Direct port access in Arduino IDE

[Stefan_69]

Hello s.micic,

sorry for the late response, was quite busy at work … Anyhow, I’ll paste my code below, as mentioned in the original post I want to modify the duty cylce of an incoming PWM signal while keeping its frequency constant. You will find both methods (“Arduino style” and “fast style”) for setting the GPIO pin.

If you are using the Arduino IDE you can also have a look at “wiring_digital.c” which can be found under “AppData\Local\Arduino15\packages\Seeeduino\hardware\samd\1.7.9\cores\arduino”

Hope this helps,
Stefan

@""

const byte inPin = 1;
const byte interruptPin = 1;
const byte outPin = 3;
const byte testPin = 5;
uint32_t ulPin = 5;
uint32_t myPin = 1 ;

volatile byte state = LOW;
volatile byte myvar;
//
volatile EPortType port = g_APinDescription[ulPin].ulPort;
volatile uint32_t pin = g_APinDescription[ulPin].ulPin;
volatile uint32_t pinMask = (1ul << pin);

void setup() {
pinMode(inPin, INPUT);
pinMode(outPin, OUTPUT);
pinMode(testPin, OUTPUT);
pinMode(interruptPin, INPUT_PULLUP);
attachInterrupt(digitalPinToInterrupt(interruptPin), blink, CHANGE);
}

void loop() {
}

void blink() {
PORT->Group[port].OUTCLR.reg = pinMask;
if (digitalRead(inPin) == 0) {
// PORT->Group[port].OUTCLR.reg = pinMask; //LOW
digitalWrite(outPin,LOW);
}
else {
delayMicroseconds(10); // modify duty cycle
// PORT->Group[port].OUTSET.reg = pinMask; //HIGH
digitalWrite(outPin,HIGH);
}
}