Added interrupt service routine (ISR) support and new pin controllers with change detection

[spacepope]

Hi there,
nothing happened since a long time.
I continously enhanced the functionality for one of my personal projetcs and possibly should have done a pull request earlier - but hey, better late than never ;-)

So what's new compared to your version:

• fixed some minor errors on SpiDev
• added wide support for interrupt service routines (ISR) on PiFace. Short explanation: PiFace connects an internal wire to Raspberry Pi's GPIO25. When enabling PiFace interrupt handling on digital inputs (accessed via GPINTENB), input changes result in a change of GPIO25. So the when registering an interrupt on GPIO25 we can then query PiFace interrupt latch and pin states..
• added extended pin controllers InputPinController, InputPinGroupController and ButtonInputController with pin change detection.

You can see a small example in the ISRSampleConsole demo project.

Hope that i can make somebody else happy, who ever wants to do that kinda stuff with their PiFace on Mono..

If you have any questions, feel free to ask..

Best regards
Hannes

[mikeclayton]

Hey, sorry for not reviewing sooner - I appreciate the work you've put into this PR. Input pin interrupts were something I wanted to try to get working, but I didn't really know where to start so it's great that you've added this functionality.

Raspberry Pi / PiFace was a bit of a hobby while I had the time to play with them but I've had to put it on hold for the last couple of years due to other commitments so I've not really had time to look at this.

I'll leave the PR active, and hopefully one day I'll get around to merging it all!

Thanks again.

Mike