ATtiny85 and ATtiny84 DIY Programming Shield

To program an ATtiny85 or ATtiny84, smaller microcontroller brothers to the ATmega328 used in the Arduino, you can use a dedicated ISP programmer, or breadboard the chips and use an Arduino. I used the latter technique, but as I wanted an easier and more reliable way to work with a handful of chips for multiple projects, I decided to build my own programmer shield.

The Omega-MP, which I bought on eBay, is a great shield to program the ATtiny85 (and many other chips) but didn't support the ATtiny84, so my shield here will support only the ATtiny85 and 84.

Here's a Fritzing diagram of how it's wired. Ignore the labeling of the 14-pin connector. That should represent the 14-pin DIP of the ATtiny84. Pin 1 for both chips is to the left and down (yellow lead on the 85 and red on the 84). The Fritzing program didn't have an exact representation of the prototyping shield I used, so the actual wiring and the diagram will be different in practice. I used a cheap prototyping shield that's readily available on Amazon or other retailers' websites. Use a 10uF capacitor between the ground and reset pin of the host Arduino.

Here's the pinout diagram for the chips: ATtiny Pinouts and ISP Guide

I followed the linked diagram to initially breadboard my chips and then to wire up the shield. I used DIP sockets for the completed shield, but ZIF sockets would probably work well too (but take up a lot more room).

Here's my completed shield, with crappy soldering and all!

Completed Shield on an UNO R3

Top View

Bottom View

I ran the wires for the ATtiny84's 14-pin DIP socket on the bottom, tying them into the Arduino pins. I then routed the ATtiny85's 8-pin DIP socket on top, tying them in to the shared pins alongside the 14-pin socket.

This shield will program one (at a time, won't do two chips at once) ATtiny85 or ATtiny84. It'll also work with related chips from those families, but I don't know why you'd want to use an ATtiny25 or 45, or the 24 or 84 as the price difference at the hobbyist level is nil, but since they are pin identical to their siblings with more memory, they will work.