I found this USB module that claims to work with all microcomputers so I ordered one.
Some of the guys are using these with megasquirts.

Kind of stupid putting a RS232 on there to generated a lot of weird voltages you
don't need. The module only cost $15. I would probably have that in chips, caps and
DB9 connector. It is shown in the lower right corner. The board is still 3.8 inches
by 2.5 inches 3 for $50. The hardware PWM generator, injector drivers and FETs are on
the right. The external 10 Mhz clock is the lower center. There is a divide by 1024
chip that gets it down to below 10K for the RPM count. There is also a CD4049 that
conditions the CAS for the 22 degree BTDC interrupt once per rev.

The board is a cross between a bread board and a final design. I am going to
experiment and find out what ports work for what.

Paul Lamar
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