CAS_MAC_FIRST_COLL_CNT
bus_space_write_4(t, h, CAS_MAC_FIRST_COLL_CNT, 0);
bus_space_read_4(t, mac, CAS_MAC_FIRST_COLL_CNT);
bus_space_write_4(t, mac, CAS_MAC_FIRST_COLL_CNT, 0);