4.4 Connection for UPDI Programming

The Unified Program and Debug Interface (UPDI) connection provides a one-wire interface for external programming and On-Chip Debugging (OCD). This section covers only the physical connection and not the details of the signal protocol or the features of the UPDI peripheral. These details are described in the UPDI - Unified Program and Debug Interface chapter.

The recommended UPDI connection has changed since its initial introduction. For this reason, both connections are described below: The initial UPDI connection layout is named UPDI Connection v1, while the newer layout is named UPDI Connection v2. The difference between the two connections is the inclusion of a RESET signal in the v2 connection.