If you convert F3 to binary, you have 11110011, wich corresponds to all bits
set (1) and RB2, RB3 clear (0). You had those bits analog, so you read a 0
from an analog pin, probably that pins was unconnected or with a low
voltage.

Try to inicialize ALL pins the very first thing your programs does. No
matter you don't use them, is a good policy to leave all non-used pins as
outputs and de-activate all analogs, camparators, pwm, ... you are not going
to use.

And always try to use pull-ups/downs and limiter resistors. I've fried some
pins even playing with leds.

2009/5/17 Mahesh P <mahesh_nkr06@yahoo.co.in>

>
> Thanks Harold/Tamas.
> setting CONFIG3H to make the PORTB[4:0] pins as Digital helped the
> simulation.
> One thing i could still not understand is:
> Why were PORTB[1:0] toggeling (PORTB was 0xF3 when a 0xFF was written to
> it) when CONFIG3H told them to come up as analog ?
>
> Regarding my board, i suppose i have zapped the pin RB5 due to static.
> This pin is just connected to a bergstick without any pullup/pulldown.
> rest of pins have some PU/PD on it.
>
> Thanks
> -mp
>
>
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