| 31-16 | Reserved | 0 | Reserved. The reserved bit location is always read as 0. A value written to this field has no effect. |
| 15-4 | IEn | | Interrupt enable. An interrupt triggers interrupt processing only if the corresponding bit is set to 1. |
| 0 | Interrupt is disabled. |
| 1 | Interrupt is enabled. |
| 3-2 | Reserved | 0 | Reserved. The reserved bit location is always read as 0. A value written to this field has no effect. |
| 1 | NMIE | | Nonmaskable interrupt enable. An interrupt triggers interrupt processing only if the bit is set to 1. |
| The NMIE bit is cleared at reset. After reset, software must set the NMIE bit to enable the NMI and to allow INT15-INT4 to be enabled by the GIE bit in CSR and the corresponding IER bit. The NMIE bit cannot be cleared manually; a write of 0 has no effect. The NMIE bit is also cleared by the occurrence of an NMI. |
| 0 | All nonreset interrupts are disabled. |
| 1 | All nonreset interrupts are enabled. |
| 0 | Reserved | 1 | Reserved. The reserved bit location is always read as 1. A value written to this field has no effect. |