Andy Baker wrote:
>
> This one has got me stumped, perhaps you may be able to shed some light.
>
> I have a PIC16F84 circuit to control an audio preamplifier (switching
> inputs, and displaying the result on an LCD).
>
> On breadboard, the circuit / software works fine.
>
> On transferring it to PCB, it stopped working. But, if I hold a test probe
> (or piece of wire) to RA1 (which is one of the LCD bit 6 data line), it
> works. As soon as I remove the probe, it stops working.

Is the LCD pin an open collector type output. If so the PIC input may be
floating. Place a 10K or so pullup resistor on the pin.

--
Best regards

Tony

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