A class member function calling from other class member function (arduino) - function

Question

I am developing nema stepper motor driver interfacing with arduino. I created a class. I named it Axis. I want to create an axis object for each motor with this class. but, I can not call the attachInterrupt function in the arduino.h from the class. It return this error :
In member function 'void Axis::setReverseInt()':
parsstep.cpp:12:77: error: invalid use of non-static member function 'void Axis::revDirection()'
attachInterrupt(digitalPinToInterrupt(reverseDirPin), revDirection, RISING);
Axis::Axis()
{
}
Axis::~Axis()
{
}
void Axis::setReverseInt () {
attachInterrupt(digitalPinToInterrupt(reverseDirPin), revDirection, RISING);
}
void Axis::setStopInt () {
//attachInterrupt(digitalPinToInterrupt(stopPin), stopMotor, RISING);
}
void Axis::revDirection()
{
dirMode = !dirMode;
}
void Axis::stopMotor()
{
moveMotor = !moveMotor;
}
void Axis::startMotor()
{
moveMotor = true;
}
void Axis::moveStep(int pulseRev, byte laps, boolean dir)
{
digitalWrite(dirPin, dir);
int totalPulse = pulseRev * laps;
for (int i = 0; i < totalPulse; i++)
{
speedValue = map((analogRead(speedPin)), 0, 1023, 2000, 10);
digitalWrite(pulsePin, HIGH);
delayMicroseconds(speedValue);
digitalWrite(pulsePin, LOW);
delayMicroseconds(speedValue);
}
}

Answer 1

I faced a similar issue when writing my own libraries for a big project I've been working on. It happened to me while configuring interrupts inside a method. I found a workaround that while it might seem a bit more complex, it does the trick. In my case, I used it for reading a rotary encoder its switch.
What I used is a pointer to an ISR handler and a method to call it. On your setup function you can call the initialization of the ISR service.
First, in your .h file declare the following methods (in addition to your own):
void init();
static void ISRHandler();
void setupISRHandler(uint8_t pin, void (*ISR)(void), int state); // this will configure your ISR
and a pointer:
static Axis *_ISRPointer; // can be declared as private (like in here from the '_' prefix)
Then, in your .cpp file you use it like this:
#include "Axis.h"
Axis *Axis::_ISRPointer = nullptr;
you will initialize the ISR handler during the setup using the init method:
void Axis::init(){
setupISRHandler(reverseDirPin, Axis::ISRHandler, RISING);
}
the setup method looks like:
void Axis::setupISRHandler(uint8_t pin, void (*ISRFunction)(void), int state){
attachInterrupt(digitalPinToInterrupt(pin), ISRFunction, state);
}
the ISRHandler is in charge of calling the ISR routine:
void Axis::ISRHandler(){
_ISRPointer-> revDirection();
}
void Axis::revDirection(void){
// Do not forget to disable interrupts
cli();
// your routine goes here
dirMode= !dirMode;
sei();
}
Therefore, you will do something like this in your main .ino file:
#include "Axis.h"
#include <whateverotherlibraryyouneed.h>
Axis ax = Axis(); // your new object
void setup(){
ax.init();
ax.startMotor();
}
void loop(){
if(day == SUNNY){
ax.moveStep(100, 2 , CLOCKWISE);
} else {
ax.stopMotor();
}
ax.someOtherMethodToControlTheMotor(anyArgumentYouWant);
}
I hope that my convoluted solution helps
Cheers
Dr. Daniel