crc.c

ST7540 Demo 下位机C程序

//*********************************************************************************
//*               ST 7538 DEMOBOARD SOFTWARE 	  CRC.c                             *
//*                                                                               *
//*               CRC functions                        V1.2                       *
//*********************************************************************************

/******************************************************************************/
/* Look-up table for CRC calculation */
/******************************************************************************/
/* For information: As a CRC generator polynomial following one is defined in
KNX PL132:
16 15 2
X + X + X + 1
NOTE: Following is not specified in KNX PL132 specification, but necessary to
define for precise CRC definition!!!
- CRC computation algorithm starts with zero
- it treats the data msb first
- CRC result is not complemented
Example: the sequence 01 02 03 04 05 06 07 08 has CRC value TBD. */
/******************************************************************************/
#pragma CONST_SEG NON_BAMKED

const int tableCRC[256] = {
0x0000, 0x8005, 0x800F, 0x000A, 0x801B, 0x001E, 0x0014, 0x8011,
0x8033, 0x0036, 0x003C, 0x8039, 0x0028, 0x802D, 0x8027, 0x0022,
0x8063, 0x0066, 0x006C, 0x8069, 0x0078, 0x807D, 0x8077, 0x0072,
0x0050, 0x8055, 0x805F, 0x005A, 0x804B, 0x004E, 0x0044, 0x8041,
0x80C3, 0x00C6, 0x00CC, 0x80C9, 0x00D8, 0x80DD, 0x80D7, 0x00D2,
0x00F0, 0x80F5, 0x80FF, 0x00FA, 0x80EB, 0x00EE, 0x00E4, 0x80E1,
0x00A0, 0x80A5, 0x80AF, 0x00AA, 0x80BB, 0x00BE, 0x00B4, 0x80B1,
0x8093, 0x0096, 0x009C, 0x8099, 0x0088, 0x808D, 0x8087, 0x0082,
0x8183, 0x0186, 0x018C, 0x8189, 0x0198, 0x819D, 0x8197, 0x0192,
0x01B0, 0x81B5, 0x81BF, 0x01BA, 0x81AB, 0x01AE, 0x01A4, 0x81A1,
0x01E0, 0x81E5, 0x81EF, 0x01EA, 0x81FB, 0x01FE, 0x01F4, 0x81F1,
0x81D3, 0x01D6, 0x01DC, 0x81D9, 0x01C8, 0x81CD, 0x81C7, 0x01C2,
0x0140, 0x8145, 0x814F, 0x014A, 0x815B, 0x015E, 0x0154, 0x8151,
0x8173, 0x0176, 0x017C, 0x8179, 0x0168, 0x816D, 0x8167, 0x0162,
0x8123, 0x0126, 0x012C, 0x8129, 0x0138, 0x813D, 0x8137, 0x0132,
0x0110, 0x8115, 0x811F, 0x011A, 0x810B, 0x010E, 0x0104, 0x8101,
0x8303, 0x0306, 0x030C, 0x8309, 0x0318, 0x831D, 0x8317, 0x0312,
0x0330, 0x8335, 0x833F, 0x033A, 0x832B, 0x032E, 0x0324, 0x8321,
0x0360, 0x8365, 0x836F, 0x036A, 0x837B, 0x037E, 0x0374, 0x8371,
0x8353, 0x0356, 0x035C, 0x8359, 0x0348, 0x834D, 0x8347, 0x0342,
0x03C0, 0x83C5, 0x83CF, 0x03CA, 0x83DB, 0x03DE, 0x03D4, 0x83D1,
0x83F3, 0x03F6, 0x03FC, 0x83F9, 0x03E8, 0x83ED, 0x83E7, 0x03E2,
0x83A3, 0x03A6, 0x03AC, 0x83A9, 0x03B8, 0x83BD, 0x83B7, 0x03B2,
0x0390, 0x8395, 0x839F, 0x039A, 0x838B, 0x038E, 0x0384, 0x8381,
0x0280, 0x8285, 0x828F, 0x028A, 0x829B, 0x029E, 0x0294, 0x8291,
0x82B3, 0x02B6, 0x02BC, 0x82B9, 0x02A8, 0x82AD, 0x82A7, 0x02A2,
0x82E3, 0x02E6, 0x02EC, 0x82E9, 0x02F8, 0x82FD, 0x82F7, 0x02F2,
0x02D0, 0x82D5, 0x82DF, 0x02DA, 0x82CB, 0x02CE, 0x02C4, 0x82C1,
0x8243, 0x0246, 0x024C, 0x8249, 0x0258, 0x825D, 0x8257, 0x0252,
0x0270, 0x8275, 0x827F, 0x027A, 0x826B, 0x026E, 0x0264, 0x8261,
0x0220, 0x8225, 0x822F, 0x022A, 0x823B, 0x023E, 0x0234, 0x8231,
0x8213, 0x0216, 0x021C, 0x8219, 0x0208, 0x820D, 0x8207, 0x0202 };
//#pragma CONST_SEG DEFAULT  
//*******************************************************************************

/*******************************************************************************
* Module: void dll_CalcCRC(char *buf, unsigned char n)
*
* Description:
* This function generates the 16 bit CRC	 16  15  2
* using the following polynom: 				X + X + X + 1
* Precise CRC computation algorithm definition:
* - CRC computation algorithm starts with zero
* - it treats the data msb first
* - CRC result is not complemented
*
* Returns: calculated CRC value
*
* Global Data:
* tableCRC[256] - look-up table for 16 bit CRC computation
*
* Arguments:
* *buffer - pointer to buffer to be calculated
* n - length of the buffer
*******************************************************************************/
//#pragma NO_OVERLAP
unsigned int dll_CalcCRC(unsigned char *buf, unsigned char n)
{
#pragma DATA_SEG APP_RAM
unsigned int crc = 0;
#pragma DATA_SEG DEFAULT

while (n--) 
crc = tableCRC[((crc>>8) ^ *buf++) & 0xFF] ^ (crc << 8);
	return (crc);
}
/*******************************************************************************
* CRC for one byt    
* Module: unsigned char CRC(unsigned char char_in,unsigned char crc_in, char num)
*
* Description:
* This function generates the 8 bit CRC  6   5   4   3
* using the following polynom: 			X + X + X + X + 1
* Enter: data byte and its CRC byte or 0 for calculating of CRC's byte
* Returns: calculated syndrom or CRC value
* This function can be used for calculating CRC or syndrom. For calculating of CRC 
* enter in "char_in" data byte and in "crc_in" enter "0". For calculating of syndrom 
* enter in "char_in" data byte and in "crc_in" enter CRC of data byte. If resoult will 
* be "0" it means that transfered data byte and its CRC byte are not affected. In other 
* case use resoult syndrom like index for CorrectTable to find corection integer number
* Correction can be done by xor int from table with int compesed with data byte and its CRC
*
				uni.crc_int = CorectTab[syndrom];                         
				SPI_Buffer[index+0] ^= uni.crc_char[0]; 
				SPI_Buffer[index+1] ^= uni.crc_char[1]; 
*******************************************************************************/  
unsigned char CRC(unsigned char char_in, unsigned char  crc_in, char num)
{
#pragma DATA_SEG APP_RAM
 union {
  unsigned char _char[2]; 
  unsigned int _int; 
 } _uni;
 
 _uni._char[0]  = char_in;
 _uni._char[1]  = crc_in;
 
 while (num--) { 
  	 if (_uni._char[0] & 0x80) 
 		_uni._char[0] = _uni._char[0] ^ 0xf2;
	 _uni._int = _uni._int << 1;	 
 }
 return (_uni._char[0]);
}
//********************************************************************************
// Correction table. The table is used char Check_frame(void) for correction message
// which has wrong FCS. The function is able corrected folloving bit error in byte
// 0000 0001, 0000 0011, 0000 0111, 0000 1111 and any shifted combination of this bit 
// combination (example 0000 0010 and 0000 0100 etc. or 0000 0110 and 0000 1100 etc.)  
//********************************************************************************
#pragma CONST_SEG NON_BAMKED
const unsigned int CorectTab[256] = {
0, 1, 2, 3, 4, 0, 6, 0,8, 0, 0, 0, 12, 0, 0, 0,
16, 0, 0, 0, 0, 0, 0, 0,24, 0, 0, 0, 0, 0, 0, 0,
32, 0, 0, 0, 0, 0, 0, 0,0, 0, 0, 0, 512, 0, 0, 0,
48, 0, 0, 0, 6144, 0, 0, 0,0, 0, 0, 0, 16384, 0, 0, 0,
64, 0, 0, 0, 0, 49153, 0, 0,0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,1024, 0, 0, 0, 0, 0, 0, 0,
96, 0, 0, 0, 384, 0, 0, 0,12288, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1536, 0, 0, 0,32768, 0, 0, 32771, 0, 0, 0, 0,
128, 0, 0, 0, 4096, 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, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,0, 0, 0, 0, 0, 0, 0, 0,
2048, 0, 0, 0, 0, 0, 0, 0,0, 0, 0, 0, 0, 0, 0, 0,
192, 0, 0, 0, 0, 0, 0, 0,768, 0, 0, 0, 0, 0, 0, 0,
24576, 0, 0, 0, 0, 0, 0, 0,0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 256, 0, 0, 0,3072, 0, 0, 0, 8192, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,0, 0, 0, 0, 0, 0, 0, 0
};
//#pragma CONST_SEG DEFAULT