/*
 *
 * RP2040_interrupt_simple-2.ino
 *
 * code from:
 *
 * https://wokwi.com/projects/381398511352819713
 * author: Alan Reed, 2021
 * 
 * https://raspberrypi.stackexchange.com/questions/137456/rpi-pico-irq-with-callback-freezes-pico
 * author: tmajz @ May 12, 2022
 *
 *
 * code developed on: WOKWI
 * https://wokwi.com/projects/391893524910605313
 *  
 *
 * // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
 * //
 * // only ONE CALLBACK can be implemented for -ALL- the interrupts
 * //
 * // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
 *
 *
 * -----------------------------------------------------------------------------------------------------------------------
 *
 *
 * https://arduino-pico.readthedocs.io/en/latest/analog.html
 *
 * Analog Outputs
 * The RP2040 does not have any onboard DACs, so analog outputs are simulated
 * using the standard method of using pulse width modulation (PWM) using
 * the RP2040’s hardware PWM units.
 * While up to 16 PWM channels can be generated, they are not independent
 * and there are significant restrictions as to allowed pins in parallel.
 * See the RP2040 datasheet for full details.
 *
 * Analog Output Restrictions
 * The PWM generator source clock restricts the legal combinations
 * of frequency and ranges. At a CPU frequency of 133MHz, the 16 bit
 * maximum range decreases by 1 bit for every doubling of the default
 * PWM frequency of 1 kHz. For example, at 1MHz only about 6 bits
 * of range are possible. When you define an analogWriteFreq and
 * analogWriteRange that can’t be fulfilled by the hardware, the frequency
 * will be preserved but the accuracy (range) will be reduced automatically.
 * Your code will still send in the range you specify, but the core itself
 * will transparently map it into the allowable PWN range.
 *
 * void analogWriteFreq(uint32_t freq)
 * Sets the master PWM frequency used (i.e. how often the PWM output cycles).
 * From 100Hz to 1MHz are supported.
 *
 * void analogWriteRange(uint32_t range) and analogWriteResolution(int res)
 * These calls set the maximum PWM value (i.e. writing this value will result
 * in a PWM duty cycle of 100%)/ either explicitly (range) or as a power-of-two
 * (res). A range of 16 to 65535 is supported.
 *
 * void analogWrite(pin_size_t pin, int val)
 * Writes a PWM value to a specific pin. The PWM machine is enabled and set
 * to the requested frequency and scale, and the output is generated.
 * This will continue until a digitalWrite or other digital output is performed.
 *
 *
 * -----------------------------------------------------------------------------------------------------------------------
 *
 *
 * Only on WOKWI, PAY ATTENTION to the following CONDITION:
 * using the LEFT/RIGHT mouse button, select the -PUSH BUTTON-
 * in the diagram: then proceed to UNSELECT the [Bounce] box.
 * This enables the DEBOUNCE for the selected -PUSH BUTTON-. 
 * Only on WOKWI, if you don't, ALL this code becomes GARBAGE!!
 * 
 * WARNING: to run the << decrement >> interrupt alone,
 *          the value of the GLOBAL -- Gvlt_Event8 --
 *          >>>>  MUST BE set to 255  <<<<, NOT ZERO!
 * 
 * 
*/

// ** GLOBALS declarations **************************************************
volatile uint8_t Gvlt_Event8 = 0;
//volatile uint8_t Gvlt_Event8 = 255; // USE for test DECREMENT button alone
const int G_pinINCRbttn8 = 8;
const int G_pinDECRbttn8 = 9;


// **************************************************************************
// ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
// ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
//
// only ONE CALLBACK can be implemented for -ALL- the interrupts
//
// ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
// ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
// **************************************************************************


void Bttn_clbk(uint gpio, uint32_t events) {
  //
  // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
  //
  // only ONE CALLBACK can be implemented for -ALL- the interrupts
  //
  // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
  //
  uint8_t OnOff8 = 0, OutPin8 = 255;
  //
  switch(gpio) {

    case G_pinINCRbttn8:
      // event management code
      if (Gvlt_Event8 < 255) {
        Gvlt_Event8 += 1;
        OnOff8 = 1, OutPin8 = 18;
        // the following line of code, -DISABLE- the INTERRUPT
        // ATTENTION: furthermore, to become RELIABLE, IT MUST NOT BE inserted
        // in a generic position at the end of this function: instead it
        // MUST RESIDE INSIDE of THIS event handling code
        gpio_set_irq_enabled_with_callback(gpio, 0x04, false, &Bttn_clbk);
        // NOTE: in the function -gpio_set_irq_enabled_with_callback()-
        //       the SECOND parameter is the > event_mask < [0x04 --> FALLING]
        //       the THIRD parameter is the - Disable(false) [Enable(true)] - flag
      } // if
      break;

    case G_pinDECRbttn8:
      // event management code
      if (Gvlt_Event8 > 0) {
        Gvlt_Event8 -= 1;
        OnOff8 = 1, OutPin8 = 19;
        // the following line of code, -DISABLE- the INTERRUPT
        // ATTENTION: furthermore, to become RELIABLE, IT MUST NOT BE inserted
        // in a generic position at the end of this function: instead it
        // MUST RESIDE INSIDE of THIS event handling code
        gpio_set_irq_enabled_with_callback(gpio, 0x04, false, &Bttn_clbk);
        // NOTE: in the function -gpio_set_irq_enabled_with_callback()-
        //       the SECOND parameter is the > event_mask < [0x04 --> FALLING]
        //       the THIRD parameter is the - Disable(false) [Enable(true)] - flag
      } // if
      break;

    default:
      OnOff8 = 0;
      break;
  }
  //
  if (OnOff8 > 0) digitalWrite(OutPin8, OnOff8);
  //
} // Bttn_clbk()

// **************************************************************************


void setup() {
  //
  Serial1.begin(115200);
  while (!Serial1);
  //
  Serial1.println("\nsetup started...\n");
  //
  pinMode(G_pinINCRbttn8, INPUT); // RED  bttn. INCR.
  pinMode(G_pinDECRbttn8, INPUT); // BLUE bttn. DECR.
  //
  // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
  //
  // only ONE CALLBACK can be implemented for -ALL- the interrupts
  //
  // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
  //
  // NOTE, in the function -gpio_set_irq_enabled_with_callback()-:
  // A) the SECOND parameter is the > event_mask <
  //    (which event will trigger the interrupt):
  //     0 - GPIO_IRQ_LEVEL_LOW  => 0x1u Continuously while level is low
  //     1 - GPIO_IRQ_LEVEL_HIGH => 0x2u Continuously while level is high
  //     2 - GPIO_IRQ_EDGE_FALL  => 0x4u On each transition from high to low
  //     3 - GPIO_IRQ_EDGE_RISE  => 0x8u On each transition from low to high
  // B) the THIRD parameter is the - Enable(1) or Disable(0) - flag
  gpio_set_irq_enabled_with_callback(G_pinINCRbttn8, 0x04, true, &Bttn_clbk);
  gpio_set_irq_enabled_with_callback(G_pinDECRbttn8, 0x04, true, &Bttn_clbk);
  // interrupt triggered by FALLING edge [2 - GPIO_IRQ_EDGE_FALL => 0x04)]
  // NOTE: in the function -gpio_set_irq_enabled_with_callback()-
  //       the SECOND parameter is the > event_mask < [0x04 --> FALLING]
  //       the THIRD parameter is the - Enable(true) [Disable(false)] - flag
  //
  // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
  //
  // only ONE CALLBACK can be implemented for -ALL- the interrupts
  //
  // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
  //
  pinMode(18, OUTPUT);
  pinMode(19, OUTPUT);
  // brute force lit ALL led...just to see if all works :)
  digitalWrite(18, 1);
  digitalWrite(19, 1);
  delay(1000);
  // brute force zeroing ALL led
  digitalWrite(18, 0);
  digitalWrite(19, 0);
  //
  Serial1.println("... setup ended.\n");
  //
} // setup()


void loop() {
  //
  // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
  //
  // only ONE CALLBACK can be implemented for -ALL- the interrupts
  //
  // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
  //
  static uint8_t oldEvnt8 = 0;
  //
  if (Gvlt_Event8 != oldEvnt8) {
    // re-enables the interrupt that generated the event
    if (Gvlt_Event8 < oldEvnt8) {
      gpio_set_irq_enabled_with_callback(G_pinDECRbttn8, 0x04, true, &Bttn_clbk);
    } else if (Gvlt_Event8 > oldEvnt8) {
      gpio_set_irq_enabled_with_callback(G_pinINCRbttn8, 0x04, true, &Bttn_clbk);
    } // if-else
    //
    oldEvnt8 = Gvlt_Event8;
    Serial1.print("Gvlt_Event8 ="); Serial1.println(Gvlt_Event8);
    //
    // NOTE: in the function -gpio_set_irq_enabled_with_callback()-
    //       the THIRD parameter is the - Enable(true) [Disable(false)] - flag
    //
    // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
    //
    // only ONE CALLBACK can be implemented for -ALL- the interrupts
    //
    // ::::  WARNING  ::::  ::::  WARNING  ::::  ::::  WARNING  ::::
    //
    // brute force zeroing ALL led
    delay(300);
    digitalWrite(18, 0);
    digitalWrite(19, 0);
    //
  } // if
  //
  delay(100);
  //
} // loop()