Add encoder features

PCF8574.cpp

@@ -191,7 +191,7 @@ void PCF8574::begin(){
 //		attachInterrupt(digitalPinToInterrupt(_interruptPin), (*_interruptFunction), FALLING );
 		DEBUG_PRINTLN("Using interrupt pin (not all pin is interrupted)");
 		::pinMode(_interruptPin, INPUT_PULLUP);
-		attachInterrupt(digitalPinToInterrupt(_interruptPin), (*_interruptFunction), CHANGE );
+		attachInterrupt(digitalPinToInterrupt(_interruptPin), (*_interruptFunction), FALLING );
 	}
 
 	// inizialize last read
@@ -268,12 +268,111 @@ void PCF8574::pinMode(uint8_t pin, uint8_t mode, uint8_t output_start){
 	}
 };
 
+void PCF8574::encoder(uint8_t pinA, uint8_t pinB){
+	PCF8574::pinMode(pinA, INPUT_PULLUP);
+	PCF8574::pinMode(pinB, INPUT_PULLUP);
+}
+
+byte getBit(byte n, byte position)
+{
+   return (n >> position) & 1;
+}
+
+
+//int8_t PCF8574::readEncoderValue(uint8_t pinA, uint8_t pinB){
+//	  bool changed = false;
+//
+//	  byte offset = 0;
+//
+//	  byte na = PCF8574::digitalRead(pinA);
+//	  byte nb = PCF8574::digitalRead(pinB);
+//
+//	  byte encoderPinALast = (encoderValues & bit(pinA));
+//	  byte encoderPinBLast = (encoderValues & bit(pinB));
+//
+//	  if ((encoderPinALast!=na || encoderPinBLast!=nb) && (encoderPinALast == LOW) && (na == HIGH)) {
+//		if (nb == LOW) {
+//			offset = - 1;
+//			changed = true;
+//		} else {
+//			offset = + 1;
+//			changed = true;
+//		}
+//	  }
+//
+//	  encoderValues = (encoderPinALast!=na)?encoderValues ^ bit(pinA):encoderValues;
+//	  encoderValues = (encoderPinBLast!=nb)?encoderValues ^ bit(pinB):encoderValues;
+//
+//	  return offset;
+//}
+
+bool PCF8574::checkProgression(byte oldValA, byte oldValB, byte newValA, byte newValB, byte validProgression){
+	bool findOldVal = false;
+	int posFinded = 0;
+	for (int pos = 0; pos<8; pos = pos + 2){
+		if ((oldValB == ((validProgression & bit(pos+1))>0?HIGH:LOW)) && (oldValA == ((validProgression & bit(pos+0))>0?HIGH:LOW)) ){
+			findOldVal = true;
+			posFinded = pos;
+		}
+	}
+	if (!findOldVal) return false;
+
+	posFinded = posFinded + 2;
+	if (posFinded>8) posFinded = 0;
+
+	return ((newValB == ((validProgression & bit(posFinded+1))>0?HIGH:LOW)) && (newValA == ((validProgression & bit(posFinded+0))>0?HIGH:LOW)) );
+}
+
+bool PCF8574::readEncoderValue(uint8_t pinA, uint8_t pinB, volatile long *encoderValue){
+	  bool changed = false;
+
+	  byte na = PCF8574::digitalRead(pinA, true);
+	  byte nb = PCF8574::digitalRead(pinB, true);
+
+	  byte encoderPinALast = (encoderValues & bit(pinA))>0?HIGH:LOW;
+	  byte encoderPinBLast = (encoderValues & bit(pinB))>0?HIGH:LOW;
+
+	  if ((encoderPinALast!=na || encoderPinBLast!=nb) && (encoderPinALast == LOW) && (na == HIGH)) {
+		  bool vCW = checkProgression(encoderPinALast, encoderPinBLast, na, nb, validCW);
+		  bool vCCW = checkProgression(encoderPinALast, encoderPinBLast, na, nb, validCCW);
+
+			if (nb == LOW) {
+	//			checkCW(encoderPinALast, encoderPinBLast, na, nb);
+				*encoderValue = *encoderValue - 1;
+				changed = true;
+			} else {
+				*encoderValue = *encoderValue + 1;
+				changed = true;
+			}
+//			if (nb == LOW && vCW) {
+//	//			checkCW(encoderPinALast, encoderPinBLast, na, nb);
+//				*encoderValue = *encoderValue - 1;
+//				changed = true;
+//			} else if (vCCW) {
+//				*encoderValue = *encoderValue + 1;
+//				changed = true;
+//			}
+
+	  }
+
+		encoderValues = (encoderPinALast!=na)?encoderValues ^ bit(pinA):encoderValues;
+		encoderValues = (encoderPinBLast!=nb)?encoderValues ^ bit(pinB):encoderValues;
+
+		return changed;
+}
+
+int8_t PCF8574::readEncoderValue(uint8_t pinA, uint8_t pinB) {
+	volatile long encoderValue = 0;
+	PCF8574::readEncoderValue(pinA, pinB, &encoderValue);
+	return encoderValue;
+}
+
 /**
  * Read value from i2c and bufferize it
  * @param force
  */
 void PCF8574::readBuffer(bool force){
-	if (millis() > PCF8574::lastReadMillis+READ_ELAPSED_TIME || _usingInterrupt || force){
+	if (millis() > PCF8574::lastReadMillis+latency || _usingInterrupt || force){
 		_wire->requestFrom(_address,(uint8_t)1);// Begin transmission to PCF8574 with the buttons
 		lastReadMillis = millis();
 		if(_wire->available())   // If bytes are available to be recieved
@@ -371,7 +470,7 @@ void PCF8574::readBuffer(bool force){
  * @param pin
  * @return
  */
-uint8_t PCF8574::digitalRead(uint8_t pin){
+uint8_t PCF8574::digitalRead(uint8_t pin, bool forceReadNow){
 	uint8_t value = (bit(pin) & readModePullUp)?HIGH:LOW;
 	DEBUG_PRINT("Read pin ");
 	DEBUG_PRINT (pin);
@@ -392,7 +491,7 @@ uint8_t PCF8574::digitalRead(uint8_t pin){
 		  }else{
 			  value = LOW;
 		  }
-	 }else if ((/*(bit(pin) & byteBuffered)<=0 && */millis() > PCF8574::lastReadMillis+READ_ELAPSED_TIME) /*|| _usingInterrupt*/){
+	 }else if (forceReadNow || (millis() > PCF8574::lastReadMillis+latency)){
 		 DEBUG_PRINT(" ...Read from buffer... ");
 		  _wire->requestFrom(_address,(uint8_t)1);// Begin transmission to PCF8574 with the buttons
 		  lastReadMillis = millis();

PCF8574.h

@@ -61,7 +61,7 @@
 #endif
 
 #ifdef PCF8574_LOW_LATENCY
-	#define READ_ELAPSED_TIME 1
+	#define READ_ELAPSED_TIME 0
 #else
 	#define READ_ELAPSED_TIME 10
 #endif
@@ -110,8 +110,10 @@ public:
 	void begin();
 	void pinMode(uint8_t pin, uint8_t mode, uint8_t output_start = HIGH);
 
+	void encoder(uint8_t pinA, uint8_t pinB);
+
 	void readBuffer(bool force = true);
-	uint8_t digitalRead(uint8_t pin);
+	uint8_t digitalRead(uint8_t pin, bool forceReadNow = false);
 	#ifndef PCF8574_LOW_MEMORY
 		struct DigitalInput {
 			uint8_t p0;
@@ -131,6 +133,17 @@ public:
 	#endif
 	void digitalWrite(uint8_t pin, uint8_t value);
 
+	bool readEncoderValue(uint8_t pinA, uint8_t pinB, volatile long *encoderValue);
+	int8_t readEncoderValue(uint8_t pinA, uint8_t pinB);
+
+	int getLatency() const {
+		return latency;
+	}
+
+	void setLatency(int latency = READ_ELAPSED_TIME) {
+		this->latency = latency;
+	}
+
 private:
 	uint8_t _address;
 
@@ -163,6 +176,19 @@ private:
 
 	byte writeByteBuffered = B00000000;
 
+	byte encoderValues = B00000000;
+
+	uint8_t prevNextCode = 0;
+	uint16_t store=0;
+
+	int latency = READ_ELAPSED_TIME;
+
+	bool checkProgression(byte oldValA, byte newValA, byte oldValB, byte newValB, byte validProgression);
+
+//	byte validCW = B11100001;
+//	byte validCCW = B01001011;
+	byte validCW = B01001011;
+	byte validCCW = B11100001;
 };
 
 #endif

examples/Arduino4Leds4ButtonsWithInterrupt/Arduino4Leds4ButtonsWithInterrupt.ino

@@ -0,0 +1,80 @@
+/*
+ KeyPressed and leds with interrupt
+ by Mischianti Renzo <http://www.mischianti.org>
+
+ https://www.mischianti.org/2019/01/02/pcf8574-i2c-digital-i-o-expander-fast-easy-usage/
+*/
+
+#include "Arduino.h"
+#include "PCF8574.h"
+
+// For arduino uno only pin 1 and 2 are interrupted
+#define ARDUINO_UNO_INTERRUPTED_PIN 2
+
+// Function interrupt
+void keyPressedOnPCF8574();
+
+// Set i2c address
+PCF8574 pcf8574(0x38, ARDUINO_UNO_INTERRUPTED_PIN, keyPressedOnPCF8574);
+unsigned long timeElapsed;
+void setup()
+{
+	Serial.begin(115200);
+
+	pcf8574.pinMode(P0, INPUT_PULLUP);
+	pcf8574.pinMode(P1, INPUT_PULLUP);
+	pcf8574.pinMode(P2, INPUT);
+	pcf8574.pinMode(P3, INPUT);
+
+	pcf8574.pinMode(P7, OUTPUT);
+	pcf8574.pinMode(P6, OUTPUT, HIGH);
+	pcf8574.pinMode(P5, OUTPUT);
+	pcf8574.pinMode(P4, OUTPUT, LOW);
+
+	pcf8574.begin();
+
+	timeElapsed = millis();
+}
+unsigned long lastSendTime = 0;        // last send time
+unsigned long interval = 4000;          // interval between sends
+
+bool startVal = HIGH;
+
+bool keyPressed = false;
+void loop()
+{
+	if (keyPressed){
+		uint8_t val0 = pcf8574.digitalRead(P0);
+		uint8_t val1 = pcf8574.digitalRead(P1);
+		uint8_t val2 = pcf8574.digitalRead(P2);
+		uint8_t val3 = pcf8574.digitalRead(P3);
+		Serial.print("P0 ");
+		Serial.print(val0);
+		Serial.print(" P1 ");
+		Serial.print(val1);
+		Serial.print(" P2 ");
+		Serial.print(val2);
+		Serial.print(" P3 ");
+		Serial.println(val3);
+		keyPressed= false;
+	}
+
+	  if (millis() - lastSendTime > interval) {
+			pcf8574.digitalWrite(P7, startVal);
+			if (startVal==HIGH) {
+				startVal = LOW;
+			}else{
+				startVal = HIGH;
+			}
+			lastSendTime = millis();
+
+			Serial.print("P7 ");
+			Serial.println(startVal);
+	  }
+}
+
+void keyPressedOnPCF8574(){
+	// Interrupt called (No Serial no read no wire in this function, and DEBUG disabled on PCF library)
+	 keyPressed = true;
+
+}

examples/encoderWithBasicLibraryFunction/encoderWithBasicLibraryFunction.ino

@@ -0,0 +1,91 @@
+/*
+ * PCF8574 GPIO Port Expand
+ * https://www.mischianti.org
+ *
+ * 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.pinMode(encoderPinA, INPUT_PULLUP);
+	  pcf8574.pinMode(encoderPinB, INPUT_PULLUP);
+	  // encoder button
+	  pcf8574.pinMode(P2, INPUT_PULLUP);
+
+	  // Set low latency with this method or uncomment LOW_LATENCY define in the library
+	  // Needed for encoder
+	  pcf8574.setLatency(0);
+
+	  // Start library
+	  pcf8574.begin();
+}
+
+bool changed = false;
+
+void loop()
+{
+	if (changed){
+		Serial.print("ENCODER --> ");
+		Serial.print(encoderValue);
+		Serial.print(" - BUTTON --> ");
+		Serial.println(encoderButtonVal?"HIGH":"LOW");
+		changed = false;
+	}
+}
+
+uint8_t encoderPinALast = LOW;
+uint8_t valPrecEncoderButton = LOW;
+
+void updateEncoder(){
+	// Encoder management
+	uint8_t n = pcf8574.digitalRead(encoderPinA);
+	if ((encoderPinALast == LOW) && (n == HIGH)) {
+		if (pcf8574.digitalRead(encoderPinB) == LOW) {
+			encoderValue--;
+			changed = true; // Chnged the value
+		} else {
+			encoderValue++;
+			changed = true; // Chnged the value
+		}
+	}
+	encoderPinALast = n;
+
+	// Button management
+	encoderButtonVal = pcf8574.digitalRead(P2);
+	if (encoderButtonVal!=valPrecEncoderButton){
+	  changed = true; // Chnged the value of button
+	  valPrecEncoderButton = encoderButtonVal;
+	}
+}