CMD_RX_DISABLE
WR1(sc, PSC_CR, CMD_TX_DISABLE | CMD_RX_DISABLE);
PSC_WRITE_1(sc, PSC_CR, CMD_TX_DISABLE | CMD_RX_DISABLE);
bus_space_write_1(iot, ioh, PSC_CR, CMD_TX_DISABLE | CMD_RX_DISABLE);