Interrupt Mask Register
| RDRF | Receive Data Register Full Interrupt Mask |
| TDRE | SPI Transmit Data Register Empty Interrupt Mask |
| MODF | Mode Fault Error Interrupt Mask |
| OVRES | Overrun Error Interrupt Mask |
| ENDRX | End of Receive Buffer Interrupt Mask |
| ENDTX | End of Transmit Buffer Interrupt Mask |
| RXBUFF | Receive Buffer Full Interrupt Mask |
| TXBUFE | Transmit Buffer Empty Interrupt Mask |
| NSSR | NSS Rising Interrupt Mask |
| TXEMPTY | Transmission Registers Empty Mask |
| UNDES | Underrun Error Interrupt Mask |