Arduino REV3 and potentiometers

Hi everybody,

I’m having problems trying to control a digital potentiometer MCP4151 with my Arduino.
I’ve tried and checked everything, the card is OK, I tested a hundred different codes, but the resistance on the wire just won’t change. I tested the voltage on the POW pin and it gets stuck at 0,025V or 2,5V or 0,71V (depending on his mood I guess because I don’t change the program).

here’s the datasheet of the chip
and you can find my code and schematic view of electronique assembly.

Thanks a lot for your Help ! You’re my last hope !

test_SPI.ino (552 Bytes)

How to post images.

#include "SPI.h" // necessary library
const int ss = 10; // using digital pin 10 for SPI slave select

void setup()
  SPI.begin();    //Begins the SPI commnuication
  pinMode(ss, OUTPUT); // we use this for SS pin                           
  SPI.setClockDivider(SPI_CLOCK_DIV64);    //Sets clock for SPI communication at 8 (16/64=0.25Mhz)
  digitalWrite(ss, LOW); 

void loop()
  digitalWrite(ss, LOW);  
  digitalWrite(10, HIGH);          

How to post code and advice on how to use the forum.

Clickable link to data sheet.