Interrupt mask register
| FIFO_NOTEMPTY_INTEN | Interrupt mask of FIFO_NOTEMPTY_INT. Set 1 to enable the interrupt. |
| FIFO_HFULL_INTEN | Interrupt mask of FIFO_HFULL_INT. Set 1 to enable the interrupt. |
| FIFO_FULL_INTEN | Interrupt mask of FIFO_FULL_INT. Set 1 to enable the interrupt. |
| SCAN_INTEN | Interrupt mask of SCAN_INT. Set 1 to enable the interrupt. |