Author Topic: Programmed to fail  (Read 596 times)

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Offline PerranOak

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Programmed to fail
« on: March 23, 2019, 03:04:23 pm »
I have my project up and running and am going to get a PCB made.

While developing I would take the uC out of the circuit (ZIF), programme it then put it back. [PICkit3]

How do I incorporate programming for the uC when installed permanently on the PCB? Will the other components not interfere with the programming even if there is no power connected?
Some light can never be seen!
RJD
 

Offline fchk

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Re: Programmed to fail
« Reply #1 on: March 23, 2019, 03:30:33 pm »
While developing I would take the uC out of the circuit (ZIF), programme it then put it back. [PICkit3]

No, thats the wrong way. You need to implement an ICSP header in order to program the controller within the circuit.

Just read this:

https://ww1.microchip.com/downloads/en/DeviceDoc/51795B.pdf

The PGC and PGD pins should not be used otherwise if possible.

fchk
 

Offline PerranOak

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Re: Programmed to fail
« Reply #2 on: March 23, 2019, 05:26:25 pm »
Ah, thank you.

Are PGC and PGD the same as ICSPCLK and ICSPDAT?

I have these connected to the anodes of common cathode 7-seg LEDs via current limiting resistors. If I connect directly to the pins, will this be ok?
Some light can never be seen!
RJD
 

Offline fchk

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Re: Programmed to fail
« Reply #3 on: March 23, 2019, 06:39:39 pm »
Are PGC and PGD the same as ICSPCLK and ICSPDAT?

Yes, just other names

I have these connected to the anodes of common cathode 7-seg LEDs via current limiting resistors. If I connect directly to the pins, will this be ok?

If you want to play safe I STRONGLY advise you not to use PGC and PGD for anything else. The added load could disturb the programmer. If you absolutely must, use buffers to isolate the load from the PGC/PGD pins.

And keep in mind that on 8 Bit PICs (PIC10/12/16/18) MCLR can rise up to 13.5V during programming and protect logic being connected to it.

fchk
 

Offline PerranOak

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Re: Programmed to fail
« Reply #4 on: March 24, 2019, 12:12:01 pm »
Blimey, thank you very much.
Some light can never be seen!
RJD
 


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