I have a simple problem that is making no sense at all.

Using a 16C65B at 4mhz.

Imagine if you will a simple RC circuit meant for timing that uses a 1000uf electrolytic cap to ground and a trim pot in parallel with the cap to ground for adjusting the delay.

These rc circuits are on the output pins d.0 d.1 and d.2

Using a pullup of 10k on the input pins e.0 e.1 and e.2


The code is ultra simple --

start

If porte.2 = 0 then 'channel 1
high portd.0
endif

if porte.1 = 0 then 'channel 2
high portd.1
endif

if porte.0 = 0 then 'channel 3
high portd.2
endif

goto start


Now here's what happens --

If I trigger each channel momentarily, one at a time, in any order, all is well -- the output pins each go high and stay there.

If I latch on channel 1 with a constant jumper....
channel 2 will operate fine but channel 3 will not go high if I try to trigger it.

If I latch on channel 2...
channel 3 will operate fine but channel 1 will not go high if I try to trigger it.

If I latch on channel 3...
neither channel 2 or channel 1 will operate.

NOW --

If I remove the cap from the channel trying to go high -- all is well.

??

I've tried to fix this in code -- still working on it but I can't have the program stop (pause).

I may end up figuring this out but sure would appreciate any hints.

It has to be more than just the cap being there based on the examples I gave.

THANKS KINDLY for any help.