🚀 go-pugleaf

When I implemented the monitor download command, I considered the
various popular CRC codes.  I chose the one I did because I thought
it was compatible with both Minix and CCITT.  CCITT is definitely
the wave of the future -- the organizations behind it have far more
clout than the people using CRC16.

I am disappointed to hear that the Minix people blew it when they
implemented their CRC -- that it is not really CCITT.  My preference,
however, is to try to convince them to fix their code and bring
it into conformance.  By the way, does anyone know what POSIX
specifies for the "sum" command?  Is there a POSIX "crc" command?

I used a bit serial algorithm to save ROM space (no table required)
and because download time was dominated by the serial port throughput.
I like the small table size used by the posted CRC16 routine.

Bruce Culbertson