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Problem connecting 44 pin Board to an external power source

Posted: Thu Sep 24, 2009 9:04 am
by alexander70
Hi! I successfully use the kit for programming PICKIT2 Debuge Express with Flowcode. But when connecting 44 pin Demo Board to an external power source, the program stops working. And begins to work only when I hand touch the wire "-" power scheme. How to solve this problem and made to work 44 pin Demo Board from the external power source?

Respectfully, Alexander

Re: Problem connecting 44 pin Board to an external power source

Posted: Thu Sep 24, 2009 9:15 am
by Benj
Hello Alexander

That sounds strange. What kinds of external power supply are you using. Eg what voltage and current.

Does the program run only when you are touching the ground power rail or does touching other pins make the device start working?

How were you powering the device before? Via the PICkit?

Re: Problem connecting 44 pin Board to an external power source

Posted: Fri Sep 25, 2009 4:42 am
by alexander70
I connected the pin MCLR demo board through the 10k resistor on the "+" output power supply and installed an electrolytic capacitor. Power supply industrial power, precision. The program seems to work, but when I brought my hand to press the button on the demo board to manage the program, the program stops. The board responds to the capacity of my hand. How do I fix this?

Re: Problem connecting 44 pin Board to an external power source

Posted: Fri Sep 25, 2009 9:20 am
by Benj
This seems strange that the program works until you go near it.

Perhaps the Microchip forum would be a better place for your questions as they know the exact schematic of the board and could maybe suggest the cause of the problem.

I can only think that maybe your voltage is too low or the electrolytic is too small also maybe you could add some 100n ceramic caps to the supply rails close to the chip to eliminate any high frequency noise getting to the device.