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UCD3138: UCD3138 CRC Response

ilgin sarican
Prodigy 215 points
Part Number: UCD3138

Hi,

For UCD3138 what poly and initial CRC value are used for CRC calculation?

  • 0
    TI__Intellectual 1790 points

    Hello,

    What does the CRC calculation use for?

    For UCD3138, we just have the CRC calculation for PEC in PMBus.

    Best Regards,

    Xuemei

  • 0 in reply to Xuemei Lu
    Prodigy 215 points

    Hi and thank you for your kind reply

    My problem is  I am reading UCD3138 with an USB to I2C converter I have build myself via I2C bus and

    getting the Vin Vout etc correctly.

    Now I want to program the limits etc on the chip and for that I need to calculate CRC8.

    Using CRC8 online calculators https://crccalc.com/ I find the CRC8 for say 0XDAD1 which is the value displayed on

    Texas Fusion Design On line program for a value of  22.53A to be  0x01 for poly = 07 and crc initial =0  

    the program displays different crc for different combination of poly and initial crc a total of 10 including

    that of MAXIM and ROHC etc and than with a TI USB interface Adaptor connected to UCD3831

    I am monitoring the I2C bus  with an oscilloscope and I see that the CRC8 byte send by the Fusion Design On line program

    is 0XBC which does not match to any of the results I get from online crc calculator

     and I have also written a program on visual studio to calculate the CRC myself and my results match that of the on line

    Crc calculation program . So I would kindly like to know how TI calculates CRC. If a table is used for CRC calculation could I receive it

     

    Kind Regards

  • 0 in reply to ilgin sarican
    TI__Intellectual 1790 points

    Hello,

    You could take a look at our PFC demo code, in which a PEC calculation algorithm is described. This is what UCD3138 used. It shall be in pmbus_common.c as shown below.

    PFC demo code: https://www.ti.com/tool/UCD3138FW-PFC?keyMatch=UCD3138%20PFC

    Best Regards,

    Xuemei