Shift Register Port Expander, lsrio16 comp

yes I have to build something like that

Nice

After I had everything there, I equipped a new board.
A first test with wire bridges at the inputs worked.

Let's see if it also works in the panel

the new board sits in the panel, but strangely still have the same error pattern
so some buttons always work, some don't.
The faulty inputs are exactly the same with the new board as with the first board.

do not think that the error is in the hardware.

I tried to understand the logic of the shifter with the HalScope, but did not understand anything.

Now I tried to change the shift period and update time in the component (wiki.linuxcnc.org/uploads/lsrio16.comp).
I always recompiled it.

also without success.

Translated with www.DeepL.com/Translator (free version)

I would try adding a series resistor (say 1K) and a small capacitor (say 1000 pF) to ground
on the shift clock line at the input to the Schmitt trigger. The input shift register parts are very fast
(typically 96 MHz shift clock @ 5V) and any ringing/undershoot on the shift clock line is liable to
double clock the register. A RC filter(the 1K R and 1000 pF C) followed by the Schmitt trigger will clean
up any ringing/crosstalk SI issues with the parallel port signals.

YEAH

I had only 220pf there, so I made 2 RC filters with 2x220pF parallel and 1K resistor at SCK and RCK.

Now runs perfectly

Thank you very much,
Werner