How to implement ICSP on PIC18F4550?

[spegoraro]

Hi all,
Firstly, thanks for all of the fantastic information on the site! I've been reading for some time.

I have just built myself the ICD2 Clone from this site and am curious as to how I will interface it to my PIC18F4550 in circuit.
I have already played with a USB bootloader based circuit but want to embed it now and have an ICSP header on board.

I'm aware that I can just hook up the pins from the header to the corresponding pins on the MCU but I would like to know how to provide isolation in order to use RB6/RB7, etc as I/O pins as well.
I have already read the Microchip TBO16 - How to Implement ICSP in PIC16F8X (I know it's not an 18F but had a go) but it doesn't say anything more useful than that isolation will be application specific.
I will mainly be dealing with TTL level IO and would love to be able to use those pins as a software UART.

Any help will be greatly appreciated!

 

[keith1200rs]

ICSP Circuit Design

I am not a PIC expert, but I am not sure what the problem is. When you unplug the ICSP cable then the pins are disconnected and free to be used as normal I/O pins aren't they? I guess I am missing something. Maybe seeing your proposed circuit would help explain the problem.

Keith.

 

[wp100]

Re: ICSP Circuit Design

Hi,

You might find some help in the ICSP section of this manual.
MODickit2 maunal is freely available on the web. Just give out the link. Thaz it..

Ouch... thats me told ...:roll: :roll:

The link is https://ww1.microchip.com/downloads/en/DeviceDoc/51553E.pdf

 

[spegoraro]

Re: ICSP Circuit Design

Awesome! That's just what I needed thankyou!