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evaluate: ds2775?s2778 ds2775?s2778 evaluation kits ________________________________________________________________ maxim integrated products 1 19-4673; rev 2; 10/09 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 ds2775?s2778 evaluation kits (ev kits) make per-formance evaluation, software development, and proto- typing with the ds2775?s2778 2-cell stand-alone fuel-gauge ics with li-ion (li+) protector and sha-1 authentication easy. the evaluation boards interface to a pc through a ds9123o usb adapter and rj11 cable connection. the provided cd-rom contains all related data sheets along with the evaluation software, which can be run under any windows xp or older operating system (os) that supports usb operation.the ds2775?s2778 ev kit software gives the user complete control of all the ds2775?s2778 functions. separate control tabs allow the user access to all eeprom and ram memory locations, control registers, real-time updates of all monitored parameters, and sha-1 functions. the software also incorporates a data- logging feature to monitor a cell over time. the evaluation board circuit is designed to provide the ds2775?s2778 with accurate parameter measure- ments. kit demonstration boards vary as they are improved upon over time. evaluation kit contents 1 pc. evaluation board1 pc. ds9123o usb adapter 1 pc. rj11 cable features ? demonstrate the capabilities of theds2775?s2778 including: estimation of available capacity for li+ cells2-cell voltage measurement current measurement current accumulation temperature measurement information storage identification overvoltage/undervoltage protection overcurrent/short-circuit protection secure challenge and response authentication using the sha-1 algorithm (ds2776 and ds2778 only) ? interface to the usb port of a pc running awindows xp or older os that supports usb operation ordering information equipment needed 1) a pc running a windows xp or older os with a cd- rom drive and an available usb port. 2) cables with minigrabber-style clips or the ability to solder directly to connection pads. 3) a li+ battery and a power supply and/or load circuit. part tpe ds2775evkit +e v k i t DS2776EVKIT +e v k i t ds2777evkit +e v k i t ds2778evkit +e v k i t windows xp is a registered trademark of microsoft corp. + denotes lead(pb)-free and rohs compliant. downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits 2 _______________________________________________________________________________________ setup and installation board connections note: in the following sections, software-related items are identified by bolding. text in bold refers to items directly from the ev kit software. text in bold and underlined refers to items from the windows operating system.connections to the tdfn demonstration board are best made either by soldering directly to the pads or by using cables with minigrabber clips. communication to the tdfn board can be accomplished either through the rj11 jack by connecting the provided standard six- conductor rj11 cord, by wiring directly to the dq and p- pads for the ds2775/ds2776, or by wiring directly to the sda, scl, and p- pads for the ds2777/ds2778. to use the demonstration software, the required communi- cation lines must be connected to the ds9123o com- munication brick using either of the two methods described. figures 2a and 2b show the recommended circuits to simulate charging and discharging. the li+ cell is con- nected between the b+ and b- pads. the battery charger/power supply or circuit load is connected between the p+ and p- pads. the evaluation software can be run in either configuration as long as two cells are connected between the b1+ and b1- terminals and b2+ and b2- terminals, providing a minimum of +2.5v to power the ds2775?s2778. software installation the ev kit software can be found on our website at www.maxim-ic.com/tools/evkit/ . to install the ds2775?s2778 ev kit software, exit all programs cur-rently running and unzip the downloaded file. double- click the setup.exe icon and the installation process begins. follow the prompts to complete the installation.the ds2775?s2778 ev kit software can be uninstalled with the add/remove programs tool in the control panel . after the installation is complete, open the ds2775?s2778 ev kit folder and run ds2775-8k.exe or select ev kits from the program menu. a splash screen containing information about the evaluation kitsappears as the program is being loaded. the software automatically detects if the ds2775/ds2776 are con- nected and selects 1-wire communication (as well as selects the appropriate 1-wire speed) or if theds2777/ds2778 are connected and selects 2-wire communication. rj11 sda p- dq b1+ scl pio p+ b1- b2+b2- figure 1. communication connections p+ b1+ b1- b2+ b2- + batterybattery -+ - p- ds2775k ds2776k ds2777k ds2778k ev board powersupply/ battery charger figure 2a. charging circuit p+ b1+ b1- b2+ b2- + batterybattery -+ - p- ds2775k ds2776k ds2777k ds2778k ev board load figure 2b. discharging circuit 1-wire is a registered trademark of maxim integrated products, inc. downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits _______________________________________________________________________________________ 3 selecting the communication port if the ds9123o is connected when the ds2775ds2778 ev kits start, the software starts up automati- cally. if it is not connected, the select preferences window opens (figure 3).in this window, select either serial port or usb and the port number , then click ok . the ds2775?s2778 ev kit software saves this port selection and automaticallyuses the selection each time the program starts. to change the port later, click the preferences option (figure 10) on the menu bar, select edit preferences , and then select the appropriate port. to attempt toautomatically locate the ds9123o or ds9123, click the poll ports button. warning: automatically polling for the ds9123 can disrupt other devices connected toyour computer? com ports. program menus several pulldown menu options are provided to simplifyusing the ds2775?s2778 ev kit software. their func- tions are individually detailed in the following sections. the file menu (figure 4) allows the user to store and recall information to and from a file directly into the textboxes on the parameters tab (figure 24). these func- tions do not directly write or read the ds2775?s2778.it is still necessary for the user to store or recall this information to or from the device by clicking on the write & copy or recall & read buttons on the parameters tab (figure 24). the registers menu (figure 5) gives immediate access to all seven status and function registers of theds2775?s2778. selecting any of the registers opens an individual control window, giving the user a descrip- tion of each register bit and the ability to read or write it. see figure 6. figure 3. select preferences window figure 4. file menu figure 5. registers menu downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits 4 _______________________________________________________________________________________ the present state of all register bits is displayed imme-diately upon opening the register window. r/w loca- tions contain a selection field or command button to allow the user to determine their state. pressing the write button writes the new value to the register and reads the corresponding register inside theds2775?s2778 to verify the correct value was written. the control register and protection threshold register are stored in eeprom, so when the write command is issued, the value is written and copied to eepromwithout changing the values of the remainder of the parameter eeprom block. the communication menu (figure 7) allows the user to detect the appropriate communication protocol forthe device in use. the ds2775?s2778 ev kits auto- matically detect which device type is connected and display the appropriate information. figure 7. communication menu figure 6. status register downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits _______________________________________________________________________________________ 5 figure 8. tools menu figure 9. sha-1 calculator if the ds2775/ds2776 are found by the software, the1-wire speed of the device is detected and displayed. to change the speed of the device, simply left-click on set overdrive or clear overdrive from the communication menu (figure 7). selecting either option sends the clear overdrive or set overdrivecommand. the software sends the command in the current 1-wire speed, and then begins communicating in the new 1-wire speed. if the d2777/ds2778 are found by the software, the 2-wire slave address is detected and displayed under the communication menu. if the software and the ds2775?s2778 get out of sync, simply left-click ondetect device to match the software? communication to the device.the tools menu (figure 8) provides two methods to evaluate the sha-1 calculations: a method to view thesoftware-computed mac and a method to view the sha-1 calculator. left-clicking on the show software computed mac menu item expands the main window to show the mac computed by the software.left-clicking on the show sha-1 calculator menu item opens a new window that allows the user to per-form sha-1 calculations independent of the ds2775 ds2778 (figure 9). simply fill in the text boxes with the desired values and left-click on the compute mac with software button. if the rom id is to be used in computing the mac, check the use rom id? check- box. use the fill with values from main form option from the options menu to fill the secret , rom id , and challenge text boxes with values from the main pro- gram window.the preferences menu allows the user to change com port settings at any time (figure 10). edit preferences opens the select preferences window. see the selecting the communication port section for more information. downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits 6 _______________________________________________________________________________________ selecting the about topic from the help menu (figure 11) opens a window containing information about thecurrent revision of this program and maxim integrated products, inc. program tabs all program functions are divided under four tabs in themain program window. left-click on the appropriate tab to move to the desired function page. located on the real time tab (figure 12) is all the information mea- sured and calculated by the ds2775?s2778. thatdata is divided between the parametric data , fuel gauge data , and sha-1 subtabs. the parameters tab (figure 24) gives the user access to the entire parame-ter eeprom memory block in terms of application units and device units. the memory tab (figure 26) displays the contents of every register and memory locationinside the ds2775?s2778 and allows the user to alter the data. the log data tab (figure 27) allows the user to store all real-time information to a file and view thedata in a graphical form. real time tab the real time data tab is divided into three subtabs: parametric data , fuel gauge data , and sha-1 . the parametric data subtab (figure 12) contains all the real-time measurements taken by the ds2775?s2778.the fuel gauge data subtab contains all the fuel- gauge values calculated by the ds2775?s2778. thesha-1 subtab allows the user to exercise the sha-1 encryption algorithm. the sha-1 functions are onlysupported by the ds2776 and ds2778. the parametric data subtab displays the latest real- time measurements of cell voltages, temperature, cur-rent, and accumulated charge with both analog meter readouts and digital values. the sense-resistor value used to calculate the current reading is shown in the temperature section. go to the sense resistor (mohms) value on the parameters tab (figure 24) to change this value.the present states of the charge control and discharge control pins are shown at the bottom of the window. these outputs are active low and drive two control fets, allowing charging and discharging of the cell pack. the charge control pin can be controlled manually by left- clicking the disable charging and enable charging buttons and is forced high automatically by either anovervoltage or charge overcurrent condition. the dis- charge control pin can also be controlled manually with the disable discharging and enable discharging but- tons and is forced high automatically by either an under-voltage or discharge overcurrent condition. the present state of each of the four possible flag con- ditions (overvoltage, undervoltage, charge overcurrent, and discharge overcurrent) are represented by leds inside the voltage and current sections of the window. the corresponding led is green while the flag is in the cleared state. if conditions cause a flag to be tripped, the led turns red and a button appears that allows the user to clear the flag, provided that clear conditions have been met. if conditions for clearing the flag have not been met by the circuit, clicking the clear button has no effect. figure 10. preferences menu figure 11. help menu downloaded from: http:///
the present state of the pio pin is shown in text. theset/clear pio bit button sets or clears the pio bit in the special feature register to toggle the pin? state.the user can bring up the set accumulated current register window (figure 13) by left-clicking the set acr button. this window allows the user to enter a value for the accumulated current register in mahrs. evaluate: ds2775?s2778 ds2775?s2778 evaluation kits _______________________________________________________________________________________ 7 figure 12. parametric data subtab figure 13. set accumulated current register downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits 8 _______________________________________________________________________________________ the user can bring up the set accumulation bias register window (figure 14) by left-clicking the acc bias button. this window allows the user to enter val- ues for the accumulation bias register in ma. left-click-ing on the write button writes the accumulation bias register and copies the value to eeprom. the valueentered here is added to the accumulated current reg- ister during each current conversion. the bias value does not affect the current register reading but is reflected in the accumulated current register. the user can bring up the set current offset bias register window (figure 15) by left-clicking the current offset bias button. this window allows the user to enter values for the current offset bias registerin ma. left-clicking on the write button writes the current offset bias register and copies the value toeeprom. the value entered here is added to the current register during each current conversion. the user can start an automatic current offset calibration by left-clicking on the calibrate button. the fuel gauge data subtab displays the latest fuel- gauge calculations (figure 16). the full , active empty , and stand-by empty levels are calculated from the data input on the parameters tab (figure 24). the remaining active absolute capacity ( raac ) and the remaining stand-by absolute capacity ( rsac ) are displayed in terms of mahr. the remaining active rela-tive capacity ( rarc ) and remaining stand-by relative capacity ( rsrc ) are displayed in terms of percent of capacity remaining. the analog meter on the left dis-plays the remaining active absolute capacity ( raac ). the flags found in the status register are displayed onthe right side of the window. when the under voltage flag or the power-on-reset flag is set, a button appears that allows the user to clear those bits. theuser can also issue a software power-on reset com- mand by left-clicking the soft por button. figure 14. set accumulation bias register figure 15. set current offset bias register downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits _______________________________________________________________________________________ 9 figure 16. fuel gauge data tab the user can bring up the set age scalar window (figure 17) by left-clicking the update button in the scalar area of the fuel gauge data subtab. this win- dow allows the user to read and write the scalar valuein terms of percent of the nominal capacity. figure 17. scalar register downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits 10 ______________________________________________________________________________________ the ds2776/ds2778 use an 8-byte secret , the 8-byte rom id code of the device, and an 8-byte challenge to generate a 20-byte message digest (also called themac ) using the sha-1 encryption algorithm. see figure 18. the ds2775/ds2777 do not support thesha-1 functions. the user can clear the 8 bytes of the secret by left- clicking on the clear secret button. the top-right text box is the lsb of the secret, and the bottom-left text box is the msb of the secret. (all text boxes are dis- played in this same format.) see figure 19.the user can also permanently lock the secret by left- clicking on the lock secret button. once the secret is locked, it cannot be changed and cannot be read fromthe ds2776/ds2778. the software prompts the user to make sure the secret is ready to be permanently locked. figure 19. the secret figure 20. the rom id figure 18. sha-1 tab downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits ______________________________________________________________________________________ 11 another ds2776/ds2778 feature is to generate the nextsecret from the existing secret, rom id, and challenge. it is important to click write challenge before left-click- ing the compute next secret or compute next secret with id button. the device performs the sha-1 calculation and creates the next secret. the softwareperforms sha-1 calculation based on the values in the text boxes for the secret, rom id (if desired), and chal- lenge and places the new secret, as calculated by soft- ware, in the secret text boxes. the new secret is never read back from the device.it is important for the software and the ds2776/ds2778 to have identical secrets, rom ids, and challenges so the software can properly verify the operation of the ds2776/ds2778. if the software is not in sync with the device, simply clear the secret to get the software and hardware back in sync. the ds2776/ds2778 have two commands to compute the next secret. the compute next secret with id command uses the secret, the rom id, and the chal-lenge to perform the sha-1 encryption algorithm. the compute next secret command uses the secret and the challenge, but replaces the rom id with 0xffs toperform the algorithm. the user can select which com- mand is used by left-clicking on the appropriate button. the rom id code is unique for each ds2776/ds2778device and cannot be changed by the user. the user can load the device? rom id into the rom id text boxes by left-clicking on the read rom ?33h or read rom ?39h buttons, depending on the setting of the rnaop bit of the control register for the ds2776 or byleft-clicking on the read rom id button for the ds2778. see figure 20.if multiple 1-wire devices are on the bus, the user can use the search rom function from the net address subtab of the memory tab (figure 26). left-click the find devices button and then left-click on the rom id that is desired to be used in the sha-1 algorithm. thevalue of the rom id appears in the rom id text boxes on the sha-1 subtab of the real time tab (figure 12). the challenge is a random 8-byte block that is used bythe ds2776/ds2778 to perform the sha-1 encryption algorithm (figure 21). each time the sha-1 is per- formed, either during a compute next secret (see figure 18) or a compute mac (see figure 22), the challenge is left in an undefined state. therefore, theuser must left-click on the write challenge button prior to each computation to get a proper sha-1 calculation.the user can left-click on the randomize challenge button to load a random challenge into the challenge text boxes. left-clicking this button does not write thechallenge to the device. it is still required that the user left-click on the write challenge button to write the challenge to the device.the mac is the 20-byte message digest that is the result of the sha-1 encryption algorithm (figure 22). when the secret has been loaded properly, the rom id has been read, and the challenge has been written to the device, left-clicking on the compute mac or compute mac with id button performs the sha-1 cal- culation, reads back the results, and then displaysthem in the mac text boxes. the software also performs the sha-1 calculationsbased on the secret , rom id (if desired), and challenge text box values and compares its results to the results read back from the ds2776/ds2778. if themac computed by the software and mac read back from the ds2776/ds2778 match, the software displays ?erified.?if they do not match, ?ot verified?is dis- played. the user can view the software-computed mac by selecting show software computed mac from the tools menu (figure 8). the user also can compute the mac with the ds2776/ds2778, then change one bit inone of the text boxes of the secret, and then compute the mac with software to see how big of a difference changing one bit makes. see figure 23. figure 21. the challenge figure 22. the mac figure 23. software computed mac downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits 12 ______________________________________________________________________________________ if the mac is ?ot verified,?make sure that the chal-lenge was written prior to computing the mac. if the ?ot verified?error continues, perhaps the secret in the device does not match what is in the secret text boxes and the user needs to clear the secret of the ds2776/ds2778. parameters tab the parameters tab gives the user access to the entire parameter eeprom memory block (block 1, addresses60h?fh) in terms of application units and device units. the application units subtab displays the parameters in units like ma, mahrs, and v (figure 24). the device units (read only) subtab performs the calculations needed to get the application units into the units thatare stored in the device like ?, ?hrs, and ppm as well as show the hexadecimal values that are written to thedevice. the application units subtab allows the user to read and write the parameter eeprom memory block. tochange any of this information, simply click on the desired text field and enter the new value. clicking on the load default set up button enters example data into the information fields of theapplication units subtab. once all data is in the desired format, click on the write & copy button to copy it to the ds2775?s2778? eeprom.this information can also be stored to a file and recalled later using the load set up or save set up buttons or the load parameter set up or save parameter set up option from the file menu (figure 4). figure 24. application units tab downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits ______________________________________________________________________________________ 13 these functions do not directly write or read theds2775?s2778. it is still necessary for the user to store or recall this information to or from the device by clicking the write & copy or recall & read buttons. the device units (read only) subtab is read only. it displays the actual hexadecimal values read from theds2775?s2778 and displays the units that are stored in the device. see figure 25. the memory tab (figure 26) gives the user access to all 32 bytes of sram and all 48 bytes of eeprominside the ds2775?s2778. they are separated into five subtabs for convenience. any value can be modi- fied by clicking in that address?text box and typing a new value in hexadecimal format. the write button copies the entire block of data to the correspondinglocation inside the ds2775?s2778 (scratchpad ram on the eeprom blocks). the read button updates the entire block? text boxes with data from theds2775?s2778 (scratchpad ram on the eeprom blocks). subtabs displaying any eeprom data also have copy and recall buttons to allow the user to transfer the data between scratchpad and eeprommemory internal to the ds2775?s2778. the permanently lock block 0 and permanently lock block 1 buttons permanently store the data currently located in that block? eeprom. warning: this data can never be changed once locked. verify your datafirst by issuing a recall and a read. figure 25. device units tab downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits 14 ______________________________________________________________________________________ the net address subtab allows the user to perform a search net address command to find all the 1-wiredevices on the 1-wire bus. all devices found on the bus are listed in the addresses fields. to communicate to any device on the bus, click on its address inside thenet addresses field to select it. the program now uses this net address for all operations until a different netaddress is chosen. if a ds2776/ds2778 is detected, then a separate button is displayed to allow the user to read the rom id of the 2-wire device. the log data tab allows the user to see the ds2775?s2778? real-time measurements graphedover time (figure 27). there are separate subtabs for voltage , current , temperature , and accumulated charge . each graph displays the last 500 data points collected by the ds2775?s2778 ev kit software. thesampling interval can be adjusted from as fast as pos- sible to 15min and can be adjusted from the sampling interval menu at the bottom of the window. the clear graphs button clears all data from all four graphs but does not reset the log to file function. the graphs arenot updated when the fastest sampling interval is selected, only the data logging is enabled. figure 26. memory tab downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits ______________________________________________________________________________________ 15 figure 27. log data tab the log to file subtab contains control information for storing all data to an ascii file. the default file name isc:\ds277xk_datalog.txt, but can be modified in the filename text field. the stop logging button toggles data logging off and on. data is stored at the sameinterval selected for updating the graphs in the tab- delimited format of: ?ime voltage1 voltage2 current avecurrent temperature acr full ae se raac rarc rsac rsrc status protection scalar?for easy import into a spreadsheet. the most recent 50samples are displayed in the window for observation. warning: the log data function overwrites previous file information. data previously stored in the file will be lost. downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits 16 ______________________________________________________________________________________ 10 pls 11 sda/dq 12 scl/ovd 9 pio 6 vb 2 v dd 4 v in2 5 v in1 14 cp 8 sns 7 v ss 1 cc 13 src 3 dc c1 1000pf c2 1000pf r8 150 r13 0.025 r9 150 r10 150 r11 150 r2 1k r1 (not populated) r3 1k r4 470 r51k r6150 r71k c3 0.1 f close to chip c4 0.1 f d4 schottky d3 5.6v zenner d2 5.6v zenner d1 5.6v zenner pk- pio scl dq sda pk+ bat1+bat1- bat2+ bat2- u2 fdw2501n ds2775 u1 c5 0.47 f c60.1 f r12 1k figure 28. ds2775?s2778 ev kit schematic downloaded from: http:///
evaluate: ds2775?s2778 ds2775?s2778 evaluation kits revision history revision number revision date description pages changed 0 1/09 initial release. 1 7/09 ? added ds2775-ds2778 ev ki schemaic . ? added link to ev kit software. 2, 15 2 10/09 changed the ordering informaion table to reflect pb-free part numbers. 1 maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit 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 ____________________ 17 2009 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. downloaded from: http:///

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