LED Matrix with transistors damaging pics

Thread Starter

ozirock

Joined Jan 13, 2011
47
Hi,

I was trying to control an 5x7 LED dot matrix using a pic 16f627 with transistors. I was able to light the LED's by directly connecting transistors to ground and +5v so I'm pretty confident that side of things is okay. However when I connected a 1k resistor between each transistor and a pin on the pic and ran some simple code my pic broke and could not be reprogrammed. I think too much current was drawn through the pic but I don't know why, I'd be very grateful if someone could explain my mistake.

I had it wired like this:



Parts:

Thanks
 

debjit625

Joined Apr 17, 2010
790
Provide a proper schematic diagram of your circuit and the simple code that you ran........

Most Microchip's PIC range use Vdd,Vss,RB7,RB6 and MCLR pins to get programmed now RB7 and RB6 are one of the ports pin also, that can be used for general I/O operations.

However when I connected a 1k resistor between each transistor and a pin on the pic and ran some simple code my pic broke and could not be reprogrammed.
If any pin is damaged that might not stop the programming,but if its one of the RB7 or RB6 then it might be.....

Good luck
 

trixheim

Joined Apr 1, 2009
10
There should be a serial resistor to the LED for current limiting. I think the base resistors are too small, they should be around 10K.

Regards
Tor
 
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