UPDI Communication Error Handling

The UPDI contains a comprehensive error detection system that provides information to the debugger when recovering from an error scenario. The error detection consists of detecting physical transmission errors like start bit error, parity error, contention error, and frame error, to more high-level errors like access timeout error. See the PESIG bits in UPDI_STATUSB for an overview of the available error signatures.

Whenever the UPDI detects an error, it will immediately transfer to an internal error state to avoid unwanted system communication. In the error state the UPDI will ignore all incoming data requests, except if a BREAK character is transmitted. The following procedure should always be applied when recovering from an error condition.