This tool (flashsimu) was written to provide a test-environment
for the development of the flashprog-tool. I was using a PC with
two serial ports that were connected by a null-modem-cable.

When I had the "real" MyCPU-Compact on my desk I could simply
connect it with the PC and program the Flash-memory.
If there would be errors (but there weren't) I could be sure
that the error is not in the flashprog tool - because it was
already tested with a simulated FPGA programming interface.
