Creating a basic HTTP server with STM32F7-Discovery

This tutorial shows how to create a very basic HTTP server project with the STM32F7-Discovery board using the lwIP library and VisualGDB. Before you begin, install Visual Studio and VisualGDB 5.1 or later.

1. Start Visual Studio and open the VisualGDB Embedded Project Wizard:
2. Proceed with the default “new embedded binary” setting:
3. On the next page of the wizard select the ARM toolchain and choose the STM32F746NG device used on the STM32F7-Discovery board. If you are using a different board, you would need to copy the hardware setup functions from the examples for that board (more details in the end of this tutorial).
4. On the Sample Selection page choose the “HTTP Server” example and press “Next”:
5. Finally select a debug method that works with your board. For most STM32 boards you can simply select OpenOCD and plug the board in to get the settings auto-detected:
6. Press “Finish” to generate your project. Build it with Ctrl-Shift-B:
7. Ensure the on-board ST-Link is connected to your computer and that the Ethernet port is connected to a network with a valid DHCP server:
8. Start debugging by pressing F5. Observe how the board reports the IP address it gets via the semihosting window:
9. Open your browser and go to the address of the board:
10. Set a breakpoint after the call to the netconn_recv() and refresh the page in your browser. Hover the mouse over the inbuf variable to find out the address of the payload buffer:
11. Copy the payload buffer address to the Memory window to see the contents of the request received from the browser:
12. Now we will quickly go through the components used by the server example. The project relies on the STM32 HAL library, FreeRTOS library for multi-threading support and the lwIP library for the network functionality. You can add and remove references to these frameworks via VisualGDB Project Properties: You can configure various settings of those frameworks by editing stm32f7xx_hal_conf.h, FreeRTOSConfig.h and lwipopts.h.
13. The central point of the application is the MainThread() function. It calls the netconn API functions such as netconn_accept() that are similar to the normal socket functions. You can use the Code Map provided by the Clang IntelliSense to quickly visualize the relations between the functions:
14. If you want to target a different board, you need to replace the SystemClock_Config() function in the main file and the entire ethernetif.c file with the ones from an Ethernet example for your board. Note that ethernetif.c files from non-RTOS examples are not compatible with the RTOS-based examples.