{"id":3686,"date":"2018-02-16T11:35:32","date_gmt":"2018-02-16T19:35:32","guid":{"rendered":"https:\/\/visualgdb.com\/w\/?p=3686"},"modified":"2018-02-16T11:35:32","modified_gmt":"2018-02-16T19:35:32","slug":"using-freertos-with-nordic-nrf5x-devices","status":"publish","type":"post","link":"https:\/\/visualgdb.com\/tutorials\/arm\/nrf51\/freertos\/","title":{"rendered":"Using FreeRTOS-with Nordic nRF5x Devices"},"content":{"rendered":"

This tutorial shows how to use the FreeRTOS real-time\u00a0operating system with the Nordic nRF5x devices. We will show how to create a basic project using FreeRTOS, change its configuration, view\u00a0the real-time thread trace and understand the program\u00a0timings by using the embedded profiler. Before you begin, install VisualGDB 5.3 or later and get the latest\u00a0Nordic BSP via the VisualGDB Package Manager.<\/p>\n

    \n
  1. Start Visual Studio and open the VisualGDB Embedded Project Wizard:\"01-demo\"<\/a><\/li>\n
  2. On the first page of the wizard select “Create a new project with MSBuild” -> “Embedded Binary”:\"02-msbuild\"<\/a><\/li>\n
  3. On the next page select your ARM toolchain and pick\u00a0the Nordic device you are targeting. In this\u00a0tutorial we will target the nRF52840 device:\"03-nosoftdev\"<\/a>As the Nordic FreeRTOS sample does not include the necessary configuration parameters for the softdevice, select “Softdevice: None” before proceeding to the next page. You can still use FreeRTOS with softdevice-enabled projects, however you would need to ensure that they include both FreeRTOS and Softdevice configuration files.<\/li>\n
  4. On the next page select “Show basic samples” and pick the LEDBlink (FreeRTOS) sample and proceed with the default configuration:
    \n    \"04-board\"<\/a><\/li>\n
  5. Connect your\u00a0development board to\u00a0your computer. VisualGDB will automatically detect the best debug settings for the board. If you have multiple boards, or debug interfaces, select the matching one manually:\"05-debug\"<\/a><\/li>\n
  6. Press “Finish” to create the project. VisualGDB will create an MSBuild-based project based on the FreeRTOS sample. Build it by pressing Ctrl-Shift-B and start debugging by pressing F5:\"06-run\"<\/a><\/li>\n
  7. Now we will\u00a0use the RTOS analysis\u00a0functionality to understand how\u00a0the sample works. First of all,\u00a0set a breakpoint in the led_toggle_timer_callback() function and\u00a0open the Threads view once the breakpoint hits:
    \n    \"07-threads\"<\/a>VisualGDB will\u00a0show all\u00a0FreeRTOS threads (and their stacks) in the Threads view.<\/li>\n
  8. Now we will use the\u00a0VisualGDB profiler to see\u00a0which functions are called by each thread (RTOS thread view and profiling requires the Custom edition of VisualGDB). Select Analyze->Analyze Performance with VisualGDB:\"08-profile\"<\/a><\/li>\n
  9. VisualGDB\u00a0profiler works by inserting the profiler framework code into your project and instrumenting the functions in your code to report their timing. This doesn’t require any extra hardware, although results in an extra overhead while profiling.\u00a0\u00a0First time you select “Analyze Performance with VisualGDB”, it will suggest referencing the profiler framework and preparing the code for instrumentation. Select “Instrumentation” in the message box:\"09-instr\"<\/a><\/li>\n
  10. Once the\u00a0profiler framework is referenced, select “Instrument functions to record their time” and press OK:\"10-instr-run\"<\/a><\/li>\n
  11. VisualGDB will start a profiling session. Use the Live Profiling view to see the\u00a0functions that are being invoked at real time. See how most of the\u00a0the time is spent in the prvIdleTask:\"11-stats\"<\/a><\/li>\n
  12. Once you exit a profiling session, you can use the Profiling\u00a0Reports window to\u00a0list and open the\u00a0profiling reports from previous profiling sessions:\"12-report\"<\/a><\/li>\n
  13. Although profiling provides detailed view of your\u00a0program’s internals,\u00a0instrumenting\u00a0each and every function results in overhead.\u00a0An less intrusive way of analyzing your program’s\u00a0performance would be\u00a0using the real-time watch. Open VisualGDB Project Properties on the Dynamic Analysis page and enable RTOS event tracing and function tracing:
    \n    \"13-trace\"<\/a>Unlike the profiling mode, functions instrumented\u00a0for real-time watch will only report their actual run time to VisualGDB if you specifically\u00a0add them to the real-time watch window,\u00a0reducing the profiling overhead.<\/li>\n
  14. Before you begin\u00a0the real-time watch session, we recommend increasing the MAX_TASK_NAME_LEN parameter in the FreeRTOSConfig.h file to 8 so that the thread names won’t get truncated:\"14-task\"<\/a><\/li>\n
  15. Start debugging and\u00a0select “Debug->Break All” once the LEDs start blinking. Open real-time watch, select “RTOS threads” and resume debugging. VisualGDB will show the precise timing of all 3 threads and the computed CPU utilization:\"15-times\"<\/a><\/li>\n
  16. You can\u00a0use the mouse wheel to zoom the real-time watch window, and click-and-drag to measure distances between events:\"16-period\"<\/a><\/li>\n
  17. Real-time watch also allows\u00a0measuring run times of specific functions. Add the led_toggle_timer_callback()<\/strong> and bsp_board_led_invert<\/strong> functions to the real-time watch list and resume your program. VisualGDB will show\u00a0their riming. E.g. you can see that bsp_board_led_invert<\/strong> is called by both the timer thread and the LED0 thread:\"17-functions\"<\/a><\/li>\n
  18. Zoom into the invocation of bsp_board_led_event<\/strong> to\u00a0measure the time between different events (e.g. between switching to the Tmr Svc thread and actually invoking the function):\"18-overheads\"<\/a><\/li>\n
  19. You can add a reference to FreeRTOS for an existing project by using the Embedded Frameworks page of VisualGDB Project Properties:
    \n    \"19-freertos\"<\/a><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

    This tutorial shows how to use the FreeRTOS real-time\u00a0operating system with the Nordic nRF5x devices. We will show how to<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[18],"tags":[67,95],"_links":{"self":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts\/3686"}],"collection":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/comments?post=3686"}],"version-history":[{"count":1,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts\/3686\/revisions"}],"predecessor-version":[{"id":3706,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts\/3686\/revisions\/3706"}],"wp:attachment":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/media?parent=3686"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/categories?post=3686"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/tags?post=3686"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}