4.4 Connection for UPDI Programming

The Unified Program and Debugging Interface (UPDI) connection provides a one-wire interface for external programming and on-chip debugging (OCD). This section is related to the physical connection itself and not the details of the signal protocol and features of the UPDI peripheral. These details are described in the UPDI section.

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