CRC-16/CCITT-FALSE

crc16.c

uint16_t crc16(char* pData, int length)
{
    uint8_t i;
    uint16_t wCrc = 0xffff;
    while (length--) {
        wCrc ^= *(unsigned char *)pData++ << 8;
        for (i=0; i < 8; i++)
            wCrc = wCrc & 0x8000 ? (wCrc << 1) ^ 0x1021 : wCrc << 1;
    }
    return wCrc & 0xffff;
}