Dynamic short pulse generator using Arduino Mega2560 with serial control

This is a simplified version of our hybrid static/dynamic pulse generator. On the Arduino Mega2560 platform, it allows generating pulses from 750ns up to almost arbitrary lengths (limited only by the integer width) with a resolution of approx. 437.5ns

In order to control the pulse width, open a serial interface and type + to increase the pulse width or - to decrease the pulse width.

#include <Arduino.h>
#include <avr/io.h>
#include <ArduinoJson.h>

const int pulseAPin = 11;

#define PORT11 PORTB
#define PIN11 5
#define PIN11_MASK (1 << PIN11)

int pulseLength = 0;

/**
 * Pulse the output pin, for very short pulses.
 */
void PulseDynamic(int n) {
    cli();
    PORT11 |= PIN11_MASK;
    // Dynamic for loop
    for (;n >= 0; n--) {
        _NOP();
    }
    PORT11 &= ~PIN11_MASK;
    sei();
}

void setup()
{
    Serial.begin(115200);
    Serial.setTimeout(25);

    pinMode(pulseAPin, OUTPUT);
    pinMode(LED_BUILTIN, OUTPUT);
}

void loop()
{
    PulseDynamic(pulseLength);
    // Process serial
    while(Serial.available() > 0) {
        int c = Serial.read();
        if(c == '+') {
            pulseLength++;
            Serial.println(pulseLength);
        } else if(c == '-') {
            pulseLength--;
            if(pulseLength < 0) {pulseLength = 0;}
            Serial.println(pulseLength);
        }
    }
    delay(50);
}