16f877a - grounding pin 13 or 14

[kelangfei]

I am yet another PIC newbie.

To get to the point, I have assembled a 16f877a project as per an example I found on the net - http://members.home.nl/b.vandam/lonely/pagina000.html - on a breadboard. While the project does not work as expected I did stumble over this effect: When I ground pin 13 or 14 momentarily with or without the crytal and capacitors in place, the led connected to pin 33 powers on for sometimes a second, sometimes two.

Do any thoughts occur from this clue?

Thanks
KLF

[GrandPa]

Well, could you exactly tell us what you mean by "does not work as expected", this would really help.

Also, I noted you said you build the project "as per example". But you also said that "led connected to pin 33 power on sometimes". BUT there is no led connected at pin 33 on the example?

You may have wrong capacitor size, wrong crystal or wrong config, that can explain the strange behavior of pin 13/14.

Exact schematic would help too.

J-P

[mackrackit]

Do any thoughts occur from this clue?

Pins 13 and 14 never connect to ground, the capacitors connect between these pins and ground.

[sayzer]

Something like this....


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