File content as of revision 0:252d645cfc5d:

/* Asynchronous Stepper with 4-pin output
 *
 * Written by Simon Krogedal
 * 31/05/2021
 * Team 9 4th Year project
 * 
 * for NUCLEO-F401RE
 * 
 * Version 0.1
 *
 */
 
#include "Async_4pin_Stepper.h"

// Constructor takes 4 pins and a steps/rev in float presicion
Async_4pin_Stepper::Async_4pin_Stepper( PinName StepperPin1,
                                        PinName StepperPin2,
                                        PinName StepperPin3,
                                        PinName StepperPin4,
                                        float   StepsPerRev) :
                                        
                                        output(StepperPin1,
                                               StepperPin2,
                                               StepperPin3,
                                               StepperPin4)
{
    SPR = StepsPerRev;
    setSpeed(500);
    currentPos = 0;
    relax();
}

void Async_4pin_Stepper::setZeroPos() {currentPos = 0;}

void Async_4pin_Stepper::setSpeed(int speed) {
    if(speed > 0) {
        speed_ = speed;
        stepInterval = 1.0/speed;
    }
    else {
        speed_ = 0;
        stepInterval = 0;
    }
}

int Async_4pin_Stepper::getPos() {return currentPos;}
int Async_4pin_Stepper::getTarget() {return targetPos;}
int Async_4pin_Stepper::getSpeed() {return speed_;}
int Async_4pin_Stepper::distanceToGo() {return targetPos-currentPos;}

void Async_4pin_Stepper::step(int step) {
    switch (step & 0x7) {
        case 0:    // 1000
            output = 0b0001;
            break;
            
        case 1:    // 1010
            output = 0b0101;
            break;
            
        case 2:    // 0010
            output = 0b0100;
            break;
            
        case 3:    // 0110
            output = 0b0110;
            break;
            
        case 4:    // 0100
            output = 0b0010;
            break;
            
        case 5:    //0101
            output = 0b1010;
            break;
            
        case 6:    // 0001
            output = 0b1000;
            break;
            
        case 7:    //1001
            output = 0b1001;
            break;
    }
}

void Async_4pin_Stepper::stepOnceCCW() {
    // Update current position
    currentPos++;
    // Step to new position
    step(currentPos);
}

void Async_4pin_Stepper::stepOnceCW() {
    // Update current position
    currentPos--;
    // Step to new position
    step(currentPos);
}

void Async_4pin_Stepper::setTarget(int target) {targetPos = target;}

void Async_4pin_Stepper::goToTarget() {
    // Check if at target or standstill
    if(!distanceToGo() || !stepInterval || running)
        return;
    else { // Attach ticker to callback function
        ticker.attach(callback(this, &Async_4pin_Stepper::stepCB), stepInterval);
        running = true;
    }
}

void Async_4pin_Stepper::stepCB() {
    // check error value for driction
    int error = distanceToGo();
    if(error == 0) {
        ticker.detach();
        running = false;
    }
    else if(error > 0)
        stepOnceCCW();
    else
        stepOnceCW();
}        

void Async_4pin_Stepper::relax() {output = 0;}
bool Async_4pin_Stepper::isRunning() {return running;}
void Async_4pin_Stepper::stop() {ticker.detach();}