I am trying to adapt the following code for Mega, as it was originally written for, and works well with, Uno: it interfaces with a KY-040 rotary encoder to simply increments/decrement a counter based on a clockwise/counterclockwise rotation of the rotary encoder.
/*******Interrupt-based Rotary Encoder Sketch*******
by Simon Merrett, based on insight from Oleg Mazurov, Nick Gammon, rt, Steve Spence
modified at EE to include the select switch
Tutorial at:
http://exploreembedded.com/wiki/Interactive_Menus_for_your_project_with_a_Display_and_an_Encoder
*/
static int pinA = 2; // Our first hardware interrupt pin is digital pin 2
static int pinB = 3; // Our second hardware interrupt pin is digital pin 3
static int selectSwitch = 9; //The select switch for our encoder.
volatile byte aFlag = 0; // let's us know when we're expecting a rising edge on pinA to signal that the encoder has arrived at a detent
volatile byte bFlag = 0; // let's us know when we're expecting a rising edge on pinB to signal that the encoder has arrived at a detent (opposite direction to when aFlag is set)
volatile uint16_t encoderPos = 0; //this variable stores our current value of encoder position. Change to int or uin16_t instead of byte if you want to record a larger range than 0-255
volatile uint16_t oldEncPos = 0; //stores the last encoder position value so we can compare to the current reading and see if it has changed (so we know when to print to the serial monitor)
volatile byte reading = 0; //somewhere to store the direct values we read from our interrupt pins before checking to see if we have moved a whole detent
void setup() {
pinMode(pinA, INPUT_PULLUP); // set pinA as an input, pulled HIGH to the logic voltage (5V or 3.3V for most cases)
pinMode(pinB, INPUT_PULLUP); // set pinB as an input, pulled HIGH to the logic voltage (5V or 3.3V for most cases)
pinMode(selectSwitch, INPUT_PULLUP);
attachInterrupt(0,PinA,RISING); // set an interrupt on PinA, looking for a rising edge signal and executing the "PinA" Interrupt Service Routine (below)
attachInterrupt(1,PinB,RISING); // set an interrupt on PinB, looking for a rising edge signal and executing the "PinB" Interrupt Service Routine (below)
Serial.begin(115200); // start the serial monitor link
}
void PinA(){
cli(); //stop interrupts happening before we read pin values
reading = PIND & 0xC; // read all eight pin values then strip away all but pinA and pinB's values
if(reading == B00001100 && aFlag) { //check that we have both pins at detent (HIGH) and that we are expecting detent on this pin's rising edge
encoderPos --; //decrement the encoder's position count
bFlag = 0; //reset flags for the next turn
aFlag = 0; //reset flags for the next turn
}
else if (reading == B00000100) bFlag = 1; //signal that we're expecting pinB to signal the transition to detent from free rotation
sei(); //restart interrupts
}
void PinB(){
cli(); //stop interrupts happening before we read pin values
reading = PIND & 0xC; //read all eight pin values then strip away all but pinA and pinB's values
if (reading == B00001100 && bFlag) { //check that we have both pins at detent (HIGH) and that we are expecting detent on this pin's rising edge
encoderPos ++; //increment the encoder's position count
bFlag = 0; //reset flags for the next turn
aFlag = 0; //reset flags for the next turn
}
else if (reading == B00001000) aFlag = 1; //signal that we're expecting pinA to signal the transition to detent from free rotation
sei(); //restart interrupts
}
void loop(){
if(oldEncPos != encoderPos) {
Serial.println(encoderPos);
oldEncPos = encoderPos;
}
// The select switch is pulled high, hence the pin goes low if the switch is pressed.
if(digitalRead(selectSwitch)==0)
{
Serial.println("Key Pressed");
delay(5); // wait for debounce to get over
}
}
After countless research, I read that the pinout for hardware interrupts, which this code absolutely requires, for Mega is different from Uno. So, if we are to use pins 2 and 3 as this code suggests on the Mega, we have to change this line
attachInterrupt(0,PinA,RISING); // set an interrupt on PinA, looking for a rising edge signal and executing the "PinA" Interrupt Service Routine (below)
attachInterrupt(1,PinB,RISING); // set an interrupt on PinB, looking for a rising edge signal and executing the "PinB" Interrupt Service Routine (below)
to this
attachInterrupt(4,PinA,RISING); // set an interrupt on PinA, looking for a rising edge signal and executing the "PinA" Interrupt Service Routine (below)
attachInterrupt(5,PinB,RISING); // set an interrupt on PinB, looking for a rising edge signal and executing the "PinB" Interrupt Service Routine (below)
Which I did, and still, the only thing that works is the rotary encoder's button -- the Mega absolutely does not register any rotating of the encoder (no LED on TX is observed).
Since I am new to Arduino, something tells me I am missing some concepts here, particularly where those if/else statements relate to those Hexs and binaries (see void functions PinA and PinB)...
Can someone please help point me in the right direction?