ICSP wiring

lilimike

Member

• Feb 9, 2011

• #1

At one point I picked up this way of connecting ICSP from a datasheet and I've applied this to all of my circuits.

I've never had issues but I am wondering if I need R1,D1 and C1 unless I want to use Port A5 as an input. If I don't use A5 can I just drop those 3 components and connect MCLR directly to VPP pin of ICSP connector?

Mike

 

be80be

Well-Known Member

• Feb 9, 2011

• #2

If you set MCLR to MCLR = [OFF]

 

Last edited: Feb 9, 2011

lilimike

Member

• Feb 9, 2011

• #3

Thanks Burt,

Your response brings one more question; if I set MCLR to OFF will it interfere with R1, C1 and D1?
A quick test on breadboard shows that my circuit still works when MCLR is off while using the 3 components but just to make sure.

Mike

 

be80be

Well-Known Member

• Feb 9, 2011

• #4

If you want the pin for I/O you'll need to remove them

 

lilimike

Member

• Feb 9, 2011

• #5

Sorry, This is still not clear to me, please correct me if I am wrong.
Based on the fact that I always have an ICSP connector hooked up for the purpose of program updates.

If I use Port A5 as I/O I should keep the 3 components and set MCLR = On
If I do not use Port A5 as I/O I should remove the 3 components and set MCLR = Off

Is this correct?

Mike

 

be80be

Well-Known Member

• Feb 9, 2011

• #6

If YOU use Port A5 as I/O YOU should remove the 3 components and set MCLR = Off

 

Last edited: Feb 9, 2011

lilimike

Member

• Feb 9, 2011

• #7

Ok so since I do not use Port A5 as per my first post, I need to keep the 3 components and set MCLR = On?

sorry if I am slow tonight, could be the wine.

Mike

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Feb 10, 2011

• #8

be80be said:

If YOU use Port A5 as I/O YOU should remove the 3 components and set MCLR = Off

Click to expand...

Sorry, but I would disagree with you, under almost all circumstances the three components won't have much, or any, effect on using the pin as I/O.

However, I would remove the capacitor anyway, as it's not really required - and is the main component that 'might' have a small effect on I/O.