Using in circuit programming PINs for I/O

[camerart]

Hi,
Is it ok to use the two ICSP PINs IN and OUT (RB6 and 7) for normal use if they are used also for programming?

Camerart

 

[Les Jones]

Yes, providing that whatever is connected to them does not load the programming signals during programming.

Les.

 

[camerart]

Yes, providing that whatever is connected to them does not load the programming signals during programming.

Les.

Hi L,

I thought as much, but needed confirmation, thanks.

C.

 

[Nigel Goodwin]

Yes it's fine, depending on exactly what you're doing with the pins - I often allocate a debugging serial port to them (an FTDI board connected to them doesn't affect the programming.).

 

[camerart]

Yes it's fine, depending on exactly what you're doing with the pins - I often allocate a debugging serial port to them (an FTDI board connected to them doesn't affect the programming.).

Hi N,
I want to use them for chip/selects so they will be set to output.
C

 

[mastero]

Isolate them from the main circuit with 10E resistor and you will be fine.

 

[camerart]

Isolate them from the main circuit with 10E resistor and you will be fine.

Hi M,
Can you clarify please, and what is a 10E resistor?
C

 

[Nigel Goodwin]

I presume it's 10 ohm?, the suffix E is used by various non-English speaking countries.

 

[Pommie]

Just be aware that the chips that the CS pins are controlling will get randomly selected during programming.

Mike.

 

[JimB]

As a quick an dirty solution, I often put a DIP switch so that I can simply isolate the PIC pins and the ICSP connector from the rest of the circuit.

Look at this picture:
https://www.electro-tech-online.com...tor-revisited.150114/#lg=post-1287100&slide=0
in this thread:
https://www.electro-tech-online.com/threads/dds-signal-generator-revisited.150114/#post-1287100

The DIP switch and the ICSP connector can be seen by the end of the PIC.

When I need to program the chip, I just flick the switches to the open position.
To run the program, unplug the PICKit and close the switches.
Maybe not the most efficient method, but it suits me, and I have plenty of DIP switch packs on hand.

JimB

 

[dknguyen]

You can, but I don't unless absolutely forced to because not being able to program a chip is a game breaking scenario. Also lets you reflash and try your code without needing to disconnect everytime and lets you use the debugger uf you have one.

 

[Pommie]

Whilst developing you can often use a bigger chip from the same family and use conditional code so it'll compile for either chip.

Mike.

 

[camerart]

Hi,
Thanks for the comments, all noted.

I'll try direct connections, then remind me if I report problems please.

Thanks, C.

 

[Nigel Goodwin]

Hi,
Thanks for the comments, all noted.

I'll try direct connections, then remind me if I report problems please.

Thanks, C.

As most of us have said, it's perfectly OK to use the programming pins for I/O, as long as you're careful what you connect them to - as I've already mentioned, I often use them as serial I/O for debugging purposes - an FTDI module connected to them doesn't upset the programming, nor does the programming upset the FTDI.