pwm.ceu

#ifndef PWM_CEU
#define PWM_CEU

// TODO: timers vs wclock and other drivers

#if 0
https://forum.arduino.cc/index.php?topic=410287.0
On a UNO as we only have 3 timers but 6 PWM pins, they go in pairs and the relation between timers and PWM outputs is as follow:

- timer0 = Pins 5, 6
- timer1 = Pins 9, 10
- timer2 = Pins 11, 3

On a MEGA you have 6 timers but 15 PWM pins (PWM: 2 to 13 and 44 to 46) , they also go in pair or triples

- timer0 = Pins 4, 13
- timer1 = Pins 11,12
- timer2 = Pins 9, 10
- timer3 = Pin 2, 3, 5
- timer4 = Pin 6, 7, 8
- timer5 = Pin 44, 45, 46
#endif

native/pos do
    static int pwm_refs = 0;
    void pwm_inc (int v) {
        pwm_refs += v;
        if (pwm_refs == 0) {
            ceu_pm_set(CEU_PM_TIMER0, 0);
            ceu_pm_set(CEU_PM_TIMER1, 0);
            ceu_pm_set(CEU_PM_TIMER2, 0);
#ifdef ARDUINO_BOARD_MEGA
            ceu_pm_set(CEU_PM_TIMER3, 0);
            ceu_pm_set(CEU_PM_TIMER4, 0);
            ceu_pm_set(CEU_PM_TIMER5, 0);
#endif
        } else if (pwm_refs == 1) {
            ceu_pm_set(CEU_PM_TIMER0, 1);
            ceu_pm_set(CEU_PM_TIMER1, 1);
            ceu_pm_set(CEU_PM_TIMER2, 1);
#ifdef ARDUINO_BOARD_MEGA
            ceu_pm_set(CEU_PM_TIMER3, 1);
            ceu_pm_set(CEU_PM_TIMER4, 1);
            ceu_pm_set(CEU_PM_TIMER5, 1);
#endif
        }
    }
end

output (int pin, u8 v) PWM do
    _analogWrite(pin, v);
end

code/await Pwm (var int pin, var u8 v) -> NEVER do
    { pwm_inc(1); }
    do finalize with
        { pwm_inc(-1); }
    end

    emit PWM(pin, v);
    await FOREVER;
end

#endif