Thu Aug 16 10:30:49 EDT 2018
SPI works, but writing to buffer, then executing, doesn't work. What
about making this simpler: add readout first, and see what that gives.
Another thing is to clock the CPU from SPI, and pulling out debug
information that way.
Reading is not expensive: it is just routing. Writing is expensive:
it requires multiplexing at the input of a register.
So what about adding a tracer for registers? I have the probe
mechanism, so a state machine could just go through all of this.