Interrupt flag clear register
| PECF | Parity error clear flag |
| FECF | Framing error clear flag |
| NECF | Noise detected clear flag |
| ORECF | Overrun error clear flag |
| IDLECF | Idle line detected clear flag |
| TCCF | Transmission complete clear flag |
| CTSCF | CTS clear flag |
| CMCF | Character match clear flag |