Cycle start/resume pause and external buttons problem (Mesa 7i76e card)

raychar wrote:

Missed to remind, CNC4PC's C25 breakout board socket pin outs do not match with 7i76e expansion connector pin out, i need to swap most of them when using it
 

Yes, that's expected since the C25 is expected to plug directly onto a SmoothStepper so its
connectors are on the opposite of the normal side, leading to a even/odd pin swap.

Do you have all 8 ground pins connected on each connector? You may have a ground loop
with significant HF current flowing in the cable. This can cause noise issues which will be helped
by using all grounds (the C25 plugged direct onto a SmoothStepper would be less sensitive to
ground loop issues due to the shortness of the connection.

You may (as anypugh suggested) need to debounce the signals.

>all 8 ground pins were originally connected properly, so that is not the cause from.
>I finally found my wrongdoings. I missed to notice that C25 inputs are pulled down by 4.7k ohm resistor. I additionally add a 3.3k ohm pull up resistor to make it in pull-up state. This is very bad in picking up a lot of noise. After removing them, that is, one end of the external button switch straightly connected to +5V and another end goes to input of C25 breakout board (which is pulled down), also, doing some modification in the program. The problem don't happen now.
>Anyway, i think that inputs have pull down resistor and in pull down state are much better in resistance to noise interference (?)