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FIX: @marshmellow found out that the CRC-8/Maxim was not always giving the right checksum. Change POLY from 0x31 -> 0x8C

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iceman1001 2015-03-12 20:33:36 +01:00
commit a8cd503dd5
2 changed files with 5 additions and 7 deletions
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8
common/crc.c
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@ -42,13 +42,11 @@ uint32_t crc_finish(crc_t *crc)
return ( crc->state ^ crc->final_xor ) & crc->mask; return ( crc->state ^ crc->final_xor ) & crc->mask;
} }
int CRC8Maxim(uint8_t *buff, size_t size ) { uint32_t CRC8Maxim(uint8_t *buff, size_t size) {
crc_t crc; crc_t crc;
crc_init(&crc, 8, 0x31, 0x00, 0x00); crc_init(&crc, 9, 0x8c, 0x00, 0x00);
crc_clear(&crc); for ( uint8_t i = 0; i < size; ++i){
for ( int i=0; i < size; ++i){
crc_update(&crc, buff[i], 8); crc_update(&crc, buff[i], 8);
} }
return crc_finish(&crc); return crc_finish(&crc);

2
common/crc.h
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@ -38,7 +38,7 @@ extern void crc_clear(crc_t *crc);
extern uint32_t crc_finish(crc_t *crc); extern uint32_t crc_finish(crc_t *crc);
// Calculate CRC-8/Maxim checksum // Calculate CRC-8/Maxim checksum
int CRC8Maxim(uint8_t *buff, size_t size ); uint32_t CRC8Maxim(uint8_t *buff, size_t size );
/* Static initialization of a crc structure */ /* Static initialization of a crc structure */
#define CRC_INITIALIZER(_order, _polynom, _initial_value, _final_xor) { \ #define CRC_INITIALIZER(_order, _polynom, _initial_value, _final_xor) { \