/*
*
* by Lewis Loflin www.bristolwatch.com lewis@bvu.net
* http://www.bristolwatch.com/rpi/pcf8591Rpi.htm
* PCF8591Test2.c
* Using wiringPi by Gordon Henderson
* This must be installed first.
*
* Here connect the DAC output to AN0 and a potentiometer to AN1
* Read pot on AN1, write value to DAC, Read DAC with AN0
* DAC output value only good to ~200
*
* There is no warrenty of any kind use at your own risk.
*
*/

#include <wiringPiI2C.h>
#include <wiringPi.h>
#include <stdlib.h>
#include <stdio.h>

const char PCF8591 = 0x48; // base address

int fd, adcVal;

int main()   {

  if (wiringPiSetup () == -1) exit (1);

  fd = wiringPiI2CSetup(PCF8591);

  while (1)   {
    // read ADC1
    wiringPiI2CReadReg8(fd, PCF8591 + 1) ; // dummy read
    adcVal = wiringPiI2CReadReg8(fd, PCF8591 + 1) ;
    printf("Pot value = %d ", adcVal);

    // write to DAC reg, 0x04
    wiringPiI2CWriteReg8 (fd, PCF8591 + 4, adcVal) ;

    // read back DAC value with AN0
    wiringPiI2CReadReg8(fd, PCF8591) ; // dummy read
    adcVal = wiringPiI2CReadReg8(fd, PCF8591);
    printf("DAC value = %d \n\n" , adcVal);

    delay(500);

  }

  return 0;

}