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fix MAD crc calculation (was wrong)

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This commit is contained in:
merlokk 2019-02-21 20:07:17 +02:00
commit 0632918a47
1 changed files with 4 additions and 3 deletions
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7
common/crc.c
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@ -99,14 +99,15 @@ uint32_t CRC8Maxim(uint8_t *buff, size_t size) {
crc_update2(&crc, buff[i], 8);
return crc_finish(&crc);
}
// width=8 poly=0x1d, reversed poly=0x?? init=0xe3 refin=true refout=true xorout=0x0000 check=0xC6 name="CRC-8/MAD"
// width=8 poly=0x1d, init=0xc7 (0xe3 - WRONG! but it mentioned in MAD datasheet) refin=true refout=true xorout=0x00 name="CRC-8/MAD"
// the CRC needs to be reversed before returned.
// init c7, poly 1d, final 0x00.
uint32_t CRC8Mad(uint8_t *buff, size_t size) {
crc_t crc;
crc_init_ref(&crc, 8, 0x1d, 0xe3, 0, true, true);
crc_init_ref(&crc, 8, 0x1d, 0xc7, 0, false, false);
for ( int i = 0; i < size; ++i)
crc_update2(&crc, buff[i], 8);
return reflect8(crc_finish(&crc));
return crc_finish(&crc);
}
// width=4 poly=0xC, reversed poly=0x7 init=0x5 refin=true refout=true xorout=0x0000 check= name="CRC-4/LEGIC"
uint32_t CRC4Legic(uint8_t *cmd, size_t size) {