Re: [PIC} Spontaneous resets

I have tracked the problem down to a relay in an auxiliary unit which
operates at the same time as the door.
It lacked a snubber diode.  Fitting one solves the problem.
Presumably it was generating enough EMI to banjax the PIC
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak                           Phone: 01663 733236
Derbyshire                eMail: [email protected]
SK23 7ND          web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*


On Sun, 27 Apr 2025 at 14:08, Allen Mulvey <[email protected]> wrote:

> I had a similar problem with an ESP device rebooting whenever a Doppler
> radar unit was triggered. Isolating and filtering the DC supply resolved
> the issue. I would also consider keeping the reset pin but put a
> capacitor on it and possibly a weak pullup.
>
> Allen Mulvey
>
> On 4/27/2025 8:47 AM, David C Brown wrote:
> > I have the |MCLR pin of the PIC configured as an input so that there is
> no
> > external reset.
> > The connection between the unit and the display in the house is over
> copper
> > using CAN bus transceivers.
> > __________________________________________
> > David C Brown
> > 43 Bings Road
> > Whaley Bridge
> > High Peak                           Phone: 01663 733236
> > Derbyshire                eMail:[email protected]
> > SK23 7ND          web:www.bings-knowle.co.uk/dcb
> > <http://www.jb.man.ac.uk/~dcb>
> >
> >
> >
> > *Sent from my etch-a-sketch*
> >
> >
> > On Sun, 27 Apr 2025 at 12:26, Jason White<
> [email protected]>
> > wrote:
> >
> >> I'd guess the unit is interfering with itself when it transmits a
> response.
> >> If that is the case, typical EMI guidelines apply.
> >>
> >> I'd suppose that your prototype might lack a ground plane, and the reset
> >> line (or something similar) is probably vulnerable to coupling into the
> >> signal produced by your radio transmitter. Moving objects in the near
> field
> >> affect the amount of coupling (capacitive, etc.).
> >>
> >> --
> >> Jason White
> >> --
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