KCS_OBF
if ((v & (KCS_OBF | KCS_STATE_MASK)) == (KCS_OBF | KCS_WRITE_STATE))
sts = kcs_wait(sc, KCS_IBF | KCS_OBF, KCS_OBF, "read_data");
printf(" OBF: %2x\n", v & KCS_OBF);