Bonjour,
J’aimerais avoir la traduction en langage mathématique ou commun de l’algorithme calculant un CRC-16 afin de l’écrire sous Windev.Pour info, ce CRC permet de vérifier une trame entre un PC et un lecteur RFID. Le CRC-16 utilisé (codé sur 2 bytes) est une variante du standard CCITT-16 (Polynôme = 0x1021 / Valeur initiale = 0xFFFF).
Ci-dessous l’algorithme de calcul développé en C :

/** @fn void CRC_calcCrc8(u16 *crcReg, u16 poly, u16 u8Data)

* @brief Standard CRC calculation on an 8-bit piece of data. To make it

* CCITT-16, use poly=0x1021 and an initial crcReg=0xFFFF.

*

* Note: This function allows one to call it repeatedly to continue

* calculating a CRC. Thus, the first time it's called, it

* should have an initial crcReg of 0xFFFF, after which it

* can be called with its own result.

*

* @param *crcReg Pointer to current CRC register.

* @param poly Polynomial to apply.

* @param u8Data u8 data to perform CRC on.

* @return None.

*/

void CRC_calcCrc8(short *crcReg, short poly, short u8Data) {

short i;

short xorFlag;

short bit;

short dcdBitMask = 0x80;



for (i=0; i<8; i++) {

// Get the carry bit. This determines if the polynomial should be xor'd

// with the CRC register.

xorFlag = *crcReg & 0x8000;



// Shift the bits over by one.

*crcReg <<= 1;



// Shift in the next bit in the data byte

bit = ((u8Data & dcdBitMask) == dcdBitMask);

*crcReg |= bit;



// XOR the polynomial

if (xorFlag) {

*crcReg = *crcReg ^ poly;

}



// Shift over the dcd mask

dcdBitMask >>= 1;

}

}

MERCI+++ POUR VOTRE AIDE!

Configuration: Windows XP
Firefox 3.5.3