How to run FreeRTOS on TM4C129EXL?

Question

I am working on a C project for the university where a CoAP server is to be hosted on a TM4C129EXL. It is particularly important to choose a FreeRTOS operating system. Unfortunately, I had to learn that Texas Instruments has stopped supporting FreeRTOS. There are no options for me to switch to another operating system. It is for this reason that I turn to you.

I'm looking for a sample program in which Free RTOS is executed on a TM4C129EXL board. In the best case, I would be happy about a Code Composer Studio Project, as this is the IDE we work with from the university.

If you do not have any sample code available, I would be happy to receive any other information regarding FreeRTOS and CoAP of course with reference to the TM4C129EXL.

Answer 1

You did not specify if you had any requirements in terms of FreeRTOS version, but you can either:

• use the demo provided in file SW-EK-TM4C1294XL-2.1.4.178.exe available on TI WEB site as is - you will find it in directory examples\boards\ek-tm4c1294xl-boostxl-senshub\senshub_iot
• use this example as a basis to use a more recent version of FreeRTOS: you just would have to replace FreeRTOS source code by the most recent one, and maybe to modify some code in the demo: some function names/signatures may have changed across major versions.

The procedure hereafter describes step by step how to create a minimalist FreeRTOS program with Code Composer Studio 10.3.0 and FreeRTOS v202104.00 in a Windows 10 environment using the second approach. You may have to adjust the drive letter to you specific setup, I am using D: for the purpose of this example..

• Download Code Composer Studio 10.3.0, FreeRTOS v202104.00 and SW-EK-TM4C1294XL-2.1.4.178.exe.

• Install Code Composer Studio with support for the Tiva-C MCU familly. When prompted for a workspace name, specify D:\ti\workspace_v10.

• Unzip FreeRTOSv202104.00.zipinto D:\.

• Unzip SW-EK-TM4C1294XL-2.1.4.178.exe into D:\SW-EK-TM4C1294XL-2.1.4.178.

• Launch CCS

• Use the menu item File/New/CCS Project, and create an 'Empty Project (with main.c).

[]

• Click on the Finishbutton.
• Create the following directories:
  D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\driverlib
D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\inc
D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\FreeRTOS-Kernel
D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\FreeRTOS-Kernel\include
D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\FreeRTOS-Kernel\portable\GCC
D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\FreeRTOS-Kernel\portable\GCC\ARM_CM4F
D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\FreeRTOS-Kernel\portable\MemMang
• Copy D:\SW-EK-TM4C1294XL-2.1.4.178\examples\boards\ek-tm4c1294xl-boostxl-senshub\senshub_iot\FreeRTOSConfig.h into D:\ti\workspace_v10\TM4C129EXL-FreeRTOS
• Copy all .h files from D:\SW-EK-TM4C1294XL-2.1.4.178\driverlib into D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\driverlib.
• Copy D:\SW-EK-TM4C1294XL-2.1.4.178\driverlib\gcc\libdriver.a into D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\driverlib.
• Copy all .hfiles from D:\SW-EK-TM4C1294XL-2.1.4.178\inc into D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\inc.
• Copy all files present in D:\FreeRTOSv202104.00\FreeRTOS\Source\include into D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\FreeRTOS-Kernel\include.
• Copy all .cfiles present in D:\FreeRTOSv202104.00\FreeRTOS\Source into D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\FreeRTOS-Kernel.
• Copy all file present in D:\FreeRTOSv202104.00\FreeRTOS\Source\portable\GCC\ARM_CM4F into D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\FreeRTOS-Kernel\portable\GCC\ARM_CM4F
• Copy D:\FreeRTOSv202104.00\FreeRTOS\Source\portable\MemMang\heap_4.c into D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\FreeRTOS-Kernel\portable\MemMang.
• Edit D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\main.c, and replace its content by:

#include "FreeRTOS.h"
#include "task.h"

extern void prvSetupHardware();
extern void main_blinky();

int main(void)
{
    /* Configure the hardware ready to run the demo. */
    prvSetupHardware();

    main_blinky();

    /* Don't expect to reach here. */
    return 0;
}

void vApplicationStackOverflowHook( TaskHandle_t xTask, char *pcTaskName)
{
    while(1)
    {
    }
}

• Create a new file named D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\blinky.c with the following content:

#include <stdbool.h>
#include <stdint.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "inc/hw_ints.h"
#include "driverlib/debug.h"
#include "driverlib/gpio.h"
#include "driverlib/sysctl.h"
#include "FreeRTOS.h"
#include "task.h"
#include "sysctl.h"

static void prvLedToggleTask();

/* Priorities at which the tasks are created. */
#define mainTOGGLE_LED_PRIORITY         ( tskIDLE_PRIORITY + 1 )
#define TOGGLE_LED_DELAY_MS             200

void main_blinky()
{
    /* create task */
    xTaskCreate( prvLedToggleTask, "LED", configMINIMAL_STACK_SIZE, NULL, mainTOGGLE_LED_PRIORITY, NULL );

    /* Start the tasks and timer running. */
    vTaskStartScheduler();

}

static void prvLedToggleTask( void *pvParameters )
{
    // Remove compiler warning about unused parameter. */
    ( void ) pvParameters;

    for( ;; )
    {
        //
        // Turn on the LED.
        //
        GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, GPIO_PIN_0);

        // Wait a bit
        vTaskDelay( TOGGLE_LED_DELAY_MS);

        //
        // Turn off the LED.
        //
        GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, 0x0);

        // Wait a bit
        vTaskDelay( TOGGLE_LED_DELAY_MS );
    }
}

uint32_t g_ui32SysClock;

void prvSetupHardware()
{
    // Configure PLL
    g_ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ |
                                         SYSCTL_OSC_MAIN |
                                         SYSCTL_USE_PLL |
                                         SYSCTL_CFG_VCO_480), 120000000);
    //
    // Enable the GPIO port that is used for the on-board LED.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPION);

    //
    // Check if the peripheral access is enabled.
    //
    while(!SysCtlPeripheralReady(SYSCTL_PERIPH_GPION))
    {
    }

    //
    // Enable the GPIO pin for the LED (PN0).  Set the direction as output, and
    // enable the GPIO pin for digital function.
    //
    GPIOPinTypeGPIOOutput(GPIO_PORTN_BASE, GPIO_PIN_0);
}

• Edit tm4c1294ncpdt_startup_ccs_gcc.c: add the following lines after the line containing static void IntDefaultHandler(void);

extern void xPortPendSVHandler(void);
extern void vPortSVCHandler(void);
extern void xPortSysTickHandler(void);

The resulting code should look like:

void ResetISR(void);
static void NmiSR(void);
static void FaultISR(void);
static void IntDefaultHandler(void);

extern void xPortPendSVHandler(void);
extern void vPortSVCHandler(void);
extern void xPortSysTickHandler(void);

• Edit tm4c1294ncpdt_startup_ccs_gcc.c: replace the default interrupt handler by the FreeRTOS one in array g_pfnVectors[].
  Original code:

  void (* const g_pfnVectors[])(void) =
{
    (void (*)(void))((uint32_t)pui32Stack + sizeof(pui32Stack)),
                                            // The initial stack pointer
    ResetISR,                               // The reset handler
    NmiSR,                                  // The NMI handler
    FaultISR,                               // The hard fault handler
    IntDefaultHandler,                      // The MPU fault handler
    IntDefaultHandler,                      // The bus fault handler
    IntDefaultHandler,                      // The usage fault handler
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    IntDefaultHandler,                      // SVCall handler
    IntDefaultHandler,                      // Debug monitor handler
    0,                                      // Reserved
    IntDefaultHandler,                      // The PendSV handler
    IntDefaultHandler,                      // The SysTick handler

Resulting code:

void (* const g_pfnVectors[])(void) =
{
    (void (*)(void))((uint32_t)pui32Stack + sizeof(pui32Stack)),
                                            // The initial stack pointer
    ResetISR,                               // The reset handler
    NmiSR,                                  // The NMI handler
    FaultISR,                               // The hard fault handler
    IntDefaultHandler,                      // The MPU fault handler
    IntDefaultHandler,                      // The bus fault handler
    IntDefaultHandler,                      // The usage fault handler
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    vPortSVCHandler,                        // SVCall handler
    IntDefaultHandler,                      // Debug monitor handler
    0,                                      // Reserved
    xPortPendSVHandler,                     // The PendSV handler
    xPortSysTickHandler,                    // The SysTick handler

• Edit the project properties for the GCC Compiler directories, and add the following directories:
  ${workspace_loc:/${ProjName}/FreeRTOS-Kernel/include}
${workspace_loc:/${ProjName}/FreeRTOS-Kernel/portable/GCC/ARM_CM4F}
${workspace_loc:/${ProjName}
${workspace_loc:/${ProjName}/driverlib}
  and click on the Apply and close button.

• Edit D:\ti\workspace_v10\TM4C129EXL-FreeRTOS\FreeRTOSConfig.h and delete the following lines:

#define configGENERATE_RUN_TIME_STATS       1
#define portCONFIGURE_TIMER_FOR_RUN_TIME_STATS()                              \
                                            g_vulRunTimeStatsCountValue = 0ul
#define portGET_RUN_TIME_COUNTER_VALUE()    g_vulRunTimeStatsCountValue

• Edit the GCC compiler Command-line pattern and add the -mfloat-abi=hard option after ${flags} in the Command-line pattern:
  ${command} ${flags} -mfloat-abi=hard ${output_flag}${output} ${inputs}

• Edit the GNU Linker Command-line pattern and add the -mfloat-abi=hard option after ${flags}:>br/> ${command} ${flags} -mfloat-abi=hard ${output_flag}${output} ${inputs}

• Edit the GCC Linker libraries: add libdriver.a to the -l option, and ${workspace_loc:/${ProjName}/driverlib} to the -L option, then click on the Apply and close button.

• Build your project - it should build without any errors.
• Flash your project by running it.

In my case, I had to stop the project and to press the board resetbutton in order to the program to start.

Finally, the LED should start blinking every 200ms.

The complete list of files in the project once the project 'cleaned' should ultimately be:

Folder PATH listing for volume DATA
Volume serial number is 0E12-BCA2
D:.
|   .ccsproject
|   .cproject
|   .project
|   blinky.c
|   FreeRTOSConfig.h
|   main.c
|   tm4c1294ncpdt.lds
|   tm4c1294ncpdt_startup_ccs_gcc.c
|   
+---.settings
|       org.eclipse.cdt.codan.core.prefs
|       org.eclipse.cdt.debug.core.prefs
|       org.eclipse.core.resources.prefs
|       
+---Debug
|   |   ccsObjs.opt
|   |   makefile
|   |   objects.mk
|   |   sources.mk
|   |   subdir_rules.mk
|   |   subdir_vars.mk
|   |   TM4C129EXL-FreeRTOS.map
|   |   
|   +---driverlib
|   |       subdir_rules.mk
|   |       subdir_vars.mk
|   |       
|   \---FreeRTOS-Kernel
|       |   subdir_rules.mk
|       |   subdir_vars.mk
|       |   
|       \---portable
|           +---GCC
|           |   \---ARM_CM4F
|           |           subdir_rules.mk
|           |           subdir_vars.mk
|           |           
|           \---MemMang
|                   subdir_rules.mk
|                   subdir_vars.mk
|                   
+---driverlib
|       adc.h
|       aes.h
|       can.h
|       comp.h
|       cpu.h
|       crc.h
|       debug.h
|       des.h
|       eeprom.h
|       emac.h
|       epi.h
|       flash.h
|       fpu.h
|       gpio.h
|       hibernate.h
|       i2c.h
|       interrupt.h
|       lcd.h
|       libdriver.a
|       mpu.h
|       onewire.h
|       pin_map.h
|       pwm.h
|       qei.h
|       rom.h
|       rom_map.h
|       rtos_bindings.h
|       shamd5.h
|       ssi.h
|       sw_crc.h
|       sysctl.h
|       sysexc.h
|       systick.h
|       timer.h
|       uart.h
|       udma.h
|       usb.h
|       watchdog.h
|       
+---FreeRTOS-Kernel
|   |   croutine.c
|   |   event_groups.c
|   |   list.c
|   |   queue.c
|   |   stream_buffer.c
|   |   tasks.c
|   |   timers.c
|   |   
|   +---include
|   |       atomic.h
|   |       croutine.h
|   |       deprecated_definitions.h
|   |       event_groups.h
|   |       FreeRTOS.h
|   |       list.h
|   |       message_buffer.h
|   |       mpu_prototypes.h
|   |       mpu_wrappers.h
|   |       portable.h
|   |       projdefs.h
|   |       queue.h
|   |       semphr.h
|   |       StackMacros.h
|   |       stack_macros.h
|   |       stdint.readme
|   |       stream_buffer.h
|   |       task.h
|   |       timers.h
|   |       
|   \---portable
|       +---GCC
|       |   \---ARM_CM4F
|       |           port.c
|       |           portmacro.h
|       |           
|       \---MemMang
|               heap_4.c
|               
\---inc
        asmdefs.h
        hw_adc.h
        hw_aes.h
        hw_can.h
        hw_ccm.h
        hw_comp.h
        hw_des.h
        hw_eeprom.h
        hw_emac.h
        hw_epi.h
        hw_fan.h
        hw_flash.h
        hw_gpio.h
        hw_hibernate.h
        hw_i2c.h
        hw_ints.h
        hw_lcd.h
        hw_memmap.h
        hw_nvic.h
        hw_onewire.h
        hw_pwm.h
        hw_qei.h
        hw_shamd5.h
        hw_ssi.h
        hw_sysctl.h
        hw_sysexc.h
        hw_timer.h
        hw_types.h
        hw_uart.h
        hw_udma.h
        hw_usb.h
        hw_watchdog.h
        tm4c1294ncpdt.h