TMS570LS1224: CRC data computation

Sakthi Sundaram

Part Number: TMS570LS1224

I am using TMS570LS1224 DSP for establishing SPI communication with the slave device. I tried computing the CRC data bit for the data bits but the computed result is not matching with example given in the attached picture.

Is there any online crc calculator to do this computation? How to implement CRC with TMS570 device?

over 3 years ago

0 QJ Wang over 3 years ago

TI__Guru**** 198766 points

Hi Sakthi,

The SPI module supports parity feature, but doesn't support CRC calculation. TMS570LS1224 device has a built-in CRC module for calculating CRC based on 64-bit polynomial: f(x)=x^64 + x^4 + x^3 + x + 1

If you want to transmit CRC with data through SPI, the CRC polynomial on both master and slave sides should be the same.

You can write SW to calculate the CRC on TMS570LS12x, but we don't have example code for this specific polynomial.

0 Sakthi Sundaram over 3 years ago in reply to QJ Wang

Intellectual 280 points

I understand that example code is not there for generating the CRC for this particular polynomial. I want to know if there are CRC calculator to verify the CRC byte (0xAA) given for start config command 0X3A. So, that i can calculate CRC byte for other commands and directly invoke into the code instead of using CRC polynomial generator.

0 QJ Wang over 3 years ago in reply to Sakthi Sundaram

TI__Guru**** 198766 points

Hi Sakthi,
Please take a look at tis example code for CRC8-CITT:
uint8_t  _crc8_ccitt_update (uint8_t inCrc, uint8_t inData)
{
    uint8_t i;
    uint8_t data;
    data = inCrc ^ inData;
    for ( i = 0; i < 8; i++ )
    {
          if (( data & 0x80 ) != 0 )
         {
              data <<= 1;
              data ^= 0x07;
         }
        else
        {
              data <<= 1;
        }
   }
   return data;
}
The code is from: https://www.nongnu.org/avr-libc/user-manual/group__util__crc.html
Another example:
https://www.ti.com/lit/an/sbaa456/sbaa456.pdf?ts=1654660477218&ref_url=https%253A%252F%252Fwww.google.com%252F

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TMS570LS1224: CRC data computation