HAL tests

[FFY00]

We can test the protocol implementation by implementing a custom HAL, but we should still test the HAL implementations.

I am not exactly sure how this should look like, but I think probably having a testing board with an FPGA, and a swappable child PCB for each platform.

cc @perigoso

[perigoso]

I like this, I think it's something to look into, it is however pretty complex and a project by itself