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How are you actually 'testing' this?.
You say that you only have the test meter attached to the pot. This may be the problem.
Digital potentiometers, behave significantly differently from 'real' one ...

Thankyou for all the help you are giving ckielstra.

I will test the code you have modified for me. One thing that makes me think that there is nothing wrong with the code as such is that when the ...

Anyone any other ideas why once it has passed 38K it won't go passed it again?
I've looked and looked I just can't see a problem.

Thanks

JFK

I'm measuring the 38K with a digital multimeter across the digipot terminals there is no other circuitry connected to the digipot terminals, so no influence from elsewhere.

Thanks for the code amen ...

OK thanks

The program i'm using is this one, the pot is 100K and automatically goes to midpoint at powerup unless changed by the data sent. The program i'm using is this.

#include <16f690. ...

Thanks can't see any difference in operation using the original one to the one you suggested later.

Noticed a problem and I don't know why it does this as it simulated out ok.

When I first switc ...

do you have current limiting resitors in series with your LED's?
Also try a 100nF capacitor from MCLR to ground.

JFK

Thanks

program works now surprise surprise.

I'm now on the way to the opticians to get my eye's tested.

Thanks again

JFK

Thanks for pointing out those errors , could you clarify what you mean on point 2?

The problem I have now is that the data coming out of the PIC is not changing the resistance value of the digipot. ...

OK thanks for the pointer to the command byte have to admit I was guity of not reading that far on the data sheet.

I now have this program which works ok

#include <16f690.h>
#fuses XT,NOW ...

Hi

I'm attempting to use spi for the first time.

I'm using a 16F690 and a MCP41100 digital potentionmeter.

I read a post a while ago and I have a small test program to get the spi working ...

Try removing the inverted commas in the for statement I don't think thay are needed.

So
for (i='0'; i<='9'; i++)

becomes
for (i=0; i<=9; i++)

JFK

What problems are you having?
what version is your compiler?

JFK

You need to put a delay in between selecting the adc channel and reading that channel. Time doesn't seem to be an issue s I wouls suggest a 100us delay should be ok.

JFK

If your hardware is setup to use Vcc as the Ref then i'm afraid your stuck with it. A high accuracy Vref will require hardware changes.

Try to get as tight a tolerance Regulator that supplies the ...