I have already asked a question on this forum on how to get an LED light up using a pic16f59 with pickit 3 (The post can be found here). Some people have pointed out that it must be a problem connected a pickit on my pic. I wonder how to do this. As for now, I am using the pickit 3 and I am connecting the PIC as follow:

     pickit 3          PIC 
   -----------        -----
          1            14  
          2            35  
          3            5  
          4            13  
          5            12  

Also, I am connecting the VDD (pin 15 and 35) to 5V, VPP to 12V and I have also added a bypassing 1microfarad capacitor on VDD. I also connected all VSS to ground. Please refer to the PIC16F59 pinout below.

I wonder what I am doing wrong? Should I add more capacitors? I am using the right capacitor (1 micro-farad) in the first place? Please someone help. I have been doing this for more than two days with no success.

  • \$\begingroup\$ You should add a capacitor to every VDD/VSS pair. I use 100nF for decoupling caps. Have you external circuitry on your reset pin or the programming pins (pin 12, 13, 14)? This could disturb the programming. See page 68 (Appendix B) of the PICkit 3 manual. \$\endgroup\$
    – PetPaulsen
    Commented May 6, 2012 at 7:38
  • \$\begingroup\$ This is a fairly old device. Do you got an oscillator hooked up on pins 33/34? It requires this to be able to run. \$\endgroup\$
    – Hans
    Commented May 6, 2012 at 15:28

1 Answer 1


The description above is somewhat misleading. You say that Pin 14 of the Pic (Vpp/MCLR) is connected to Pin 1 of the PicKit3, which is OK. But then you say that Vpp of the Pic (which is the same Pin 14) is connected to 12V. Only one can be true.

Vpp/MCLR must be connected to the PicKit3, because it needs to control this voltage to properly enter programming mode. Also, the PIC16F59 needs a voltage between 12.5 and 13.5 volts here.

You also need to connect both Vdd pins (15+35) and GND pins (5+25) together (and use decoupling caps on both - 100nF should be enough).


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