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LP-AM243: PRU CRC16/32 Module base code

Chen Gao
Prodigy 355 points
Part Number: LP-AM243

Hello,

     I am using PRU CRC16/32 module for communication data check with CRC16 (x16+x15+x2+1 ) mode.

I found that the accumulated CRC output results do not match to the CRC16 online tool.

For example, I pushed 0x1304 into CRC16 and get 0xc2b9 as the results, but the correct result should be 0xf30c.

Below is the programming code:

; CRC16 enable.

    ldi32  r20, 0x00001304  ;  original data

    ldi      r25.b0, 0               ;  config CRC type

    xout     1, &r25, 1

    mov      r29, r20             ;  load CRC data

    xout     1, &r29, 2           ;  push CRC data to CRC16 module

    nop

    xin      1, &r29, 4       ;  load the accumlulated CRC result into PRU

May I have your comments?

BR,

Chen

  • 0
    TI__Mastermind 35732 points

    I have started looking into the issue. Let me get back by friday.

  • 0 in reply to Nilabh Anand
    TI__Prodigy 355 points

    Hi Nilabh,

        Any news on it ?

  • 0 in reply to Chen Gao
    TI__Mastermind 35732 points

    Hi Chen,

    I tried to follow your code, it seems your observation is correct. Let me check internally with the expert on this.

  • 0 in reply to Nilabh Anand
    TI__Mastermind 35732 points

    Hi Chen,

    1. As per TRM, R25 should be written 4 bytes at a time

    There is some info missing in TRM please find below.  It will be updated in next revision.

    2. PRU ICSS is based on little endian architecture, so the input data should be given as 0413

    3. Also For CRC16 mode, SW can read CRC_DATA_32_BFLIP[31:16] to get the correct bit order.

    Please find the working code below.

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