void Arduino::frequencyTest1()
{
    ::pinMode(GPIO5, DIRECTION_OUT);
    ::pinMode(GPIO6, DIRECTION_OUT);
    ::digitalWrite(GPIO5, LOW);
    ::digitalWrite(GPIO6, LOW);

    while (true) {
        unsigned long m = millis();
        ::digitalWrite(GPIO5, HIGH);
        ::delay(10);

        while (millis() - m < 10000) {
            ::digitalWrite(GPIO6, HIGH);
            ::delayMicroseconds(50);
            ::digitalWrite(GPIO6, LOW);
        }

        ::delay(10);
        ::digitalWrite(GPIO5, LOW);

        ::delay(500);
    }
}