> >>  I am using PIC 16F84 PortA as an output and sending a nibble (0001
> >- 1111)
> >> everytime an output signal is required. The program works fine but the
> >> circuit is not giving  a clean output. Some bits that should remain
> >Low are
> >> flickering once instead (47.2ms pulse  ).

Remember that one of the Port-A pins is open collector (RA4). This might
cause flickering on HIGH output. It's not exactly what you wrote you
observed, but I thought it should be mentioned to make sure your circuit
does not suffer from that.