Let me get this straight; the PIC has no 5V power, but you have 5V power
to the LED's ?

If that's the case, then your LED's are probably turning on through the
protection diodes, which is effectively a diode between the port pin and
Vcc.

Sebastian Dols wrote:
>
> Ok, I have detected a strange behaviour in my 16f84 last nigth, and I want
> to share with you.
>
> Imagine a 16f84, ceramic resonator 1Mhz, _MCLR to Vdd, five leds in rba0:4,
> with no current limiter resistor in the led paths. portb is all input,
> interrupt in rb4:7 change (nothing strange, I think). Program coded to shift
> led blinking, period 1 sec, change of direction on portb signal. No problem
> to compile, no problem to run, all OK... But if NO 5V to  the PIC vdd pin,
> if 5V (signal) is applied to any of portb pins, all the leds in porta are
> emitting light at the same time...
>
> Someone knows what happens? I suspect about my protoboard, but there is no
> way between 5V to the leds to GND if i remove the PIC (the leds do not emit
> in that case, of course)
>
> Thanks in advance, keep on PICing.