PCF8591/PCF8591.cpp at master · Vampir8/PCF8591 · GitHub

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//
// PCF8591
//

#include <Wire.h>
#ifdef __AVR__
#include <avr/pgmspace.h>
#endif
#include "PCF8591.h"

#if ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif

// ctor
PCF8591::PCF8591 ()
{
}

// begin
void PCF8591::begin (uint8_t addr)
{
	// i2cAddr cannot be higher than 7
	if (addr > 7)
		addr = 7;


	_i2cAddr = PCF8591_ADDRESS | addr;

	// initialize i2c library
	Wire.begin ();
}

uint8_t PCF8591::analogRead (const uint8_t pin)
{
	// there are only 4 pins. so value cannot be more than 3
	if (pin > 3)
		return 0;

	Wire.beginTransmission(_i2cAddr);

	Wire.write (pin);

	Wire.endTransmission ();

	Wire.requestFrom (_i2cAddr, 2);

	// read and discard first byte
	Wire.read ();

	// return 2nd byte
	return Wire.read ();
}

void PCF8591::analogWrite (const uint8_t val)
{

	Wire.beginTransmission(_i2cAddr);

	Wire.write (0x40);

	Wire.write (val);

	Wire.endTransmission ();

}