STM32F407 and CRC

[Pilous Droip]

Posted on January 19, 2018 at 11:55

Hello friends.

I created CRC calculator, but I don't know, how to compare results.

My input data:

uint32_t data[16] = {

      0x1234, 0x456, 0x78, 0x09,

      0x10, 0x100, 0x1000, 0x01,

      0x54, 0x35, 0x98, 0x2432,

      0x2255, 0xAEFB, 0xAAAA, 0xFFFF

};

Function to calculation:

uint32_t CRC_Calculate32(uint32_t* arr, uint32_t count, uint8_t reset)

{

      /* Reset CRC data register if necessary */

      if (reset) {

            /* Reset generator */

            LL_CRC_ResetCRCCalculationUnit(CRC); 

      }

      /* Calculate CRC */

      while (count--) {

            /* Set new value */

            LL_CRC_FeedData32(CRC, *arr++); 

      }

      /* Return data */

      return LL_CRC_ReadData32(CRC); 

}

And I call this function:

uint32_t result;

Init_CRC();

result = CRC_Calculate32(data, 16, 1);

And result is: 0xb0829f24

#crc32 #stm32f4discovery

[Tesla DeLorean]

Posted on January 19, 2018 at 14:06

DF8A8A2B

DF8A8A2B

00001234 00000456 00000078 00000009 00000010 00000100 00001000 00000001

00000054 00000035 00000098 00002432 00002255 0000AEFB 0000AAAA 0000FFFF

B0829F24 test

// STM32 CRC32 Test App -

mailto:[e-mail]

#include <windows.h>

#include <stdio.h>

DWORD Crc32(DWORD Crc, DWORD Data)

{

int i;

Crc = Crc ^ Data;

for (i = 0; i < 32; i++)

if (Crc & 0x80000000)

Crc = (Crc << 1) ^ 0x04C11DB7; // Polynomial used in STM32

else

Crc = (Crc << 1);

return (Crc);

}

DWORD Crc32Fast(DWORD Crc, DWORD Data)

{

static const DWORD CrcTable[16] =

{ // Nibble lookup table for 0x04C11DB7 polynomial

0x00000000, 0x04C11DB7, 0x09823B6E, 0x0D4326D9, 0x130476DC, 0x17C56B6B,

0x1A864DB2, 0x1E475005, 0x2608EDB8, 0x22C9F00F, 0x2F8AD6D6, 0x2B4BCB61,

0x350C9B64, 0x31CD86D3, 0x3C8EA00A, 0x384FBDBD };

Crc = Crc ^ Data; // Apply all 32-bits

// Process 32-bits, 4 at a time, or 8 rounds

Crc = (Crc << 4) ^ CrcTable[Crc >> 28]; // Assumes 32-bit reg, masking index to 4-bits

Crc = (Crc << 4) ^ CrcTable[Crc >> 28]; // 0x04C11DB7 Polynomial used in STM32

Crc = (Crc << 4) ^ CrcTable[Crc >> 28];

Crc = (Crc << 4) ^ CrcTable[Crc >> 28];

Crc = (Crc << 4) ^ CrcTable[Crc >> 28];

Crc = (Crc << 4) ^ CrcTable[Crc >> 28];

Crc = (Crc << 4) ^ CrcTable[Crc >> 28];

Crc = (Crc << 4) ^ CrcTable[Crc >> 28];

return (Crc);

}

void test(void)

{

DWORD data[16] = {

0x1234, 0x456, 0x78, 0x09,

0x10, 0x100, 0x1000, 0x01,

0x54, 0x35, 0x98, 0x2432,

0x2255, 0xAEFB, 0xAAAA, 0xFFFF

};

DWORD Crc;

int i;

for (i = 0; i < 16; i++)

printf('%08X ', data[i]);

putchar('\n');

Crc = 0xFFFFFFFF; // Initial state

for (i = 0; i < 16; i++)

{

Crc = Crc32Fast(Crc, data[i]); // 4-bytes at a time

}

printf('%08X test\n', Crc);

}

int main(int argc, char **argv)

{

printf('%08X\n\n', Crc32(0xFFFFFFFF, 0x12345678)); // 0xDF8A8A2B

printf('%08X\n\n', Crc32Fast(0xFFFFFFFF, 0x12345678)); // 0xDF8A8A2B

test();

return (1);

}

[Pilous Droip]

Posted on January 19, 2018 at 14:26

Clive One, thank you.

It looks like very good.

[Tesla DeLorean]

Posted on January 19, 2018 at 14:54

When the forum starts working properly I'll try to edit the post with source code formatting, just can't make that happen in the current state.