Arduino Nano R4 support

[HubertJH]

Unfortunately, the library (1.4.4) installed from within the Arduino IDE does not support the Nano R4 (and most likely also the other R4 boards) as the interrupt pins are not defined for those boards. Compiling example Basic.ino fails.

Replacing ...libraries/Encoder/utilities with the folder posted here on GitHub fixes that issue as indeed the interrupt definitions were added.

However, compiling for the standard Nano (as well as Uno) now fails throwing a lengthy error message starting with

...Arduino/libraries/Encoder/Encoder.h:68:11: error: 'IO_REG_TYPE' does not name a type
volatile IO_REG_TYPE * pin1_register;
...
and further down pointing to errors in direct_pin_read.h

...utility/direct_pin_read.h:8:46: note: in definition of macro 'DIRECT_PIN_READ'
#define DIRECT_PIN_READ(base, mask) (((*(base)) & (mask)) ? 1 : 0)
...

Also replacing Encoder.h with the post on GitHub does not help (although the files are different) i.e. R4 compiles fine, standard fails.

While you can work around this issue it would be great if this could be fixed at some point.

[dawinaj]

EDIT 3: SOLVED

Original:
Even with the latest code from this repo, the library does not work on Nano R4.

The basic example fails:

#include <Encoder.h>
Encoder myEnc;

void setup() {
 Serial.begin(115200);
 Serial.println("Basic Encoder Test:");
 myEnc.begin(2, 3);
}

long oldPosition = -999;

void loop() {
 long newPosition = myEnc.read();
 if (newPosition != oldPosition) {
 oldPosition = newPosition;
 Serial.println(newPosition);
 }
}

Prints numbers around zero, like

0
1
0
1
0
1
0
1
0
1

While a really basic AI slop works as supposed:

volatile long pos = 0;

void isrA() {
 bool A = digitalRead(2);
 bool B = digitalRead(3);
 pos += (A == B) ? 1 : -1;
}

void isrB() {
 bool A = digitalRead(2);
 bool B = digitalRead(3);
 pos += (A != B) ? 1 : -1;
}

void setup() {
 pinMode(2, INPUT_PULLUP);
 pinMode(3, INPUT_PULLUP);

 attachInterrupt(digitalPinToInterrupt(2), isrA, CHANGE);
 attachInterrupt(digitalPinToInterrupt(3), isrB, CHANGE);

 Serial.begin(115200);
}

void loop() {
 Serial.println(pos);
}

Edit 1:
What I found after adding some prints, is that when turning the encoder in one direction (almost) only the pin2 isr fires, while turning the other direction (almost) only the pin3 isr fires.
I have no idea how this is possible.

Edit 2: Turns out I should have used 5V instead of 3.3V for the encoder... Nevertheless that's a really weird symptom.