The Adafruit UPDI Friend is a compact USB serial programmer for ATtiny microcontrollers that use the UPDI (Unified Program and Debug Interface) protocol. Built around the CH340E USB serial converter with USB Type-C, it provides reliable cross-platform programming with switchable 3V or 5V power and logic levels.

A built-in 1K loop-back resistor between the RX and TX pins ensures dependable UPDI communication. Simply connect the included JST SH cable to your breadboard, select "Serial UPDI" as the programmer in the Arduino IDE with megaTinyCore, and you're ready to program.

Key Features

• Switchable 3V/5V – Select power and logic levels to match your target microcontroller
• USB Type-C – Modern connector for power and data
• CH340E USB Serial – Cross-platform driver support (Windows, macOS, Linux)
• Built-in 1K Loop-Back Resistor – Reliable UPDI communication between RX and TX
• 3V Regulator – Delivers up to 500 mA for powering your target board
• Status LEDs – Green power LED and red serial activity LED
• Breakout Pads – 0.1" spaced holes for custom wiring
• Compact Size – 26.4 × 17.8 × 4.9 mm (1.0" × 0.7" × 0.2")

Ideal For

• Programming ATtiny816, ATtiny817, ATtiny1616, and other UPDI-based ATtiny chips
• Arduino IDE projects using the megaTinyCore board support package
• Breadboard prototyping with ATtiny microcontrollers

Package Contents

• 1× Adafruit UPDI Friend (fully assembled)
• 1× JST SH cable for breadboard connection

Resources

• Adafruit UPDI Friend Guide – Setup, wiring, and usage instructions