I want to send PWM signal through an analog pin on Arduino Mega 2560 but MATLAB code is too slow

Hi,

I want to make a code for controlling an stepper motor by an Arduino Mega 2560 and RAMPS 1.4 Shield, here is the mapping

I want to control the X-motor for example, but it is controlled by analog pins. I programmed this code in Arduino IDE and it run very well, controlling the velocity of the stepper motor correctly:

// defines pins numbers

const int stepPin = A0;

const int dirPin = A1;

const int enablePin= 38;

void setup() {

// Sets the two pins as Outputs

pinMode(stepPin,OUTPUT);

pinMode(dirPin,OUTPUT);

pinMode(enablePin,OUTPUT);

}

void loop() {

digitalWrite(enablePin,LOW);

digitalWrite(dirPin,HIGH);

// Makes 200 pulses for making one full cycle rotation

for(int x = 0; x < 16*200; x++) {

digitalWrite(stepPin,HIGH);

delayMicroseconds(150);

digitalWrite(stepPin,LOW);

delayMicroseconds(150);

}

digitalWrite(dirPin,LOW); //Changes the rotations direction

for(int x = 0; x < 16*200; x++) {

digitalWrite(stepPin,HIGH);

delayMicroseconds(150);

digitalWrite(stepPin,LOW);

delayMicroseconds(150);

}

}

But when i programmed this code in MATLAB, the stepper motor not run at the same velocity:

clear all;

a=arduino()

s=serial('COM7')

s.BaudRate=1000000

%A0 Step

configurePin(a,'A0','DigitalOutput');

%A1 Dir

configurePin(a,'A1','DigitalOutput');

%D38 Enable

configurePin(a,'D38','DigitalOutput');

writeDigitalPin(a, 'D38', 0);

writeDigitalPin(a, 'A0', 1);

PWM=150e-6;

for i=1:1:200*16

writeDigitalPin(a, 'A0', 1);

pause(PWM);

writeDigitalPin(a, 'A0', 0);

pause(PWM);

end

Someone knows how i could optimize the code ? or how i could use analog pins for digital outputs in functions as writePWMDutyCycle or PWM blocks in Simulink?

Answer 1

[Thomas Tramberger]

How did you solve your problem?