TX Buffer Double Data Extended Register
| TXDATA0 | TX Data | 
| UBRXAT0 | Unblock RX After Transmission | 
| TXTRIAT0 | Set TXTRI After Transmission | 
| TXBREAK0 | Transmit Data as Break | 
| TXDISAT0 | Clear TXEN After Transmission | 
| RXENAT0 | Enable RX After Transmission | 
| TXDATA1 | TX Data | 
| UBRXAT1 | Unblock RX After Transmission | 
| TXTRIAT1 | Set TXTRI After Transmission | 
| TXBREAK1 | Transmit Data as Break | 
| TXDISAT1 | Clear TXEN After Transmission | 
| RXENAT1 | Enable RX After Transmission |