Code CR3600DPM Informations techniques télécharger pdf (Page 67)

10/29/2014

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12 Appendix: Example CRC16 C Code

The CRC16 required by Reader to Host packets (see Section 5.2) can be calculated using the following

sample C code. This CRC16 consists of two consecutive bytes, each in range [0,255] most significant byte

first. A CRC16 is calculated on each packet byte, over the entire packet, excluding the prefix and the CRC16

itself.

crc_t crc = 0;

crc = crc(crc, firstByte, firstByteSize);

crc = crc(crc, secondByte, secondByteSize)

<…>

/* crc16.h */

#ifndef crc16_h

#define crc16_h

#include <stdint.h>

#include <stddef.h>

#ifdef __cplusplus

extern "C" {

#endif

typedef uint16_t crc_t;

crc_t crc

( crc_t initialCrc

, const unsigned char* bufPtr

, size_t length

);

#ifdef __cplusplus

} // extern "C"

#endif

/* crc16.c */

#include <crc16.h>

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Code CR3600DPM Informations techniques Page 67