ESPIoTBase/lib/PCF8574_library-2.3.4/examples/encoderWithFullLibraryFunction/encoderWithFullLibraryFunction.ino

/*
 * PCF8574 GPIO Port Expand
 * https://www.mischianti.org/2020/03/13/pcf8574-i2c-digital-i-o-expander-rotary-encoder-part-2/
 *
 * PCF8574    ----- WeMos
 * A0         ----- GRD
 * A1         ----- GRD
 * A2         ----- GRD
 * VSS        ----- GRD
 * VDD        ----- 5V/3.3V
 * SDA        ----- D1(PullUp)
 * SCL        ----- D2(PullUp)
 * INT        ----- INT(PullUp)
 *
 * P0     ----------------- ENCODER PIN A
 * P1     ----------------- ENCODER PIN B
 * P2     ----------------- ENCODER BUTTON
 *
 */
#include "Arduino.h"
#include "PCF8574.h"

int encoderPinA = P0;
int encoderPinB = P1;

#define INTERRUPTED_PIN D7

void ICACHE_RAM_ATTR updateEncoder();

// initialize library
PCF8574 pcf8574(0x38, INTERRUPTED_PIN, updateEncoder);

volatile long encoderValue = 0;
uint8_t encoderButtonVal = HIGH;

void setup()
{
	Serial.begin (9600);
	delay(500);

	// encoder pins
	pcf8574.encoder(encoderPinA, encoderPinB);
	// encoder button
	pcf8574.pinMode(P2, INPUT);

	// Start library
	Serial.print("Init pcf8574...");
	if (pcf8574.begin()){
		Serial.println("OK");
	}else{
		Serial.println("KO");
	}

}

bool changed = false;

// The loop function is called in an endless loop
void loop()
{
	if (changed){
		Serial.print("ENCODER --> ");
		Serial.print(encoderValue);
		Serial.print(" - BUTTON --> ");
		Serial.println(encoderButtonVal?"HIGH":"LOW");
		changed = false;
	}
}

bool valPrecEncoderButton = LOW;
void updateEncoder(){
	changed = pcf8574.readEncoderValue(encoderPinA, encoderPinB, &encoderValue);

//	int vale = pcf8574.readEncoderValue(encoderPinA, encoderPinB);
//	if (vale!=0){
//		changed = true;
//	}
//	encoderValue = encoderValue + vale;

	// Button management
	encoderButtonVal = pcf8574.digitalRead(P2);
	if (encoderButtonVal!=valPrecEncoderButton){
	  changed = true; // Chnged the value of button
	  valPrecEncoderButton = encoderButtonVal;
	}
}