Interrupt Enable Register
| RXPIE | RXP Interrupt Enable |
| TXPIE | TXP interrupt enable |
| DPXPIE | DXP interrupt enabled |
| EOTIE | EOT, SUSP and TXC interrupt enable |
| TXTFIE | TXTFIE interrupt enable |
| UDRIE | UDR interrupt enable |
| OVRIE | OVR interrupt enable |
| CRCEIE | CRC Interrupt enable |
| TIFREIE | TIFRE interrupt enable |
| MODFIE | Mode Fault interrupt enable |