TSEL=PRSCH0
USART Trigger Control register
| TSEL | Trigger PRS Channel Select 0 (PRSCH0): PRS Channel 0 selected 1 (PRSCH1): PRS Channel 1 selected 2 (PRSCH2): PRS Channel 2 selected 3 (PRSCH3): PRS Channel 3 selected | 
| RXTEN | Receive Trigger Enable | 
| TXTEN | Transmit Trigger Enable | 
| AUTOTXTEN | AUTOTX Trigger Enable |