Hi,

Below, you can find 2 circuits of ports P0 and P3 (89C668). Can I ask to judge if it's a wise idea to foresee a 'dimming' series resistor (100 0hm; protection of inputs against ESD etc) and small capacitors (100n) to ground, to filter out HF?

For port 0, there are additional 10k resistors to +5V.





Any comments (positive or negative) are highly appreciated.

Thanks in advance,

Best rgds,

--Geert