> Right now I'm testing this problem with only the PIC connected to my
> computer via serial (No motor/driver hooked up), when I get very close to
> the microcontroler with my hand it start resetting very fast (spam on ser=
ial
> communication)


Such things are usually due to "doing something wrong" or "not doing
something right".

- Floating inputs. (common)
- Gnd pins nlt grounded, Supply pins not supplied (too common)
- Reset line not properly terminated. (common)
- Lack of decoupling capacitors.(reasonably common)
- Power not being fed from where it's meant to be (rarer)
- Clock is not properly driven  and/or connected. (common enough)
- Applied voltages on pins is outside allowed limits (happens)
- Overclocking (whole or PLL section or ...) (Caveat Emptor)


In the last case, the MAX232 makes ~=3D  +/- 12V
This has the possibility of doing interesting things if it gets into the PI=
C.

If you can put the PIC into another clock mode that is known or more
likely to be "legal" it may help with diagnosis.



    Russell McMahon


On 3 June 2011 03:38, Henrique Ribeiro de Oliveira
<henrique.ro@gmail.com> wrote:
> Hello
>
> I'm using the 18f252 to receive step info from my computer and create a
> stepper-motor speed profile.
>
> There is a MAX232 on a external board for the serial communication (seria=
l
> is grounded to the computer)
> On the PIC board there is only few components to run the microcontroler a=
nd
> connectors to send the command
> Using a switching power supply with 24V output and one linear regulator t=
o
> make 5V.
>
> Right now I'm testing this problem with only the PIC connected to my
> computer via serial (No motor/driver hooked up), when I get very close to
> the microcontroler with my hand it start resetting very fast (spam on ser=
ial
> communication)
> Already tried changing power supply (used a battery, computer power suppl=
y
> and a simple DC wall adapter)
>
>
>
> One more thing, I'm using 12mhz crystal and PLL4x =A0 (overclocked to 48m=
hz)
> going to buy 10mhz crystal today to check if the clock is the problem
>
>
> Thanks in advance and sorry for any english errors.
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>

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