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#include <Arduino.h>
/* interrupt routine for Rotary Encoders
tested with Noble RE0124PVB 17.7FINB-24 http://www.nobleusa.com/pdf/xre.pdf - available at pollin.de
and a few others, seems pretty universal
The average rotary encoder has three pins, seen from front: A C B
Clockwise rotation A(on)->B(on)->A(off)->B(off)
CounterCW rotation B(on)->A(on)->B(off)->A(off)
and may be a push switch with another two pins, pulled low at pin 8 in this case
raf@synapps.de 20120107
*/
// usually the rotary encoders three pins have the ground pin in the middle
enum PinAssignments {
encoderPinA = 2, // rigth
encoderPinB = 3, // left
clearButton = 8 // another two pins
};
volatile unsigned int encoderPos = 0; // a counter for the dial
unsigned int lastReportedPos = 1; // change management
static boolean rotating=false; // debounce management
// interrupt service routine vars
boolean A_set = false;
boolean B_set = false;
void setup() {
pinMode(encoderPinA, INPUT);
pinMode(encoderPinB, INPUT);
pinMode(clearButton, INPUT);
// turn on pullup resistors
digitalWrite(encoderPinA, HIGH);
digitalWrite(encoderPinB, HIGH);
digitalWrite(clearButton, HIGH);
// encoder pin on interrupt 0 (pin 2)
attachInterrupt(0, doEncoderA, CHANGE);
// encoder pin on interrupt 1 (pin 3)
attachInterrupt(1, doEncoderB, CHANGE);
Serial.begin(9600); // output
}
// main loop, work is done by interrupt service routines, this one only prints stuff
void loop() {
rotating = true; // reset the debouncer
if (lastReportedPos != encoderPos) {
Serial.print("Index:");
Serial.println(encoderPos, DEC);
lastReportedPos = encoderPos;
}
if (digitalRead(clearButton) == LOW ) {
encoderPos = 0;
}
}
// Interrupt on A changing state
void doEncoderA(){
// debounce
if ( rotating ) delay (1); // wait a little until the bouncing is done
// Test transition, did things really change?
if( digitalRead(encoderPinA) != A_set ) { // debounce once more
A_set = !A_set;
// adjust counter + if A leads B
if ( A_set && !B_set )
encoderPos += 1;
rotating = false; // no more debouncing until loop() hits again
}
}
// Interrupt on B changing state, same as A above
void doEncoderB(){
if ( rotating ) delay (1);
if( digitalRead(encoderPinB) != B_set ) {
B_set = !B_set;
// adjust counter - 1 if B leads A
if( B_set && !A_set )
encoderPos -= 1;
rotating = false;
}
}
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