tpl0501.ino

#include <SPI.h>

#define PIN_LED GPIO_NUM_4
#define PIN_VREF GPIO_NUM_25
#define PIN_MOSI GPIO_NUM_23
#define PIN_CLOCK GPIO_NUM_18
#define PIN_GAIN_EN GPIO_NUM_12
#define PIN_OFFSET_EN GPIO_NUM_14

void StartSPI()
{
  pinMode(PIN_GAIN_EN, OUTPUT);
  digitalWrite(PIN_GAIN_EN, HIGH);
  
  pinMode(PIN_OFFSET_EN, OUTPUT);
  digitalWrite(PIN_OFFSET_EN, HIGH);
  
  SPI.begin();
}

int resistance = 0;

void SetPotiResistance()
{  
  if (resistance == 255) {
    resistance = 0;
  } else {
    resistance += 1;
  }
  
  Serial.print("Setting gain poti to ");
  Serial.print(resistance);
  
  digitalWrite(PIN_GAIN_EN, LOW);
  delay(100);
  
  int retval = SPI.transfer(resistance);
  delay(100);
  
  digitalWrite(PIN_GAIN_EN, HIGH);
  
  Serial.print(" ... done (");
  Serial.print(retval);
  Serial.println(").");

  delay(1000);
}

void setup()
{
  Serial.begin(115200);
  StartSPI();
}

void loop()
{
  SetPotiResistance();
}