Creating a Custom Project for RP2040-SMP

1. Project Setup

After running the FreeRTOS-SMP-Demos, you have a basic understanding of how SMP operates. Now, create your own project and compile it.

Follow the enstructions in "Creating Your Own Pico Project" to set up the pico_smp project. Create pico_smp.c and input:

#include <stdio.h>
#include "pico/stdlib.h"

int main()
{
    setup_default_uart();
    while(1) {
        printf("Hello World!\r\n");
        sleep_ms(1000);
    }
    return 0;
}

Create CMakeLists.txt:

cmake_minimum_required(VERSION 3.13)

include(pico_sdk_import.cmake)

project(pico_smp C CXX ASM)

set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 17)

pico_sdk_init()

add_executable(pico_smp
    pico_smp.c
)

pico_add_extra_outputs(pico_smp)
target_link_libraries(pico_smp pico_stdlib)

In the pico_freertos_smp directory, run:

$ mkdir build && cd build
$ cmake ..
$ make

Verify that the compilation works correctly.

2. Downloading FreeRTOS-SMP Source Code

Download the smp branch using git submodule:

$ git submodule add -b smp https://github.com/FreeRTOS/FreeRTOS-Kernel

After downloading, check the RP2040-SMP adaptation in the FreeRTOS-Kernel/portable/ThirdParty/GCC/RP2040 directory. Based on the README.md file, copy the FreeRTOS_Kernel_import.cmake file into your project diretcory and include it in the CMakeLists.txt file.

Modifying the pico-smp Project

Update CMakeLists.txt to include include(FreeRTOS_Kernel_import.cmake) since the FreeRTOS-Kernel is now a submodule within the current project directory.

cmake_minimum_required(VERSION 3.13)

include(pico_sdk_import.cmake)

include(FreeRTOS-Kernel/portable/ThirdParty/GCC/RP2040/FreeRTOS_Kernel_import.cmake)

project(pico_smp C CXX ASM)

set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 17)

pico_sdk_init()

add_executable(pico_smp
    pico_smp.c
)

target_link_libraries(pico_smp pico_stdlib FreeRTOS-Kernel FreeRTOS-Kernel-Heap4)
include_directories(${CMAKE_CURRENT_LIST_DIR})

pico_add_extra_outputs(pico_smp)

Add code related to SMP and modify the main() function to create two tasks, assigning task0 to core0 and task1 to core1.
Call vTaskStartScheduler() to start the scheduler.

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

void task0(void *param)
{
    static uint32_t cnt = 0;
    while (1) {
        printf("%s cnt: %d\n", __FUNCTION__, cnt ++);
        printf("task %s is runing in core %d\r\n", __FUNCTION__, portGET_CORE_ID());
        vTaskDelay(1000);
    }
}

void task1(void *param)
{
    static uint32_t cnt = 0;
    while (1) {
        printf("%s cnt: %d\n", __FUNCTION__, cnt ++);
        printf("task %s is runing in core %d\r\n", __FUNCTION__, portGET_CORE_ID());
        vTaskDelay(1000);
    }
}

int main()
{
    setup_default_uart();

    TaskHandle_t task0_Handle = NULL;
    xTaskCreate(task0, "task0", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, &task0_Handle);
    UBaseType_t task0_CoreAffinityMask = (1 << 0);
    vTaskCoreAffinitySet(task0_Handle, task0_CoreAffinityMask); 

    TaskHandle_t task1_Handle = NULL;
    xTaskCreate(task1, "task1", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 2, &task1_Handle);
    UBaseType_t task1_CoreAffinityMask = (1 << 1);
    vTaskCoreAffinitySet(task1_Handle, task1_CoreAffinityMask); 

    vTaskStartScheduler();

    return 0;
}

Ensure the following macros are anabled:

#define configRUN_MULTIPLE_PRIORITIES           1
#define configUSE_CORE_AFFINITY                 1

Add FreeRTOSConfig.h:

/*
 * FreeRTOS V202107.00
 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * http://www.FreeRTOS.org
 * http://aws.amazon.com/freertos
 *
 * 1 tab == 4 spaces!
 */

#ifndef FREERTOS_CONFIG_H
#define FREERTOS_CONFIG_H

/*-----------------------------------------------------------
 * Application specific definitions.
 *
 * These definitions should be adjusted for your particular hardware and
 * application requirements.
 *
 * THESE PARAMETERS ARE DESCRIBED WITHIN THE 'CONFIGURATION' SECTION OF THE
 * FreeRTOS API DOCUMENTATION AVAILABLE ON THE FreeRTOS.org WEB SITE.
 *
 * See http://www.freertos.org/a00110.html
----------------------------------------------------------*/

/* Scheduler Related */
#define configUSE_PREEMPTION                    1
#define configUSE_TICKLESS_IDLE                 0
#define configUSE_IDLE_HOOK                     0
#define configUSE_TICK_HOOK                     0
#define configTICK_RATE_HZ                      ( ( TickType_t ) 1000 )
#define configMAX_PRIORITIES                    32
#define configMINIMAL_STACK_SIZE                ( configSTACK_DEPTH_TYPE ) 256
#define configUSE_16_BIT_TICKS                  0

#define configIDLE_SHOULD_YIELD                 1

/* Synchronization Related */
#define configUSE_MUTEXES                       1
#define configUSE_RECURSIVE_MUTEXES             1
#define configUSE_APPLICATION_TASK_TAG          0
#define configUSE_COUNTING_SEMAPHORES           1
#define configQUEUE_REGISTRY_SIZE               8
#define configUSE_QUEUE_SETS                    1
#define configUSE_TIME_SLICING                  1
#define configUSE_NEWLIB_REENTRANT              0
#define configENABLE_BACKWARD_COMPATIBILITY     0
#define configNUM_THREAD_LOCAL_STORAGE_POINTERS 5

/* System */
#define configSTACK_DEPTH_TYPE                  uint32_t
#define configMESSAGE_BUFFER_LENGTH_TYPE        size_t

/* Memory allocation related definitions. */
#define configSUPPORT_STATIC_ALLOCATION         0
#define configSUPPORT_DYNAMIC_ALLOCATION        1
#define configTOTAL_HEAP_SIZE                   (128*1024)
#define configAPPLICATION_ALLOCATED_HEAP        0

/* Hook function related definitions. */
#define configCHECK_FOR_STACK_OVERFLOW          0
#define configUSE_MALLOC_FAILED_HOOK            0
#define configUSE_DAEMON_TASK_STARTUP_HOOK      0

/* Run time and task stats gathering related definitions. */
#define configGENERATE_RUN_TIME_STATS           0
#define configUSE_TRACE_FACILITY                1
#define configUSE_STATS_FORMATTING_FUNCTIONS    0

/* Co-routine related definitions. */
#define configUSE_CO_ROUTINES                   0
#define configMAX_CO_ROUTINE_PRIORITIES         1

/* Software timer related definitions. */
#define configUSE_TIMERS                        1
#define configTIMER_TASK_PRIORITY               ( configMAX_PRIORITIES - 1 )
#define configTIMER_QUEUE_LENGTH                10
#define configTIMER_TASK_STACK_DEPTH            1024

/* Interrupt nesting behaviour configuration. */
/*
#define configKERNEL_INTERRUPT_PRIORITY         [dependent of processor]
#define configMAX_SYSCALL_INTERRUPT_PRIORITY    [dependent on processor and application]
#define configMAX_API_CALL_INTERRUPT_PRIORITY   [dependent on processor and application]
*/

/* SMP port only */
#define configNUM_CORES                         2
#define configTICK_CORE                         0
#define configRUN_MULTIPLE_PRIORITIES           1
#define configUSE_CORE_AFFINITY                 1

/* RP2040 specific */
#define configSUPPORT_PICO_SYNC_INTEROP         1
#define configSUPPORT_PICO_TIME_INTEROP         1

#include <assert.h>
/* Define to trap errors during development. */
#define configASSERT(x)                         assert(x)

/* Set the following definitions to 1 to include the API function, or zero
 to exclude the API function. */
#define INCLUDE_vTaskPrioritySet                1
#define INCLUDE_uxTaskPriorityGet               1
#define INCLUDE_vTaskDelete                     1
#define INCLUDE_vTaskSuspend                    1
#define INCLUDE_vTaskDelayUntil                 1
#define INCLUDE_vTaskDelay                      1
#define INCLUDE_xTaskGetSchedulerState          1
#define INCLUDE_xTaskGetCurrentTaskHandle       1
#define INCLUDE_uxTaskGetStackHighWaterMark     1
#define INCLUDE_xTaskGetIdleTaskHandle          1
#define INCLUDE_eTaskGetState                   1
#define INCLUDE_xTimerPendFunctionCall          1
#define INCLUDE_xTaskAbortDelay                 1
#define INCLUDE_xTaskGetHandle                  1
#define INCLUDE_xTaskResumeFromISR              1
#define INCLUDE_xQueueGetMutexHolder            1

/* A header file that defines trace macro can be included here. */

#endif /* FREERTOS_CONFIG_H */

3. Build

In the pico_freertos_smp directory, run:

$ mkdir build && cd build
$ cmake ..
$ make

After building, the .uf2, .bin, and .elf files will be generated in the build directory.

Once loaded onto the Pico board, the output will be:

task0 cnt: 0
task1 cnt: 0
task task1 is runing in core 1
task task0 is runing in core 0
task1 cnt: 1
task task1 is runing in core 1
task0 cnt: 1
task task0 is runing in core 0
task1 cnt: 2
task task1 is runing in core 1
task0 cnt: 2
task task0 is runing in core 0

Tags: RP2040 FreeRTOS SMP Pico embedded

Posted on Sat, 23 May 2026 22:31:14 +0000 by mrwutang

Freaks City

Creating a Custom Project for RP2040-SMP

1. Project Setup

2. Downloading FreeRTOS-SMP Source Code

Modifying the pico-smp Project

3. Build

Hot Tags