Inexpensive function generator

It works!
It has a few bugs, but its almost done now.

The new version of the PCB has been ordered.

After talking with @Thomas Shaddack I realized it might be a good idea to add a footprint so that an atmega328 can be used as well.

After seeing how the first version performed, I'm now working on the next version which will fix the issues I had in the first one and add a few extra features.

The features are:

- External amplitude input
- External DC offset input
- External frequency and phase selector
- Sweep trigger output

The firmware is very crude at the moment, so I'll be posting the source once I have it a little bit more usable.
I'll also post the board project files once I complete the version 2.

After getting the parts that were supposed to be used in the first place, I found out that there were a couple of issues, especially with the negative voltage switcher(MC34063) which did not like at all the values found in the datasheet. I spent and evening fiddling with it and found that what works is quite different from what the datasheet shows.

The next thing I got to test was the first version of the amplifier section.
Same test as the first one, but this time with a pcb and test version of the output amplifier soldered.

And what I got was a nice 4V p-p 5MHz triangle waveform!

At that time I was still missing a lot of the components, so I ended up bodging other components that I had at hand to get the thing working somehow.

The first test I did was with a cheap evaluation module where I connected it to a old project of mine to test the firmware and see how it performs. It worked well, but lacked the output amplifier.