The UPDI stands for Unified Program and Debug Interface, but we will refer to it as the Unusually Playful Device Interfacer. This device is designed to easily program modern ATtiny chips with 3V or 5V power options, logic select, power, and transmit indicator LEDs, and a quick cable for easy breadboard insertion.

This USB serial UPDI programmer, the Adafruit High Voltage UPDI Friend, offers additional capabilities compared to our simpler UPDI version. By providing a high voltage option, it allows for a 12V pulse to be sent to the UPDI before programming. This is crucial when the chip is set to use the UPDI pin as a reset or GPIO. Additionally, it has the ability to "unbrick" chips configured for high voltage use, making it a reliable tool for resetting fuses for low voltage programming.

As for our seesaw boards, we have been working a lot with  lately. And we're often needing to program them with a  with a . But we were hankering for a nicer programmer!

This UPDI High Voltage Friend makes programming such chips very easy:

• Select between 3V or 5V power and logic - the 3V regulator can source up to 500mA to run even big projects. 
• Internal 12V boost converter with analog switch that will send a pulse to the UPDI line when the RTS pin is toggled low. 
• CH340E USB Serial converter chip with cross-platform drivers
• 1K Loop-back Resistor between RX and TX
• USB Type C for data and power connection to any computer
• JST SH cable included for quick plugging into a breadboard - you can get another or with here.
• 0.1" spaced breakout holes for custom connections.
• Green power OK LED
• Red serial activity LED
• Inspired by this  from !

We use Arduino IDE with the megaTinyCore board support package installed; simply select "Serial UPDI" as the programmer type. We use 230Kbps, but 56Kbps is also good. In order to enable the high-voltage fuses settings, you'll need to edit boards.txt to remove the # comment tag on the “UPDI/RESET PIN CONFIGURATION” lines.