7 = local background control bit, lbc (see figure 24 and table 4) bit 6 = blink bit, blk bit 5 = invert bit, inv (see figure 24) bit 4? = 0 the lbc, blk, and inv bits are described in the display memory mode register. 16-bit operation mode (dmm[6] = 0): the content is to be interpreted as a character address byte, where bits 7? = ca[7:0] (see figure 12) followed by a character attribute byte, where bit 7 = 0 bit 6 = local background control bit, lbc (see figure 24 and table 4) bit 5 = blink bit, blk bit 4 = invert bit, inv (see figure 24) bit 3? = 0 the lbc, blk, and inv bits are described in the display memory mode register. na = not applicable. x = don? care. character memory data out register (cmdo) read address = cxh. read/write access: read only. to write to this register, the following conditions must be met: 1) stat[5] = 0, the character memory (nvm) is not busy. 2) vm0[3] = 0, the osd is disabled. bit default function 7, 6 na leftmost pixel. 00 = black, 10 = white, 01 or 11 = transparent (see figure 11) 5, 4 na left center pixel. 00 = black, 10 = white, 01 or 11 = transparent (see figure 11) 3, 2 na right center pixel. 00 = black, 10 = white, 01 or 11 = transparent (see figure 11) 1, 0 na rightmost pixel. 00 = black, 10 = white, 01 or 11 = transparent (see figure 11) na = not applicable. x = don? care.
max7456 single-channel monochrome on-screen display with integrated eeprom 38 ______________________________________________________________________________________ applications information character-memory operation only whole characters (54 bytes of pixel data) can be written to or read from the nvm character memory at one time. this is done through the (64 byte) shadow ram (see figure 13). the shadow ram is accessed by the spi port one byte at a time. the shadow ram is written to and read from the nvm by a single spi command. steps for writing character bytes into the nvm character memory writing a new character: 1) write vm0[3] = 0 to disable the osd image display. 2) write cmah[7:0] = xxh to select the character (0?55) to be written (figures 10 and 13). 3) write cmal[7:0] = xxh to select the 4-pixel byte (0?3) in the character to be written (figures 10 and 13). 4) write cmdi[7:0] = xxh to set the pixel values of the selected part of the character (figures 11 and 13). 5) repeat steps 3 and 4 until all 54 bytes of the char- acter data are loaded into the shadow ram. 6) write cmm[7:0] = 1010xxxx to write to the nvm array from the shadow ram (figure 13). the char- acter memory is busy for approximately 12ms dur- ing this operation. stat[5] can be read to verify that the nvm writing process is complete. 7) write vm0[3] = 1 to enable the osd image display. modifying an existing character: 1) write vm0[3] = 0 to disable the osd image display. 2) write cmah[7:0] = xxh to select the character (0?55) to be modified (figures 10 and 13). 3) write cmm[7:0] = 0101xxxx to read character data from the nvm to the shadow ram (figure 13). 4) write cmal[7:0] = xxh to select the 4-pixel byte (0?3) in the character to be modified (figures 10 and 13). 5) read cmdo[7:0] = xxh to read the byte of 4-pixel data to be modified (figures 11 and 13). 6) modify the byte of 4-pixel data as desired. 7) write cmdi[7:0] = xxh to write the modified byte of 4-pixel data back to the shadow ram (figures 11 and 13). 8) repeat steps 4 through 7 as needed until all pixels have been loaded into the shadow ram. 9) write cmm[7:0] = 1010xxxx to write the shadow ram data to the nvm (figure 13). the character memory is busy for typically 12ms during this oper- ation. stat[5] can be read to verify that the nvm writing process is complete. 10) write vm0[3] =1 to enable the osd image display. steps for reading character bytes from character memory 1) write vm0[3] = 0 to disable the osd image. 2) write cmah[7:0] = xxh to select the character (0?55) to be read (figures 10 and 13). 3) write cmm[7:0] = 0101xxxx to read the character data from the nvm to the shadow ram (figure 13). 4) write cmal[7:0] = xxh to select the 4-pixel byte (0?3) in the character to be read (figures 10 and 13). 5) read cmdo[7:0] = xxh to read the selected 4-pixel byte of data (figures 11 and 13). 6) repeat steps 4 and 5 to read other bytes of 4-pixel data. 7) write vm0[3] = 1 to enable the osd image display. display-memory operation the following two steps enable viewing of the osd image. these steps are not required to read from or write to the display memory: 1) write vm0[3] = 1 to enable the display of the osd image. 2) write osdbl[4] = 0 to enable automatic osd black level control. this ensures the correct osd image brightness. this register contains 4 factory-preset bits [3:0] that must not be changed. therefore, when changing bit 4, first read osdbl[7:0], modify bit 4, and then write back the updated byte. steps for clearing display memory write dmm[2] = 1 to start the clear display-memory operation. this operation typically takes 20?. the display memory mode register cannot be written to again until the clear operation is complete. dmm[2] is automatically reset to zero upon completion. steps for writing to display memory in 8-bit mode the 8-bit operation mode provides maximum flexibility when writing characters to the display memory. this mode enables writing individual character attribute bytes for each character (see table 5). this mode is distinct from the 16-bit operation mode where the character attribute byte is automatically copied from dmm[5:3] when a character is written (figure 19). write dmm[6] = 1 to select the 8-bit operation mode.
writing the character address byte to the display memory: 1) write dmah[1] = 0 to write a character address byte. 2) write dmah[0] = x to select the msb and dmal[7:0] = xxh to select the lower order bits of the address where the character data is to be writ- ten. this address determines the location of the character on the display (see figure 10). 3) write the character address byte (ca[7:0]) to be written to the display memory to dmdi[7:0] (see figures 10, 12, and 19). writing the character attribute byte to the display memory: 1) write dmah[1] = 1 to write a character attribute byte. 2) write dmah[0] = x to select the msb and dmal[7:0] = xxh to select the lower order bits of the address where the character data is to be writ- ten. this address determines the location of the character on the display (figure 10). 3) write the character attribute byte to be written to the display memory to dmdi[7:0] (see figures 10 and 19). steps for writing to display memory in 16-bit mode the 16-bit operation mode increases the speed at which the display memory can be updated. this is done by automatically copying dmm[5:3] to a character? attribute byte when a new character is writ- ten, thus reducing the number of spi write operations per character from two to one (figure 19). when in this mode, all characters written to the display memory have the same attribute byte. this mode is useful because successive characters commonly have the same attribute. this mode is distinct from the 8-bit operation mode where a character attribute byte must be written each time a character address byte is writ- ten to the display memory (see table 5). 1) write dmm[6] = 0 to select the 16-bit operation mode. 2) write dmm[5:3] = xxx to set the local background control (lbc), blink (blk), and invert (inv) attribute bits that will be applied to all characters written to the display memory while in the 16-bit operation mode. 3) write dmah[0] = x to select the msb and dmal[7:0] = xxh to select the lower order bits of the address where the character data is to be written. this address determines the location of the charac- ter on the display (see figure 10). 4) write the character address byte (ca[7:0]) to be written to the display memory into dmdi[7:0]. it will be stored along with a character attribute byte derived from dmm[5:3] (figures 12 and 19). steps for writing to display memory in auto-increment mode auto-increment mode increases the speed at which the display memory can be written by automatically incre- menting the character address for each successive character written. this mode is useful when writing strings of characters written from left-to-right and top- to-bottom on the display. this mode reduces the num- ber of spi commands (see table 5). when in 8-bit operating mode: 1) write dmm[0] = 1 to set the auto-increment mode. 2) write to dmm[6] = 1 to set the 8-bit operation mode. 3) write dmah[1] = 0 to select if a character address byte will be written or dmah[1] = 1 to select if a character attribute byte will be written. 4) write dmah[0] = x to select the msb and dmal[7:0] to select the lower order address bits, of the starting address for auto-increment operation. this address determines the location of the charac- ter on the display (see figures 10 and 21). 5) write to dmdi[7:0] to store character data (character address or character attribute bytes) to the current display-memory address. the display-memory address is automatically incremented following the write operation. subsequent characters are succes- sively written from left-to-right and top-to-bottom on the display (see figure 10). repeat until the final display- memory address is reached. 6) write dmdi[7:0] = ffh to terminate the auto-incre- ment mode. note that the character stored at ca[7:0] = ffh is not available for use when in auto- increment mode. when in 16-bit operating mode: 1) write dmm[0] = 1 to set the auto-increment mode. 2) write dmm[6] = 0 to set the 16-bit operation mode. 3) write dmm[5:3] = xxx to set the local background control (lbc), blink (blk), and invert (inv) attribute bits that will be applied to all characters. 4) write dmah[0] = x to select the msb and dmal[7:0] to select the lower order address bits, of the starting address for auto-increment operation. max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 39
max7456 this address determines the location of the charac- ter on the display (see figures 10 and 21). 5) write the character address byte (ca[7:0]) to be written to the display memory into dmdi[7:0]. it will be stored along with a character attribute byte derived from dmm[5:3] (see figure 19). the dis- play-memory address is automatically incremented following the write operation. repeat until the final display-memory address is reached. 6) write dmdi[7:0] = ffh to terminate the auto-incre- ment mode. note that the character stored at ca[7:0] = ffh is not available for use when in auto- increment mode. steps for reading from display memory in 8-bit mode 1) write dmm[6] = 1 to select the 8-bit operation mode. 2) write dmah[1] = 0 to read the character address byte or dmah[1] = 1 to read the character attribute byte. 3) write to dmah[0] to select the msb of the address where data must be read from (figure 10). 4) write to dmal[7:0] to select all the lower order bits, except for the msb, of the address where data must be read from (figure 10). 5) read dmdo[7:0] to read the data from the selected location in the display memory (figure 10). steps for reading from display memory in 16-bit mode 1) write dmm[6] = 0 to select the 16-bit operation mode. 2) write dmah[0] = x to select the msb and dmal[7:0] = xxh to select the lower order bits of the address where the character data is to be read. this address determines the location of the charac- ter on the display (see figure 10). 3) read dmdo[15:0] to read the character address byte and the character attribute byte from the selected location in the display memory. the first data byte is the character address (ca[7:0]), and the second byte contains the character attribute bits (figure 20). note that the bit positions of the character attribute byte when read, differ from when they are written. see the display memory data out register (dmdo) section and figure 20 for a description of the bit locations of the attribute bits when reading. note: if an internal display-memory read request occurs simultaneously with an spi display-memory operation, the internal read request is ignored, and the display of that character, during that field time, may appear to momentarily break up. see the synchronous osd updates section. synchronous osd updates the display of a character may momentarily appear to break up if an internal display-memory read request occurs simultaneously with an spi display-memory operation. momentary breakup of the osd image can be prevented by writing to the display memory during the vertical blanking interval. this can be achieved by using vsync as an interrupt to the host processor to initiate writing to the display memory. alternatively, the osd image can be synchronously disabled before writ- ing to the display memory and synchronously re- enabled afterwards (see vm0[3:2]). multiple osds with common clock application the max7456 provides a ttl clock output (clkout) capable of driving one clkin pin of another max7456. two or more max7456 parts can be driven using an external clock driver. this arrangement reduces the system cost by having only one crystal on one max7456 that supplies the clock signal to multiple max7456 parts (figure 25). single-channel monochrome on-screen display with integrated eeprom 40 ______________________________________________________________________________________ table 5. display-memory access modes and spi operations operating mode auto-increment mode disabled dmm[0] = 0 no. of read operations no. of write operations auto-increment mode enabled dmm[0] = 1 no. of write operations one-time setup 2 1 one-time setup 6 16-bit mode dmm[6] = 0 per character 3 3 per character 1 one-time setup 1 1 one-time setup 6 8-bit mode dmm[6] = 1 per character 6 6 per character 1
max7456 single-channel monochrome on-screen display with integrated eeprom ______________________________________________________________________________________ 41 28 27 26 25 24 23 22 21 20 19 18 17 16 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 max7456 sdin +5v 27mhz sdout +5v cvbs out1 sag pgnd reset hsync vsync dgnd clkin xfb clkout cs sdin sclk sdout los n.c. sclk cs1 cvbs in1 los1 vs1 hs1 n.c. n.c. n.c. n.c. n.c. agnd n.c. n.c. +5v 0.1 f c out 75 ? 75 ? 1k ? 1k ? 1k ? 0.1 f +5v 1k ? 1k ? 1k ? 0.1 f 0.1 f c sag c out c sag 28 27 26 25 24 23 22 21 20 19 18 17 16 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 max7456 +5v clock driver +5v cvbs out2 sag pgnd reset hsync vsync dvdd dgnd clkin xfb clkout cs sdin sclk sdout los n.c. cs2 cvbs in2 los2 vs2 hs2 n.c. n.c. n.c. n.c. n.c. agnd n.c. n.c. 0.1 f to other max7456 parts as needed vout pvdd vin avdd 75 ? 75 ? 0.1 f 0.1 f 0.1 f dvdd vout pvdd vin avdd + + figure 25. typical multiple osds with daisy-chained clock
max7456 single-channel monochrome on-screen display with integrated eeprom 42 ______________________________________________________________________________________ selecting a clock crystal choose a 27mhz parallel resonant, fundamental mode crystal. no external load capacitors are needed. all capacitors required for the pierce oscillator are includ- ed on-chip. power supply and bypassing the max7456 operates from three independent supply lines. each supply must be within a +4.75v to +5.25v voltage range. separate the digital power supply from the analog and video-driver supply lines to prevent high-frequency digital noise that may couple onto the video output. all three supplies should be at the same dc voltage. bypass each supply with a 0.1? capacitor to ground very close to the ic pins. there are no power-supply sequencing requirements for the device. layout concerns for best performance, make the vin and vout traces as short as possible. place all ac-coupling capacitors and 75 ? termination resistors close to the device with the resistors terminated to the solid analog ground plane. since the max7456 tssop package has an exposed pad (ep) underneath, do not run traces under the package to avoid possible short circuits. refer to the max7456 ev kit for an example of pcb layout. to aid heat dissipation, the ep should be connected to a similarly sized pad on the component side of the pcb. this pad should be connected through to the sol- der-side copper by several plated holes to conduct heat away from the device. the solder-side copper pad area should be larger than the ep area. it is recom- mended that the ep be connected to ground, but it is not required. do not use ep as the only ground connec- tion for the device. 28 27 26 25 24 23 22 21 20 19 18 17 16 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 n.c. n.c. vout sag pvdd pgnd n.c. vin avdd agnd reset hsync vsync n.c. n.c. n.c. los sdout sclk sdin cs clkout xfb clkin dgnd dvdd n.c. n.c. tssop top view max7456 + pin configuration chip information process: bicmos
max7456 single-channel monochrome on-screen display with integrated eeprom maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ____________________ 43 2007 maxim integrated products is a registered trademark of maxim integrated products, inc. package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .) tssop 4.4mm body.eps e 1 1 21-0108 package outline, tssop, 4.40 mm body, exposed pad xx xx

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