#include "TeensyTimerTool.h"
using namespace TeensyTimerTool;

PeriodicTimer t1(TCK);
PeriodicTimer t2(TCK);

void isr1()
{
    Serial.printf("called @: %u ms\n", millis());
}

void isr2()
{
    digitalToggleFast(LED_BUILTIN);
}

void isr3()
{
    digitalWriteFast(0,HIGH);
    delayMicroseconds(10);
    digitalWriteFast(0, LOW);
}

void setup()
{
    pinMode(LED_BUILTIN, OUTPUT);

    t1.begin(isr1, 5.02s);   // instead of 5020000 (µs)
    t2.begin(isr2, 25ms);    // instead of   25000 (µs)
    t2.begin(isr3, 100_kHz); // instead of      10 (µs)
}

void loop()
{
}