30.2 Overview

The Unified Program and Debug Interface (UPDI) is a proprietary interface for external programming and on-chip debugging of a device.

The UPDI supports programming of nonvolatile memory (NVM) space; FLASH, EEPROM, fuses, lockbits, and the user row. In addition, the UPDI can access the entire I/O and data space of the device. See the NVM controller documentation for programming via the NVM controller and executing NVM controller commands.

Programming and debugging are done through the UPDI Physical interface (UPDI PHY), which is a one-wire UART-based half duplex interface using a dedicated pin for data reception and transmission. Clocking of UPDI PHY is done by the internal oscillator. The UPDI access layer grants access to the bus matrix, with memory mapped access to system blocks such as memories, NVM, and peripherals.

The Asynchronous System Interface (ASI) provides direct interface access to On-Chip Debugging (OCD), NVM, and System Management features. This gives the debugger direct access to system information, without requesting bus access.