Arduino debugging - external timer clock

nasty_timer_debugger.ino

// This creates an external pulse source for an Arduino board - useful for timer debugging!

/* python

from time import sleep
from serial import Serial
from ctypes import c_uint32
from avrpy.mega328P import Mega328P

avr = Mega328P("COM6")


def cu32(value):
    assert value < 2**32, "value exceeds 32 bit"
    return c_uint32(value)


c = Serial("COM8", baudrate=2000000)


def q():
    avr.com.write(b"?xxxx")
    sleep(0.02)
    print(avr.com.read_all().decode())


def p(N):
    c.write(cu32(N))
    sleep(1.4e-6 * (N + 100))
    q()


*/

#include <stdint.h>

void setup_IO_ports()
{
DDRC = 0xff;
DDRB = 0xFF;
}

void setup_UART()
{
    Serial.begin(2000000);
    Serial.setTimeout(10); // ms

    // Wait until the serial port is ready
    while (!Serial)
    {
    }
    Serial.flush();
}

void setup()
{
  setup_IO_ports();
  setup_UART();
}

void loop() {
    uint32_t N;
    if (Serial.available())
    {
        if (Serial.readBytes((char *) &N, 4) == 4)
        {
            Serial.println(N);
            for (uint32_t i = 0; i < N; i++){
              PORTC = 0xFF;
              PORTC = 0;
            }
        }
    }

}


/// On the other board run something like this:
/*
    // Stop image acquisition
    case '?':
        Serial.print("ICR1=");
        Serial.println(ICR1);
        Serial.print("OCR1A=");
        Serial.println(OCR1A);
        Serial.print("OCR1B=");
        Serial.println(OCR1B);
        Serial.print("TCNT1=");
        Serial.println(TCNT1);
        Serial.print("sys.time=");
        Serial.println((uint32_t)sys.time);
        Serial.println("");
        break;
*/