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Need to load the program without removing the IC from the circuit board [Go to first

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venkates2218

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Hello friends,
Please refer the image.
I tried to connect the PICKIT2 to load the program into controller without removing IC from the main board.
By this circuit when I tired to connect the PICKIT 2,it showing VDD target mismatching.

I powered the main board at the time of loading the program.But it not working.
I need to load the program into IC without removing the IC from the main board.
How to solve this issue..?
 

This is clearly explained in the Pickit 2 documentation, including examples of how to make your design ICSP 'friendly'.
You can also tell Pickit 2 to use VDD from the target design so it doesn't clash with it's internal supply.

Brian.
 

Your circuit seems to meet the requirements for ICSP interface to work with live circuit, except if you have not mounted the Jumpers.
 

I would be cautious of the capacitor from MCLR/VPP to ground. Adding it can delay the rise of VPP and the PIC may not see the initial programming instruction.

Also be aware that you have to use high voltage programming in that configuration. If you want to use LVP you need to connect the PGM pin as well.

Brian.
 

betwixt said:
I would be cautious of the capacitor from MCLR/VPP to ground. Adding it can delay the rise of VPP and the PIC may not see the initial programming instruction.

Also be aware that you have to use high voltage programming in that configuration. If you want to use LVP you need to connect the PGM pin as well.

Brian.
Click to expand...

That means have to remove the capacitor between the MCLR to GRND..?
 

Maybe not remove it. It depends why it was put there in the first instance. If the design requires a short delay after power-up before releasing reset, it may be there to provide it. MCLR will rise slower than +5 because of the time it takes to charge the capacitor through R15. If the delay isn't needed you can probably not fit the capacitor at all, otherwise add a resistor (~1K) between the PIC and R15/C4 and connect 'RST' directly to PIC pin 1. The new resistor will isolate the capacitor from the programming voltage.

Brian.
 

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