How to use the CRC module of MC56F84462？

xiaofei — Mon, 03 Aug 2015 04:08:39 GMT

I want to use the CRC module of MC56F84462 to calculate CRC-modbus 。

I have tried so many times ，but still have not get the right answer。

for example，the input data are：0xF4，0x02，0x06，0x12，and the right CRC(modbus) is 0x7910。

how can i get it？

my code is here：

CRC init：

void CRC_Init(void) {   /* CRC_CTRL: TOT=1,TOTR=1,??=0,FXOR=0,WAS=0,TCRC=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0 */   setReg32(CRC_CTRL, 0x50000000UL);        /* CRC_GPOLY: HIGH=0,LOW=0x8005 */   setReg32(CRC_GPOLY, 0x8005UL);           /* CRC_CTRL: WAS=1 */   setReg32Bits(CRC_CTRL, 0x02000000UL);    /* CRC_CRC: HU=0xFF,HL=0xFF,LU=0xEA,LL=0xA8 */   setReg32(CRC_CRC, 0xFFFFFFFFUL);         /* CRC_CTRL: WAS=0 */   clrReg32Bits(CRC_CTRL, 0x02000000UL);  }

CRC calculate code is here：

{   unsigned char temp_size=0;   unsigned char temp_i=0;   unsigned char temp_o = 0;   unsigned char *temp_p;   unsigned short temp_in;    setReg32Bits(CRC_CTRL, 0x02000000UL);   setReg32(CRC_CRC, 0xFFFFFFFFUL);   clrReg32Bits(CRC_CTRL, 0x02000000UL);   //setReg32(CRC_GPOLY,0x8005);   temp_size = data_size/2;   temp_o=0;   for(temp_i=0;temp_i<temp_size;temp_i++)   {         temp_in = (((unsigned short)(*data_buf)<<8)|*(data_buf+1));        setReg32(CRC_CRC,temp_in);        temp_o +=2;        data_buf +=2;   }   if(temp_o<data_size)   {        temp_p = (unsigned char *)&CRC_CRC;        *temp_p++ = *data_buf;   }   temp_sum = (unsigned short)(0xFFFF&getReg32(CRC_CRC));   temp_sum1 = (unsigned short)(getReg32(CRC_CRC)>>16); }

if there is some mistake ，please help me，thanks so much。

Re: How to use the CRC module of MC56F84462？

johnlwinters — Tue, 12 Jan 2016 22:30:24 GMT

The 16/32-bit code is calculated for 32 bits of data at a time. You are listing your input 8 bits at a time.

Please clarify.

Re: How to use the CRC module of MC56F84462？

johnlwinters — Wed, 27 Jan 2016 20:26:14 GMT

The IDE, CodeWarrior 10.6, comes with example programs.

One of these is for the CRC, and it shows how to calculate the CRC for the case of the 8 bit stream.

Please refer to this code as your template.

Digital Signal ControllersのトピックHow to use the CRC module of MC56F84462？

How to use the CRC module of MC56F84462？

Re: How to use the CRC module of MC56F84462？

Re: How to use the CRC module of MC56F84462？