At 09:11 AM 7/17/01 +0100, you wrote:

>Myself I've had some success by isolating the supply to the PIC via a diode
>and or resistor feeding a cap. But I'm not at all sure this is the best fix.
>One of the problems in this environment is that often the power supply is an
>RX battery pack which may only supply 4.8V which does not give a lot of room
>for manouver. So what do you guys do? I'm more of a software sort of person,
>and unfortunately this sort of problem is hard to fix in software (though
>most of my code does seem to have rather a lot of stuff to deal with
>processor resets! Wonder why...).

Are you using the internal BOR? Maybe an external one with a lower setting
would help (provided you stay within the specifications of the PIC). The
diode/cap idea is not bad. If you use a Schottky diode, the
drop is only a few hundred mV. Using a version guaranteed to operate at 2V
(at 4MHz say) could give you a fair bit of margin. It's certainly possible
to further improve on this- it would help if you have some idea of the
characteristics of the voltage drop- how low and how long.

BTW, like the other fellow, I'm a bit confused by your subject heading.
My guess is that the servo is pulling the supply voltage down and the
micro is resetting. What does this have to do with PORTB?

Best regards,
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Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Contributions invited->The AVR-gcc FAQ is at: http://www.bluecollarlinux.com
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