Interrupt masked register
| TX_TRIGGER | Logical and of corresponding request and mask bits. |
| TX_NOT_FULL | Logical and of corresponding request and mask bits. |
| TX_EMPTY | Logical and of corresponding request and mask bits. |
| TX_OVERFLOW | Logical and of corresponding request and mask bits. |
| TX_UNDERFLOW | Logical and of corresponding request and mask bits. |
| TX_WD | Logical and of corresponding request and mask bits. |
| RX_TRIGGER | Logical and of corresponding request and mask bits. |
| RX_NOT_EMPTY | Logical and of corresponding request and mask bits. |
| RX_FULL | Logical and of corresponding request and mask bits. |
| RX_OVERFLOW | Logical and of corresponding request and mask bits. |
| RX_UNDERFLOW | Logical and of corresponding request and mask bits. |
| RX_WD | Logical and of corresponding request and mask bits. |