AD7705 reading problems

[assaad]

Hello everyone

I have connected REF+ to 2.5V
REF- to gnd

AN2- to gnd

Then on AN2+ I put voltage from 0 to 2.5 that through a POT.

So when the voltage on AN2+ is 2.5v I should get a reading of 0xFFFF. But I get about 0x5555, which is it 0xffff/3
Do I have anything wrong with the connections?

My setting of ad7705 is

[Ttelmah]

Tell us a lot more.
What PIC are you using?.
What connections for DRDY, DO, DI, RESET, CS and CLK?.
You have the required crystal?.
You are initialising the lines as in adc_init, except for the change to unipolar?.

Best Wishes

[assaad]

Thank you Ttelmah
The problem is solved.

Before using this setup, I should choose the correct channel in the communication register.