MAX6900_BURST_SECOND
dt->dt_sec = bcdtobin(bcd[MAX6900_BURST_SECOND] & MAX6900_SECOND_MASK);
bcd[MAX6900_BURST_SECOND] = bintobcd(dt->dt_sec);
cmdbuf, 1, &bcd[MAX6900_BURST_SECOND], 1, 0)) != 0) {