Here is an example of a 555 timer driving a 7 segment LED display with .NET Gadgeteer. It’s an extension of my previous 7 segment LED. The setup looks like this: 
I’ve setup a 555 timer rather than write code-based timer. This allows for external control of the tick delay via an interrupt pin… and is a good example for how to wire a 555 in astable mode.
References: 555 timer: http://en.wikipedia.org/wiki/555_timer_IC
The source code is located here:
https://github.com/wbsimms/TimerCounting
As usual, pull requests are encouraged!
