PC controller.

[Gordon Couger]

I have built a number of machine controlers. Non for engins but some that
were pretty well loaded. 

I have used a 68hc11 alot. Any thing you do at much speed at all has to be
reduced to a map or lookup table. The fastest thing it can do is count events
at xtal speed/4 2 or 3 MHz which will give about 1 degree at 6,000 rpm for a
8 MHz part. Now then you won'g be able to do any thing at this speed but 3 or
4 times per turn of the crank. At 4 time per rev you would have 90 machine 
cycles. So real tight code might be able to do more. If you do any divides
or multiplies your dead.

Intels 80C196 gives you a lot more room to work. They run about the same as
a 12 MHz AT. But unobtainium makes up a major part of the processor and the 
board.

I think that a fast PC would be an excelent platform for someone experianced 
with using them as a development system rather than learning a new compiler 
and CPU. 

Most printer ports will give you 16 I/O lines per card. Some are a little
strange on some cards. You can easily have 3 printer ports in a PC.

You can hook a string of SPI A/D converters to 2 wires of a printer port plus
one wire for each A/D converter.  If any wants the code I will be glad to 
email it to you.

Good luck
Gordon


Gordon Couger Senior Software Specialist
Biosystems & Agricultural Engineering Dept.  Oklahoma State Univ.
114 Ag Hall Stillwater, OK 74075
gcouger at master.ceat.okstate.edu