CRC-16-IBM using HAL APIs

[newbie_stm32]

Hi community, I am working on CRC generation with polynomial 0x8005 and initial value 0x0000, so I configured it as below

I am using the data as shown below and the CRC should be 0x43B8 but the value got from the API is different. So I am missing something.

uint32_t bufer[] = { 0x23, 0x41, 0x54, 0x4F, 0x4E, 0xFF, 0x53, 0x4C, 0x30, 0x43, 0x55, 0x52, 0xFF, 0x0A, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39 };
uint32_t crc = HAL_CRC_Calculate(&hcrc, bufer, sizeof(bufer));

I appreciate your input.

[newbie_stm32]

Hi thanks for your inputs

[Tesla DeLorean]

link1 with hex 23 41 54 4F 4E FF 53 4C 30 43 55 52 FF 0A 30 31 32 33 34 35 36 37 38 39

also 0x43BD

Ok, so are we still looking for a STM32 HW example?

If the HW reports different values one or more of the settings is wrong. The implementation is difficult, and sensitive to bit and byte ordering. It's also not a reentrant resource.

[Tesla DeLorean · Accepted solution]

0xE2CB is a left shifting answer

#include <windows.h>
 
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
 
typedef unsigned char uint8_t;
typedef unsigned short uint16_t;
 
int main(int argc, char **argv)
{
  int i, j, k;
  uint16_t crc;
  uint8_t test[] = { 0x23,0x41,0x54,0x4F,0x4E,0xFF,0x53,0x4C,0x30,0x43,0x55,0x52,0xFF,0x0A,0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39 };
 
#define POLY 0x8005
 
  crc = 0x0000;
 
  for(j=0; j<sizeof(test); j++)
  {
    crc = crc ^ (test[j] << 8);
 
    for(i=0; i<8; i++)
    {
      if (crc & 0x8000)
        crc = (crc << 1) ^ POLY;
      else
        crc = (crc << 1);
    }
  }
 
  printf("crc=%04X\n", crc);
 
  return(1);
}

0x43BD is the right shifting answer with the 0xA001 poly (ie 0x8005 reversed)

#include <windows.h>
 
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
 
typedef unsigned char uint8_t;
typedef unsigned short uint16_t;
 
int main(int argc, char **argv)
{
  int i, j, k;
  uint16_t crc;
  uint8_t test[] = { 0x23,0x41,0x54,0x4F,0x4E,0xFF,0x53,0x4C,0x30,0x43,0x55,0x52,0xFF,0x0A,0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39 };
 
#define POLY 0xA001
 
  crc = 0x0000;
 
  for(j=0; j<sizeof(test); j++)
  {
    crc = crc ^ test[j];
 
    for(i=0; i<8; i++)
    {
      if (crc & 0x0001)
        crc = (crc >> 1) ^ POLY;
      else
        crc = (crc >> 1);
    }
  }
 
  printf("crc=%04X\n", crc); // 0x43BD
 
  return(1);
}

[Tesla DeLorean]

I've posted MODBUS examples for STM32 HW before, here's illustration we're talking about same algo

#include <windows.h>
 
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
 
typedef unsigned char uint8_t;
typedef unsigned short uint16_t;
 
uint16_t Crc16ModbusFast(uint16_t Crc, size_t Size, uint8_t *Buffer) // sourcer32@gmail.com
{
  static const uint16_t CrcTable[16] = { // Nibble lookup for 0xA001 polynomial
    0x0000,0xCC01,0xD801,0x1400,0xF001,0x3C00,0x2800,0xE401,
    0xA001,0x6C00,0x7800,0xB401,0x5000,0x9C01,0x8801,0x4400 };
  while(Size--)
  {
    Crc = Crc ^ *Buffer++;
    // Process 8-bits, 4 at a time, or 2 rounds
    Crc = (Crc >> 4) ^ CrcTable[Crc & 0xF];
    Crc = (Crc >> 4) ^ CrcTable[Crc & 0xF];
  }
  return(Crc);
}
 
int main(int argc, char **argv)
{
  int i, j, k;
  uint16_t crc;
  uint8_t test[] = { 0x23,0x41,0x54,0x4F,0x4E,0xFF,0x53,0x4C,0x30,0x43,0x55,0x52,0xFF,0x0A,0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39 };
 
#define POLY 0xA001
 
  crc = 0x0000;
 
  for(j=0; j<sizeof(test); j++)
  {
    crc = crc ^ test[j];
 
    for(i=0; i<8; i++)
    {
      if (crc & 0x0001)
        crc = (crc >> 1) ^ POLY;
      else
        crc = (crc >> 1);
    }
  }
 
  printf("crc=%04X\n", crc); // 0x43BD
 
  printf("crc=%04X\n", Crc16ModbusFast(0, sizeof(test), test)); // 0x43BD
 
  return(1);
}

[Tesla DeLorean]

Here's the SPL variant, you'll need to set the initialization value to zero, but this should give you all the boxes you need to check.

https://github.com/cturvey/RandomNinjaChef/blob/main/STM32F3_DISCO_Programmable_CRC_SPL_Example.c

[newbie_stm32]

@Community member​ thanks for the e.g

[newbie_stm32]

> Ok, so are we still looking for a STM32 HW example?

No, it's done I got it.