Hi Drew, i'm a little bit confused, you are using a
standard RC type servo, driven from a PIC, doesn't
the servo have it's own power wire and the PIC just
provide the "control" signal?? Why do you mention
high currents from the PIC? Can you also provide more
info about the power supply to the servo and PIC, are
they the same, etc?
-Roman



Drew Vassallo wrote:
>
> I'm using a 16C71 on a project, but as it is a very old project, I have some
> instances of poor electrical design :)  One instance of this has RB5
> directly driving a normal radio control servo, which consumes much current
> (I believe somewhere around 300mA, but I haven't measured it).  It seems to
> work fine with the 16C71, but when I switch my code over to a 16C715, the
> chip itself becomes VERY sensitive to lower supply voltages, somewhere
> around 5.10V and below.  If I move the servo too fast, the chip often
> resets, or sometimes just pauses for a moment, then continues with normal
> operation.  I think this is because the servo draws more current when it is
> in rapid motion.
>
> I guess my question is more of a request for affirmation, but could the high
> current draw directly from the pin be causing this intermittancy?  Have I
> possibly damaged the PIC in any way permanently?  I will, of course, add a
> transistor to drive the servo, but I guess if there are other problems, or
> if this isn't the cause of the intermittancy, I'd like to know what they
> might be, anyway.
>
> I'm thinking that maybe the "newer" hardware design of the 16C715 has
> resulted in a, shall we say, "more economical" construction and is more
> sensitive to out-of-spec conditions than the 16C71.

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics