In my last post, I described a minimum configuration for an ATMEGA microcontroller, which is also used in the earlier Arduino boards, and I also explained how to program that microcontroller with an ISP. Here, I present a small all-purpose board that contains exactly that minimum configuration together with an USB-B connector. The USB connector has two purposes: First, it provides the 5V voltage as power source for the board. And, second, it is fully connected to the microcontroller, so that it can be used in combination, for example, with the V-USB library. At the end of this article I show an example for this board that implements a virtual keyboard. The board provides two programming interfaces: You can either use a 6-pin ISP, or a FTDI programmer to get your code on the microcontroller. And the last thing that I want to mention before we go deeper into the details, is that all parts of this boards (which are not so many) are through-hole parts. This means that you can easily solder the whole board without the need for costly equipment or professional soldering skills. Everything needs a name. Because they are tasty and I somehow thought of them at that moment, the board is called “Pancake“.
