Debugging

@TODO @TODO @TODO @TODO @TODO @TODO @TODO @TODO

Braindump: Debugging can happen on a lot of levels: "Playing with settings", using the M2M debug console via JTAG, Vivado ILA, etc. etc.

Here is a comment from MJoergen from a Skype conversation that we should add here somewhere:

On another note, I had big troubles debugging this issue with the ILA (Internal Logic Analyzer). Every time I tried to view a waveform, no data appeared. Strange behaviour.

After a lot of struggle I finally found the solution: When connecting via the Hardware Manager, the don't use autoconnect. Instead, manually add a new server, and adjust the JTAG frequency to 5 MHz. Then everything works. The key issue is that the JTAG frequency has to be less than a third of the frequency of the signals being analysed. In the case of the Galaga core, the signal frequency is 18 MHz, hence the JTAG frequency should be less than 6 MHz. For the C64 core, the main clock frequency is 32 MHz so the problem isn't noticed there.

This is something to add to the M2M documentation, maybe under a section called "Debugging":

https://support.xilinx.com/s/article/63292?language=en_US