Channel Status Register
| RXRDY | Receiver Ready (cleared by reading US_RHR) |
| TXRDY | Transmitter Ready (cleared by writing US_THR) |
| RXBRK | Break Received/End of Break (cleared by writing a one to bit US_CR.RSTSTA) |
| OVRE | Overrun Error (cleared by writing a one to bit US_CR.RSTSTA) |
| FRAME | Framing Error (cleared by writing a one to bit US_CR.RSTSTA) |
| PARE | Parity Error (cleared by writing a one to bit US_CR.RSTSTA) |
| TIMEOUT | Receiver Timeout (cleared by writing a one to bit US_CR.STTTO) |
| TXEMPTY | Transmitter Empty (cleared by writing US_THR) |
| ITER | Max Number of Repetitions Reached (cleared by writing a one to bit US_CR.RSTIT) |
| NACK | Non Acknowledge Interrupt (cleared by writing a one to bit US_CR.RSTNACK) |
| RIIC | Ring Indicator Input Change Flag (cleared on read) |
| DSRIC | Data Set Ready Input Change Flag (cleared on read) |
| DCDIC | Data Carrier Detect Input Change Flag (cleared on read) |
| CTSIC | Clear to Send Input Change Flag (cleared on read) |
| RI | Image of RI Input |
| DSR | Image of DSR Input |
| DCD | Image of DCD Input |
| CTS | Image of CTS Input |
| MANERR | Manchester Error (cleared by writing a one to the bit US_CR.RSTSTA) |