CRC for polynomial 0xedb88320

suhas_prabhu — Mon, 22 Jul 2019 10:51:50 GMT

Hello,

I am facing the issue with CRC32 calculation using hardware CRC functions. I tried with the "0xedb88320" for MK22FN512VLL12. I am not able to get the CRC value right.

Is there any sample code (with hardware configuration values set and working) that can provide a comparison to calculate CRC32 using hardware and software ?

I hope i can use the CRC hardware function from K22.

I have a reference table from

link : //https://publications.qld.gov.au/dataset/8ffa941e-6efc-43fb-a207-202018baf3d2/resource/8c62a217-35db-419f-b625-7db213382ab7/download/hashingalgorithms-v1-6.pdf

unsigned long int CRC32Table[] = { /* CRC polynomial 0xedb88320 */
0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535,
0x9e6495a3,
0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, ..................

};

Hope to get some help on that.

Regards,

Suhas

Re: CRC for polynomial 0xedb88320

Robin_Shen — Tue, 23 Jul 2019 03:12:56 GMT

Hi Suhas,
Please refer the description of CRC32 Demystified:

There is crc example in MCUXpresso SDK_2.6.0_MK22FN512xxx12(...SDK_2.6.0_MK22FN512xxx12\boards\frdmk22f\driver_examples\crc)

In that example, we will get checksum32 == checkCrc32(0xcbf43926u).

Please have a try on that example.

Best Regards,

Robin

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Re: CRC for polynomial 0xedb88320

mjbcswitzerland — Tue, 23 Jul 2019 08:26:58 GMT

Here is the CRC32 test code from the uTasker project, including errate 2776 workaround (not be needed for K22), which checks the CRC32 of an Ethernet frame (with CRC32 at end of the input data)

        if (rx_frame->frame_size != 0) {
            unsigned long ulLength = rx_frame->frame_size;
            unsigned long *ptr = (unsigned long *)rx_frame->ptEth;
            POWER_UP_ATOMIC(6, CRC);                                     // power up the CRC module
            CRC_CTRL = (CRC_CTRL_TCRC_32 | CRC_CTRL_TOTR_BITS_BYTES | CRC_CTRL_TOT_BITS_BYTES | CRC_CTRL_FXOR); // mode required for CRC-32 IEEE compatibility
            CRC_GPOLY = 0x04c11db7;                                      // set the polynomial
            CRC_CTRL = (CRC_CTRL_TCRC_32 | CRC_CTRL_WAS | CRC_CTRL_TOTR_BITS_BYTES | CRC_CTRL_TOT_BITS_BYTES | CRC_CTRL_FXOR); // enable write of seed
            CRC_CRC = 0xffffffff;                                        // seed is 0xffffffff
            CRC_CTRL = (CRC_CTRL_TCRC_32 | CRC_CTRL_TOTR_BITS_BYTES | CRC_CTRL_TOT_BITS_BYTES | CRC_CTRL_FXOR); // switch back to data input mode
            while (ulLength >= 4) {                                      // main part using long words
                CRC_CRC = *ptr++;                                        // process long world
                ulLength -= 4;                                           // by bytes at a time - the CRC calculation requires 2 clock cycles
            }
        #if !defined ERRATA_ID_2776
            if (ulLength != 0) {                                         // remaining bytes that didn't fit into a long word
                unsigned char *ptrByte = (unsigned char *)ptr;
                CRC_CRC_HU = *ptrByte++;                                 // write bytes starting with MSB
                ulLength--;
                if (ulLength != 0) {
                    CRC_CRC_HL = *ptrByte++;
                    ulLength--;
                    if (ulLength != 0) {
                        CRC_CRC_LU = *ptrByte++;
                        ulLength--;
                    }
                }
                ptr = (unsigned long *)ptrByte;
            }
        #else                                                            // errata 2776 workaround
            if (ulLength != 0) {                                         // remaining bytes that didn't fit into a long word
            #if !defined _COMPILE_KEIL
                register unsigned long ull = 0;
                register int i;
            #else
                register unsigned long ull;
            #endif
                CRC_CTRL = (CRC_CTRL_TCRC_32 | CRC_CTRL_TOTR_BITS_BYTES | CRC_CTRL_FXOR); // switch to mode without swapping
            #if defined _COMPILE_KEIL
                ull = __rbit(*ptr);                                      // swap all bits of long word
            #else
                // To do - insert asm code for other compilers if required
                //
                for (i = 0; i < 32; i++) {
                    if (*ptr & (0x80000000 >> i)) {
                        ull |= (0x00000001 << i);
                    }
                }
            #endif
                CRC_CRC_LL = (unsigned char)(ull >> 24);                 // swap byte
                ulLength--;
                if (ulLength != 0) {
                    CRC_CRC_LU = (unsigned char)(ull >> 16)              // swap byte
                    ulLength--;
                    if (ulLength != 0) {
                        CRC_CRC_HL = (unsigned char)(ull >> 8);          // swap byte
                        ulLength--;
                    }
                }
            }
        #endif
            if (CRC_CRC == *ptr) {                                       // check the CRC that was calculated with that received at the end of the Ethernet frame
                // CRC-32 matches
            }
            else {
                // CRC-32 mismatch
            }
        }
‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Regards

Mark

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topic CRC for polynomial 0xedb88320 in Kinetis Microcontrollers

CRC for polynomial 0xedb88320

Re: CRC for polynomial 0xedb88320

Re: CRC for polynomial 0xedb88320