SSCR1_RFT
chip->threshold = (SSCR1_RxTresh(rx_thres) & SSCR1_RFT) |
mask = SSCR1_RFT;
| SSCR1_RFT | SSCR1_TFT | SSCR1_MWDS \
mask |= SSCR1_RFT;
SSCR1_RWOT | SSCR1_TRAIL | SSCR1_TFT | SSCR1_RFT);