{"id":1348,"date":"2016-02-25T04:12:27","date_gmt":"2016-02-25T12:12:27","guid":{"rendered":"http:\/\/visualgdb.com\/w\/?p=1348"},"modified":"2016-02-25T04:12:27","modified_gmt":"2016-02-25T12:12:27","slug":"developing-mbed-applications-with-rtx-and-visual-studio","status":"publish","type":"post","link":"https:\/\/visualgdb.com\/tutorials\/arm\/mbed\/rtx\/","title":{"rendered":"Developing mbed applications with RTX and Visual Studio"},"content":{"rendered":"

This tutorial shows how to use the Keil RTX<\/a> real-time operating system to create multi-threaded embedded applications with mbed<\/a> and VisualGDB. Before you begin, install VisualGDB 5.1 or later and update your embedded tools via Embedded Tool Manager.<\/p>\n

    \n
  1. Start Visual Studio and begin creating a new project with the VisualGDB Embedded Project Wizard:\"01-rtxdemo\"<\/a><\/li>\n
  2. On the first page select “Create a new project” and ensure that the “Enable multi-threaded build” checkbox is checked:\"02-newbin\"<\/a><\/li>\n
  3. Click “Use ARM mbed” and select your mbed board in the device list. In this tutorial we will use the STM32F4Discovery board (DISCO_F407VG). Ensure you have newlib-nano selected as the C library:\"03-device\"<\/a><\/li>\n
  4. On the sample selection page select “LEDBlink (RTOS)” to create a project with RTOS support:\"04-rtos\"<\/a><\/li>\n
  5. On the Debug Settings page select your debug method. If you are using Segger J-Link or a device that can be programmed with firmware from segger, use the J-Link debug method, otherwise use OpenOCD:\"05-debug\"<\/a><\/li>\n
  6. Press “Finish” to generate your project. Build it via Build->Build Solution:\"06-build\"<\/a><\/li>\n
  7. Start debugging by pressing F5. See how the 2 LEDs blink with different periods as 2 independent threads are controlling them. Set a breakpoint on the line modifying the value of g_LED1 and wait for it to trigger:\"07-breakpoint\"<\/a><\/li>\n
  8. The line gets the current state of the LED, inverts it and sets the new state. Step into the operator that sets the new state by selecting Step Into Specific -> operator=(int):\"08-stepin\"<\/a><\/li>\n
  9. Step into the write() method function and\u00a0 into the gpio_write() function again to see what exactly happens when the new value is assigned to g_LED1:\"09-write\"<\/a><\/li>\n
  10. Now we will modify our source code to demonstrate communication between the 2 threads. Replace the contents of your main file with this:\n
    #include <mbed.h>\r\n#include <rtos.h>\r\n\u00a0\r\nDigitalOut g_LED1(LED1);\r\nDigitalOut g_LED2(LED2);\r\nSemaphore g_Semaphore(0);\r\n\r\nstatic void ThreadBody(const void *) \r\n{\r\n\u00a0\u00a0 \u00a0for (;;)\r\n\u00a0\u00a0 \u00a0{\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0g_LED1 = 0;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0g_Semaphore.wait();\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0g_LED1 = 1;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0Thread::wait(100);\r\n\u00a0\u00a0 \u00a0}\r\n}\r\n\r\nint main()\r\n{\r\n\u00a0\u00a0 \u00a0Thread thread(ThreadBody);\r\n\u00a0\u00a0 \u00a0for (;;)\r\n\u00a0\u00a0 \u00a0{\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0g_LED2 = !g_LED2;\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0g_Semaphore.release();\r\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0Thread::wait(300);\r\n\u00a0\u00a0 \u00a0}\r\n}<\/pre>\n
    This will create a global semaphore that will be signaled each time the main thread inverts the second LED. The background thread will wait for the signal and do a short pulse on the first LED when it receives it.<\/li>\n
  11. Build and run your program:\"10-run\"<\/a>Observe how the first LED pulses quickly each time the second one changes state.<\/li>\n
  12. You can step into the RTOS methods (e.g. Semaphore::wait()) by pressing F11. As your project includes all necessary mbed code, you can easily step through it and even modify it: \"11-sema\"<\/a><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"
    This tutorial shows how to use the Keil RTX real-time operating system to create multi-threaded embedded applications with mbed and<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[114],"tags":[56,115,61],"_links":{"self":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts\/1348"}],"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=1348"}],"version-history":[{"count":2,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts\/1348\/revisions"}],"predecessor-version":[{"id":1364,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts\/1348\/revisions\/1364"}],"wp:attachment":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/media?parent=1348"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/categories?post=1348"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/tags?post=1348"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}