ASC_RXBUF_DUMMY_RX
c = asc_in(port, ASC_RXBUF) | ASC_RXBUF_DUMMY_RX;
if (c == (ASC_RXBUF_FE | ASC_RXBUF_DUMMY_RX)) {
ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_RX;