Loading PIC micro programming pins ICSPDAT and ICSPCLK

[treez]

Hi,
We are using PIC16F1503. We need to use one of the programming pins, either ICSPDAT or ICSPCLK in the circuit to turn on a high Z input. The pickit3 programmer doesn’t tell what is the maximum current capability of the icspdat or icspclk pins. Do you know it?

None of the documentation tells it…
PIC ICSP
https://ww1.microchip.com/downloads/en/devicedoc/31028a.pdf
Pickit3
https://www.sparkfun.com/datasheets/Programmers/PICkit_3_User_Guide_51795A.pdf

 

[FvM]

You are asking about PIC ICSP pins (the specs are of course in the data sheet) or programmer rating?

 

[treez]

Programmer rating

 

[FvM]

The programmers are rated to work with the suggested ICSP circuits. Microchip did publish e.g. PICkit2 schematic in the respective user manual. It's particularly specified that the external circuit for cloack and data line shouldn't implement pull-up resistors or larger capacitive load.

 

[treez]

thanks, we are wondering if we can just get away with a 1k resistor to isolate the ICSPDAT pin from the external circuitry?...it would mean the ICSPDAT needing to be able to source some 3mA...which doesnt seem like much so it should be ok?

 

[Aussie Susan]

When you use the programming pins as ordinary GPIOs then you can do what you want with them. However, when you want to use them as programming pins then they should be unloaded.
You can achieve this by taking the components used for normal IO out of circuit when you are trying to program the MCU but this can be more trouble than it is work - except perhaps during the code development with a prototype board.
If you are *VERY CAREFUL* and stay within the published limits (as others have pointed out they are all in the documentation) the you can add pull-up and pull-down resistors etc. and still be able to program the MCU bu that is up to you.
Susan