Hi
Whilst testing my 64 based project I noticed that a finger brought up to
the quartz window caused the output leds connected (via 2003 darlintons)
to ports C and D to behave oddly. This is not caused by the oft mentioned
optical effect as the window was covered. Neither is it a decoupling
problem as each pair of supply pins has 100n across them. The supply
comes from a 78L05 and the timing is courtesy of a three terminal (4MHz)
ceramic resonator.

1) Has anyone else come across this effect.
2) Will the effect go away when I use the OTP versions.

BTW I have tried two windowed chips, both show the 'capacitive effect'.

Thanks in anticipation of any forthcoming help

Nick