#include <Arduino_FreeRTOS.h>

#include <semphr.h>  // add the FreeRTOS functions for Semaphores (or Flags).

// Declare a mutex Semaphore Handle which we will use to manage the Serial Port.

// It will be used to ensure only only one Task is accessing this resource at any time.

SemaphoreHandle_t xSerialSemaphore;

// define two Tasks for DigitalRead & AnalogRead

void TaskDigitalRead( void *pvParameters );

void TaskAnalogRead( void *pvParameters );

// the setup function runs once when you press reset or power the board

void setup() {

  // initialize serial communication at 9600 bits per second:

  Serial.begin(9600);

  while (!Serial) {

    ; // wait for serial port to connect.

  }

  // Semaphores are useful to stop a Task proceeding, where it should be paused to wait,

  // because it is sharing a resource, such as the Serial port.

  // Semaphores should only be used whilst the scheduler is running, but we can set it up here.

  if ( xSerialSemaphore == NULL )  // Check to confirm that the Serial Semaphore has not already been created.

  {

    xSerialSemaphore = xSemaphoreCreateMutex();  // Create a mutex semaphore we will use to manage the Serial Port

    if ( ( xSerialSemaphore ) != NULL )

      xSemaphoreGive( ( xSerialSemaphore ) );  // Make the Serial Port available for use, by "Giving" the Semaphore.

  }

  // Now set up two Tasks to run independently.

  xTaskCreate(

    TaskDigitalRead

    ,  (const portCHAR *)"DigitalRead"  // A name just for humans

    ,  128  // This stack size can be checked & adjusted by reading the Stack Highwater

    ,  NULL

    ,  2  // Priority, with 3 (configMAX_PRIORITIES - 1) being the highest, and 0 being the lowest.

    ,  NULL );

  xTaskCreate(

    TaskAnalogRead

    ,  (const portCHAR *) "AnalogRead"

    ,  128  // Stack size

    ,  NULL

    ,  1  // Priority

    ,  NULL );

  // Now the Task scheduler, which takes over control of scheduling individual Tasks, is automatically started.

}

void loop()

{

  // Empty. Things are done in Tasks.

}

/*--------------------------------------------------*/

/*---------------------- Tasks ---------------------*/

/*--------------------------------------------------*/

void TaskDigitalRead( void *pvParameters __attribute__((unused)) )  // This is a Task.

{

  /*

    DigitalReadSerial

    Reads a digital input on pin 2, prints the result to the serial monitor

    This example code is in the public domain.

  */

  // digital pin 2 has a pushbutton attached to it. Give it a name:

  uint8_t pushButton = I0_0;

  // make the pushbutton's pin an input:

  pinMode(pushButton, INPUT);

  for (;;) // A Task shall never return or exit.

  {

    // read the input pin:

    int buttonState = digitalRead(pushButton);

    // See if we can obtain or "Take" the Serial Semaphore.

    // If the semaphore is not available, wait 5 ticks of the Scheduler to see if it becomes free.

    if ( xSemaphoreTake( xSerialSemaphore, ( TickType_t ) 5 ) == pdTRUE )

    {

      // We were able to obtain or "Take" the semaphore and can now access the shared resource.

      // We want to have the Serial Port for us alone, as it takes some time to print,

      // so we don't want it getting stolen during the middle of a conversion.

      // print out the state of the button:

      Serial.println(buttonState);

      xSemaphoreGive( xSerialSemaphore ); // Now free or "Give" the Serial Port for others.

    }

    vTaskDelay(1);  // one tick delay (15ms) in between reads for stability

  }

}

void TaskAnalogRead( void *pvParameters __attribute__((unused)) )  // This is a Task.

{

  for (;;)

  {

    // read the input on analog pin 0:

    int sensorValue = analogRead(I0_1);

    // See if we can obtain or "Take" the Serial Semaphore.

    // If the semaphore is not available, wait 5 ticks of the Scheduler to see if it becomes free.

    if ( xSemaphoreTake( xSerialSemaphore, ( TickType_t ) 5 ) == pdTRUE )

    {

      // We were able to obtain or "Take" the semaphore and can now access the shared resource.

      // We want to have the Serial Port for us alone, as it takes some time to print,

      // so we don't want it getting stolen during the middle of a conversion.

      // print out the value you read:

      Serial.println(sensorValue);

      xSemaphoreGive( xSerialSemaphore ); // Now free or "Give" the Serial Port for others.

    }

    vTaskDelay(1);  // one tick delay (15ms) in between reads for stability

  }

}