In “Tutorial: Blinky with NXP Kinetis SDK V2.0 and Processor Expert” I used Processor Expert components with the NXP Kinetis SDK to blink some LEDs. This tutorial extends the earlier project and adds FreeRTOS.

Outline

In this tutorial I show how to add FreeRTOS to the ‘Mother’ Processor Expert project and to add a ‘blinky’ task with FreeRTOS. I’m using the Kinetis SDK V2.0 for the NXP FRDM-K22F board with the Eclipse based Kinetis Design Studio V3.2.0. As application a ‘blinky’ task is added to the project.

FreeRTOS Component

Adding FreeRTOS with components is very easy: simply add the McuOnEclipse FreeRTOS component to the mother project:

Check the ARM Family/core selection in the FreeRTOS component to match the microcontroller used:

For an SDK project, I have to enable the SDK option in the FreeRTOS settings:

With this code can be generated by Processor Expert and used in the Kinetis SDK project. This is the topic of the next steps.

FreeRTOS Hooks

Because the component has hooks enabled, I add the following lines to main.c: they add empty/default RTOS hooks for when I have them enabled in FreeRTOSConfig.h.

#include "FreeRTOS.h"
#include "FRTOS1.h"
void FRTOS1_vApplicationStackOverflowHook(xTaskHandle pxTask, char *pcTaskName) {
/* This will get called if a stack overflow is detected during the context
   switch.  Set configCHECK_FOR_STACK_OVERFLOWS to 2 to also check for stack
   problems within nested interrupts, but only do this for debug purposes as
   it will increase the context switch time. */
  (void)pxTask;
  (void)pcTaskName;
  taskDISABLE_INTERRUPTS();
  /* Write your code here ... */
  for(;;) {}
}

void FRTOS1_vApplicationTickHook(void) {
  /* Called for every RTOS tick. */
  /* Write your code here ... */
}

void FRTOS1_vApplicationIdleHook(void) {
  /* Called whenever the RTOS is idle (from the IDLE task).
     Here would be a good place to put the CPU into low power mode. */
  /* Write your code here ... */
}

void FRTOS1_vApplicationMallocFailedHook(void) {
  /* Called if a call to pvPortMalloc() fails because there is insufficient
     free memory available in the FreeRTOS heap.  pvPortMalloc() is called
     internally by FreeRTOS API functions that create tasks, queues, software
     timers, and semaphores.  The size of the FreeRTOS heap is set by the
     configTOTAL_HEAP_SIZE configuration constant in FreeRTOSConfig.h. */
  taskDISABLE_INTERRUPTS();
  /* Write your code here ... */
  for(;;) {}
}

Like any other component, I initialize the component in main() first with:

NEW version

Next I add the code to create a task into main() followed by starting the scheduler:

  FRTOS1_Init();
  if (xTaskCreate(AppTask, "App", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY+1, NULL) != pdPASS) {
    for(;;){} /* error */
  }
  vTaskStartScheduler();

Finally, the code for the blinky application task gets added:

static void AppTask(void *pvParameters) {
  (void)pvParameters;
  for(;;) {
    LED1_Neg();
    vTaskDelay(pdMS_TO_TICKS(100));
  }
}

Below is the full source code of main.c:

/*
 * Copyright (c) 2013 - 2016, Freescale Semiconductor, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * o Redistributions of source code must retain the above copyright notice, this list
 * of conditions and the following disclaimer.
 *
 * o Redistributions in binary form must reproduce the above copyright notice, this
 * list of conditions and the following disclaimer in the documentation and/or
 * other materials provided with the distribution.
 *
 * o Neither the name of Freescale Semiconductor, Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * This is template for main module created by New Kinetis SDK 2.x Project Wizard. Enjoy!
 **/

#include "board.h"
#include "pin_mux.h"
#include "clock_config.h"

#include "LED1.h"
#include "LED2.h"
#include "LED3.h"
#include "WAIT1.h"
#include "fsl_port.h"

#define USE_FREERTOS 1 /* turns on using FreeRTOS */

#if USE_FREERTOS
#include "FreeRTOS.h"
#include "FRTOS1.h"

void FRTOS1_vApplicationStackOverflowHook(xTaskHandle pxTask, char *pcTaskName) {
 /* This will get called if a stack overflow is detected during the context
 switch. Set configCHECK_FOR_STACK_OVERFLOWS to 2 to also check for stack
 problems within nested interrupts, but only do this for debug purposes as
 it will increase the context switch time. */
 (void)pxTask;
 (void)pcTaskName;
 taskDISABLE_INTERRUPTS();
 /* Write your code here ... */
 for(;;) {}
}

void FRTOS1_vApplicationTickHook(void) {
 /* Called for every RTOS tick. */
 /* Write your code here ... */
}

void FRTOS1_vApplicationIdleHook(void) {
 /* Called whenever the RTOS is idle (from the IDLE task).
 Here would be a good place to put the CPU into low power mode. */
 /* Write your code here ... */
}

void FRTOS1_vApplicationMallocFailedHook(void)
{
 /* Called if a call to pvPortMalloc() fails because there is insufficient
 free memory available in the FreeRTOS heap. pvPortMalloc() is called
 internally by FreeRTOS API functions that create tasks, queues, software
 timers, and semaphores. The size of the FreeRTOS heap is set by the
 configTOTAL_HEAP_SIZE configuration constant in FreeRTOSConfig.h. */
 taskDISABLE_INTERRUPTS();
 /* Write your code here ... */
 for(;;) {}
}
#endif

static void AppTask(void *pvParameters) {
 (void)pvParameters;
 for(;;) {
 LED1_Neg();
 vTaskDelay(pdMS_TO_TICKS(100));
 }
}

/*!
 * @brief Application entry point.
 */

int main(void) {
 /* Init board hardware. */
 BOARD_InitPins();
 BOARD_BootClockRUN();
 BOARD_InitDebugConsole();

 /* init components */
 LED1_Init();
 LED2_Init();
 LED3_Init();

 /* run the code */
#if USE_FREERTOS
 FRTOS1_Init();
 if (xTaskCreate(AppTask, "App", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY+1, NULL) != pdPASS) {
 for(;;){} /* error */
 }
 vTaskStartScheduler();
#else
 for(;;) {
#if 0
 LED1_Neg();
 LED2_Neg();
 LED3_Neg();
#else
 LED1_On(); WAIT1_Waitms(500); LED1_Off();
 LED2_On(); WAIT1_Waitms(500); LED2_Off();
 LED3_On(); WAIT1_Waitms(500); LED3_Off();
#endif
 }
#endif

 for(;;) { /* Infinite loop to avoid leaving the main function */
 __asm("NOP"); /* something to use as a breakpoint stop while looping */
 }
}

Compile/build and debug that project, and you should have a blinky with FreeRTOS:

Summary

With this approach I have now an easy way to add FreeRTOS with a Processor Expert component to the Kinetis SDK V2.0. FreeRTOS is already included in the Kinetis SDK, but the Processor Expert component gives me a graphical configuration plus includes all the great extensions e.g. for tickless idle low power mode, Segger SystemView or Percepio Tracealizer.

The project and source files are available on GitHub (see ‘Links’ below).

Happy RTOSing 🙂

Links

• Concept about how to use Processor Expert with SDK V2.0: Mother of Components: Processor Expert with NXP Kinetis SDK V2.0 Projects
• Blinky Tutorial: Tutorial: Blinky with NXP Kinetis SDK V2.0 and Processor Expert
• Projects on GitHub: https://github.com/ErichStyger/mcuoneclipse/tree/master/Examples/KDS/FRDM-K22F/FRDM-K22F_PEx_for_SDK_v2.0 and https://github.com/ErichStyger/mcuoneclipse/tree/master/Examples/KDS/FRDM-K22F/FRDM-K22F_SDK_V2.0_PEx