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BQ79606A-EXAMPLE-CODE: ReadReg() function issue

Eric_L
Intellectual 345 points
Part Number: BQ79606A-EXAMPLE-CODE
Other Parts Discussed in Thread: BQ79606A-Q1

Hi support,

I am able to read the cells voltage back and enable the cell balance, all FETs are in their expected states. But I can not read the status back (always 0) with following code:

BYTE bFrame = 0;
ReadReg(0, CB_SW_STAT, &bFrame, 1, 0, FRMWRT_SGL_R);
int pStat = (int)(bFrame & 0x3F);
printf("Passive switch status: %d\n", pStat);

/* or
ReadReg(0, DEV_STAT, &bFrame, 1, 0, FRMWRT_SGL_R);
int pStat = (int)((bFrame >> 4) & 0x1);
printf("Passive CB status: %d\n", pStat);
*/

In BQ79606A-Q1 Software Design Reference under 4.7 section, it mentions:

80 00 02 00 00 84 1E // read PARTID
80 00 02 04 00 86 DE // read DEV_STAT
80 00 02 06 00 87 BE // read FAULT_SUM
• 80 = Single device read of 1 byte
• 00 = Device 0
• 0200, 0204, 0206 = Register address 0x200, 0x204, 0x206
• 00 = Read back one byte of data
• 841E, 86DE, 87BE = CRC

So does my ReadReg() function sending the right code of: 80 00 02 04 00 86 DE ?

Please advise.

Thanks,

Eric

  • 0
    TI__Genius 17370 points

    Hi Eric,

    All the other commands for PARTID and FAULT_SUM work correctly as well? Did you complete balancing or any other functions that would make DEV_STAT change from 0x00? If you read the register summary in the datasheet, ensure one of the bits would go high as expected otherwise it could be correct.

    Regards,

    Taylor

  • 0 in reply to Taylor Vogt
    Intellectual 345 points

    Hi Taylor,

    None of those status can be read back correctly (always 0)!

    Can you explain how to implement the function

    #_of_Read_Bytes = ReadReg(Device_Address, Register_Address, Incoming_Data_Byte_Array,
    #_Data_Bytes, ms_Before_Time_Out, Packet_Type)

    to send the code of 80 00 02 04 00 86 DE ?

    Thanks,

    Eric

  • 0 in reply to Taylor Vogt
    Intellectual 345 points

    Hi Taylor,

    Okay, some kind of figure it out. But can you explain why the  read back data byte is staying in response_frame2[4] in void AutoAddress() function within bq79606.c? And how to implement it with only passing a single byte type parameter and read it back?

    // //OPTIONAL: read back all device addresses
    // WriteReg(0, COMM_TO, 0x00, 1, FRMWRT_ALL_NR); //Disable communication timeout because printf takes a long time
    // for (nCurrentBoard = 0; nCurrentBoard < TOTALBOARDS; nCurrentBoard++) {
    // memset(response_frame2, 0, sizeof(response_frame2));
    // ReadReg(nCurrentBoard, DEVADD_USR, response_frame2, 1, 0, FRMWRT_SGL_R);
    // printf("Board %d=%02x\n",nCurrentBoard,response_frame2[4]);

    Thanks,

    Eric

  • 0 in reply to Eric_L
    TI__Genius 17370 points

    Hi Eric,

    I am not sure I understand the question, can you please explain what the intention would be to do? It is better to not edit any structure in bq79606.c and only edit the code you want to execute within sysmain.c file only. (and bq79606.h just to edit totalboards variable in case the # of stack devices changes).

    Regards,

    Taylor

  • 0 in reply to Taylor Vogt
    Intellectual 345 points

    Hi Tylor,

    That is the way I used to read the data back from the register in my main file, and I don't intent to modify any codes in bq79606.c but will need some help to understand it. Hopefully I can see some real codes or explanation instead of  just a simple reference link.

    Thanks,

    Eric

  • 0 in reply to Eric_L
    TI__Genius 17370 points

    Hi Eric,

    I apologize but I'm still not sure exactly what you are looking for, perhaps this thread explanation below may help with background. Most everything in bq79606.c is just the layer to put in correct UART structure as per datasheet section "Command and Response Protocol Layer" or functions used in sys main. I think that portion of code was just designed to read back the device address to confirm autoaddressing was done correctly (please read up on this in the datasheet). And the function ReadReg is explained in section 1.2 of the user guide for how to change it to support other commands, there is an example nRead = command which you are free to change out register name, byte length etc. and should be self-explanatory to change for what you want using this example.

    https://e2e.ti.com/support/power-management/f/196/t/868854?tisearch=e2e-sitesearch&keymatch=bq79606a%25252520example%25252520code%25252520readreg

    Regards,

    Taylor

  • 0 in reply to Taylor Vogt
    Intellectual 345 points

    Hi Taylor,

    Specifically, I want to know why the read back data is in the [4] of the array when only 1 byte of data is required.

    // ReadReg(nCurrentBoard, DEVADD_USR, response_frame2, 1, 0, FRMWRT_SGL_R);
    // printf("Board %d=%02x\n",nCurrentBoard,response_frame2[4]);

    And what is wrong by doing the following?

    BYTE bFrame = 0;
    ReadReg(0, DEV_STAT, &bFrame, 1, 0, FRMWRT_SGL_R);

    Thanks,

    Eric

  • 0 in reply to Eric_L
    TI__Genius 17370 points

    Eric,

    As I said above I think that portion of code was just designed to read back the device address to confirm autoaddressing was done correctly (please read up on this in the datasheet), so it would be several device addresses to print out for each board. Again, follow the exact structure of our example to edit commands for the second part, you are missing nRead and the full structure. 

    Regards,

    Taylor