When building arduino / avr chips projects, almost everyone starts with the Arduino Uno. It’s a proven design, and there’s a lot of community support for it. The problem I have with it is that this board is not realistic for the use makers and hobbyist make of it.
The ATmega328 is a monster. 32 kilobyte of rom? 23 input/output?! Is this really needed to power a 3 buttons project? If you were to make your application a real product, could you reduce the cost by simply using a more properly sized chip?
Most of the time, the answer should be yes. The guys at Arduino haven’t released a prototyping board for smaller chips unfortunately so I well… I built one.

Simply put, it is ATTiny84 mounted in an IC socket with 0.1″ headers for easy access to the pins. In addition, the header next to the chip is an AVR ISP header for easy programming of the chip. The chip is programmed using an Arduino Uno running the “Arduino as ISP” sketch.

All of this would not have been possible with the help of:
- “Programming an ATTiny w/ Arduino” from High-Low tech page
- ATtiny microcontroller support for the Arduino IDE library
So thanks to them!
2 thoughts on “Arduino on ATTiny84: a development board”
What does the capacitor do in this circuit? Are there wiring/circuit diagrams anywhere? I’m looking into using attinys in a project and I’d like to get to know them a bit more.
It’s just a decoupling cap. There’s no wiring to describe; this is just breaking out the ISP pins for programming!