Calculate CRC-8

[parisa]

Hello,

I need to know how to calculate CRC-8 of input data.

I have a binary stream like (12586966 Dec or 0XC00FD6) and CRC-8(22 DEC, 0x16). Based on 0x97 polynomial how I can calculate my input binary stream CRC-8?

Thanks

[waclawek.jan]

Which STM32?

Give us also an example stream with the resulting correct CRC.

JW

[parisa]

Thank you for your swift comment.

My MCU is STM32F103. Here is data:

Transmitter:

Binary stream: ‭110000000000111111010110‬ (0XC00FD6)

CRC-8:‭ 00010110‬

And based on the datasheet the CRC-8 is obtained by initial polynomial 0x97 value.

[waclawek.jan]

The 'F103's CRC module allows to calculate only fixed-poly CRC-32, so you have to perform the calculation in software.

You will find numerous examples for CRC-8 in C on the internet.

JW

[Tesla DeLorean]

// 8-bit CRC Model - [e-mail]
// Copyright (C) 1988-2020, All Rights Reserved
 
#include <windows.h>
 
#include <stdio.h>
#include <stdlib.h>
 
#define POLY 0x97 // # 0x197 = x^8 + x^7 + x^4 + x^2 + x^1 +1 (0x97 -> 0x197)
 
unsigned char Slow_CRC_Cal8Bits(unsigned char crc, int Size, unsigned char *Buffer)
{
 int i;
 
 while(Size--)
 {
 crc = crc ^ *Buffer++; // Apply Byte
 
 for(i=0; i<8; i++) // Eight rounds of 1-bit
 {
 if (crc & 0x80)
 crc = (crc << 1) ^ POLY;
 else
 crc = (crc << 1); // Left Shifting
 }
 }
 
 return(crc);
}
 
unsigned char Quick_CRC_Cal8Bits(unsigned char crc, int Size, unsigned char *Buffer)
{
 static const unsigned char CrcTable[] = {
 0x00,0x97,0xB9,0x2E,0xE5,0x72,0x5C,0xCB, // 0x97 Polynomial Table, 4-bit, [e-mail]
 0x5D,0xCA,0xE4,0x73,0xB8,0x2F,0x01,0x96 };
 
 
 while(Size--)
 {
 crc = crc ^ *Buffer++; // Apply Byte
 
 crc = (crc << 4) ^ CrcTable[(crc >> 4) & 0xF]; // Two rounds of 4-bits
 crc = (crc << 4) ^ CrcTable[(crc >> 4) & 0xF];
 }
 
 return(crc);
}
 
unsigned char Fast_CRC_Cal8Bits(unsigned char crc, int Size, unsigned char *Buffer)
{
 static const unsigned char CrcTable[] = { // 0x97 Polynomial Table, 8-bit, [e-mail]
 0x00,0x97,0xB9,0x2E,0xE5,0x72,0x5C,0xCB,
 0x5D,0xCA,0xE4,0x73,0xB8,0x2F,0x01,0x96,
 0xBA,0x2D,0x03,0x94,0x5F,0xC8,0xE6,0x71,
 0xE7,0x70,0x5E,0xC9,0x02,0x95,0xBB,0x2C,
 0xE3,0x74,0x5A,0xCD,0x06,0x91,0xBF,0x28,
 0xBE,0x29,0x07,0x90,0x5B,0xCC,0xE2,0x75,
 0x59,0xCE,0xE0,0x77,0xBC,0x2B,0x05,0x92,
 0x04,0x93,0xBD,0x2A,0xE1,0x76,0x58,0xCF,
 0x51,0xC6,0xE8,0x7F,0xB4,0x23,0x0D,0x9A,
 0x0C,0x9B,0xB5,0x22,0xE9,0x7E,0x50,0xC7,
 0xEB,0x7C,0x52,0xC5,0x0E,0x99,0xB7,0x20,
 0xB6,0x21,0x0F,0x98,0x53,0xC4,0xEA,0x7D,
 0xB2,0x25,0x0B,0x9C,0x57,0xC0,0xEE,0x79,
 0xEF,0x78,0x56,0xC1,0x0A,0x9D,0xB3,0x24,
 0x08,0x9F,0xB1,0x26,0xED,0x7A,0x54,0xC3,
 0x55,0xC2,0xEC,0x7B,0xB0,0x27,0x09,0x9E,
 0xA2,0x35,0x1B,0x8C,0x47,0xD0,0xFE,0x69,
 0xFF,0x68,0x46,0xD1,0x1A,0x8D,0xA3,0x34,
 0x18,0x8F,0xA1,0x36,0xFD,0x6A,0x44,0xD3,
 0x45,0xD2,0xFC,0x6B,0xA0,0x37,0x19,0x8E,
 0x41,0xD6,0xF8,0x6F,0xA4,0x33,0x1D,0x8A,
 0x1C,0x8B,0xA5,0x32,0xF9,0x6E,0x40,0xD7,
 0xFB,0x6C,0x42,0xD5,0x1E,0x89,0xA7,0x30,
 0xA6,0x31,0x1F,0x88,0x43,0xD4,0xFA,0x6D,
 0xF3,0x64,0x4A,0xDD,0x16,0x81,0xAF,0x38,
 0xAE,0x39,0x17,0x80,0x4B,0xDC,0xF2,0x65,
 0x49,0xDE,0xF0,0x67,0xAC,0x3B,0x15,0x82,
 0x14,0x83,0xAD,0x3A,0xF1,0x66,0x48,0xDF,
 0x10,0x87,0xA9,0x3E,0xF5,0x62,0x4C,0xDB,
 0x4D,0xDA,0xF4,0x63,0xA8,0x3F,0x11,0x86,
 0xAA,0x3D,0x13,0x84,0x4F,0xD8,0xF6,0x61,
 0xF7,0x60,0x4E,0xD9,0x12,0x85,0xAB,0x3C };
 
 while(Size--)
 {
 crc = crc ^ *Buffer++; // Apply Byte
 
 crc = CrcTable[crc & 0xFF]; // One round of 8-bits
 }
 
 return(crc);
}
 
int main(int argc, char **argv)
{
 unsigned char crc;
 unsigned char test[] = { 0xC0, 0x0F, 0xD6 };
 
 /* The expected CRC value of test[] using the polynomial 0x97 is 0x16, when initialized with 0x00 */
 
 printf("crc=%02X Slow\n", Slow_CRC_Cal8Bits(0x00, sizeof(test), test));
 
 printf("crc=%02X Quick\n", Quick_CRC_Cal8Bits(0x00, sizeof(test), test));
 
 printf("crc=%02X Fast\n", Fast_CRC_Cal8Bits(0x00, sizeof(test), test));
 
 return(1);
}

[waclawek.jan]

... or just wait until Clive brings it to you on a silver plate... ;)

JW

[parisa]

Hello all,

I am sorry for delay in my response. I really appreciate your help and your code with has been set for my CRC algorithm.

Thank you again for everything.