16F777 resetting - at seemingly random times

[orjon1]

I have tried three power supplies - Using one for circuit and one for LEDS, and also using the same supply split with a voltage regulator for the PIC circuit. The LED supply is a hefty (and expense!) 12v 8.5 amp supply that should be more than adequate to power 10meters of 5050 smd RGB leds;

36watts per 5 meters - From Manufacturer
Thus 10m = 72 watts
72 / 12v = 6 amp.
I believe that calculation is correct. No smoke yet anyway...

On your suggestion, I have set PCON.2=0 (BOR = OFF) and the problem persists.

Any other ideas? I read something about PCL tables...

Many Thanks!





The LED strips have their own resistors. As I am cycling through the colours - there are only ever two colours on at the same time (interesting spectral information!).

[orjon1]

here is the circuit;

[LinkMTech]

1. Try adding 1.0uF caps to the input and output of the 5V regulator as well.
2. I would make sure the 4.7K pullup on the MCLR line has a solid connection. A MCLR left floating would also cause intermittent resets.
3. Or just disable the MCLR function (MCLR_OFF, if I remember correctly) just to be sure some unseen noise spikes are not triggering the uC reset.

[shahidali55]

Try 47ohm resistor between PWM pins and mosfet gate

[mister_e]

BOTH Vdd and BOTH Vss NEED to be connected.

[orjon1]

BOTH Vdd and Vss? Wow, that's new - I'm surprised my other projects worked at all..

Will start with that and the MCLR and see how it goes.

Thank you all.

[orjon1]

Working perfectly!

Changes made,
MCLR OFF
47ohms resistors to MOSFET's
both Vdd and Vss's connected

Have not added the cap's due to space constraints - but will do that if it plays up again.

Thank you all again.
Orjon.

[Archangel]

I thought so but was not sure enough to mention it, thanks Steve.