#include "mbed.h"

DigitalOut CS(PTA17);
SPI spi(PTD2, PTD3, PTD1);
int value;
int main() {
    // Setup the spi for 8 bit data, high steady state clock,
    // second edge capture, with a 1MHz clock rate
    spi.format(7,3);
    spi.frequency(1000000);

    while(1) {
        //basically just ramp the wiper up and down the full range
    //but the upwards ramp is deliberately faster than the downwards ramp
     
    for (int level = 0; level <= 127; level++)
    {
      //take the SS pin low to select the chip:
      CS = 0x00;
      //send in the address and value via SPI:
      spi.write(0);
      spi.write(level);
      // take the SS pin high to de-select the chip:
      CS = 0xFF;        
      //increase this number to slow things down
      //(10000) is a good number if you want to see the LED pulsing nicely
      wait_us(100); 
    }
     
    for (int level = 127; level >= 0; level--)
    {
     //take the SS pin low to select the chip:
      CS = 0x00;
      //send in the address and value via SPI:
      spi.write(0);
      spi.write(level);
      // take the SS pin high to de-select the chip:
      CS = 0xFF;        
      //increase this number to slow things down
      //(20000) is a good number if you want to see the LED pulsing nicely
      wait_us(200);
    }
    
   }
 
}