Interrupt Mask Register
| TXRDY | Transmit Ready Interrupt Mask |
| TXEMPTY | Transmit Empty Interrupt Mask |
| ENDTX | End of Transmission Interrupt Mask |
| TXBUFE | Transmit Buffer Empty Interrupt Mask |
| RXRDY | Receive Ready Interrupt Mask |
| OVRUN | Receive Overrun Interrupt Mask |
| ENDRX | End of Reception Interrupt Mask |
| RXBUFF | Receive Buffer Full Interrupt Mask |
| CP0 | Compare 0 Interrupt Mask |
| CP1 | Compare 1 Interrupt Mask |
| TXSYN | Tx Sync Interrupt Mask |
| RXSYN | Rx Sync Interrupt Mask |