siba_crc8
static uint8_t siba_crc8(uint8_t, uint8_t);
crc1 = siba_crc8(crc1, sprom[word] & 0x00ff);
crc1 = siba_crc8(crc1, (sprom[word] & 0xff00) >> 8);
crc1 = siba_crc8(crc1, sprom[size - 1] & 0x00ff);