xCORE-200 Multichannel Audio Platform simple gpio 1

main.xc

/*
Simple gpio is based on xmos an00155 for xCORE-200 eXplorerKIT.
Here, I'm applying the code on MCA.

Observe that instead of using the led matrix on MCA, I'm using 
a single bit port normally used for OPT_RX (which I monitor 
with an oscilloscope).

I have built with unchanged Makefile Target, i.e. xCORE-200 Explorer Kit

Running: Press button 1 and observe the voltage level on OPT_RX.
*/

#include <xs1.h>
#include <platform.h>
#include <gpio.h>

// GPIO port declarations
on tile[1] : in port  mca_btns = XS1_PORT_4B;  //btn1 on P4B0...switch on P4B3
on tile[1] : out port mca_leds = XS1_PORT_1O;  //OPT_RX NOT led

// GPIO handler routine
void gpio_mca_handler(client input_gpio_if button_1, client output_gpio_if led_1){
    // LED state
    unsigned int led_state = 0;

    // Initial button event state, active low
    button_1.event_when_pins_eq(0);

    while (1) {
      select {
        // Triggered by events on button 1
        case button_1.event():
          if (button_1.input() == 0) {
            led_state = ~led_state;
            led_1.output(led_state);
            // Set button event state to active high for debounce
            button_1.event_when_pins_eq(1);
          } else {
            // Debounce button
            delay_milliseconds(50);
            button_1.event_when_pins_eq(0);
          }
          break;
      }
    }
}

// The main() function runs a single task which takes the gpio interfaces as parameters
int main() {
  input_gpio_if  i_mca_buttons[4];
  output_gpio_if i_mca_leds[1];  //Actually OPT_RX, NOT the led matrix
 
  par {
     on tile[1] : input_gpio_with_events(i_mca_buttons, 4, mca_btns, null);
     on tile[1] : output_gpio(i_mca_leds, 1, mca_leds, null);
     on tile[0] : gpio_mca_handler(i_mca_buttons[0],
                                   i_mca_leds[0]);
  }

   return 0;
}