At 09:07 AM 8/30/2001 -0400, you wrote:
My first thought would not be to
use a processor at all. I would run
the 50 inputs to 50 open collector buffers pulling down a resistor
network. Something like a R2R network but it might be simpler as
you
don't have to distinguish when multiple lines are low together.
Finally
use an op amp to buffer and filter the output.
Sherpa Doug
Since the lines are fired in a fixed sequence one at a time, it might be
easier to just put open collector buffers on the odd numbered inputs and
tie all outputs together. This will give a single input that tells
whether the line number is even or odd and the processor can count up or
down every time the even/odd line changes. Line 1 and 2 could be
tied to additional inputs in order to allow the processor to lock
onto the line number and determine whether to count up or down. The
processor would not be able to determine the line number and direction
until the line number reaches line 1 or 2, but this may be acceptable if
this is a case where the processor can be programmed to not do anything
until after a lock has occurred.
Bob Buege