NXP IMXRT1020 + FreeRTOS + LWIP

Overview

This example shows how to build an HTTP server using Mongoose Library and run it on an NXP i.MX RT1020 development board with FreeRTOS and lwIP.

The source code for this tutorial is located at https://github.com/mongoose-examples/nxp-mimxrt1020-freertos

Project structure

A big part of this example is a regular MCUXpresso IDE project (a lot of generated files, FreeRTOS and lwIP sources, etc.). Mongoose-related functions are located in files source/web_server.c and source/web_server.h. Mongoose itself is located in the source directory as well. Board network configuration (e.g. IP address) can be found in source/web_server.h

General description

Below is a general process outline:

First of all, set IP address, network mask and gateway suitable for your network in the source/web_server.h file. Default address is 192.168.0.10.
Build the example and run it on your development board (see next section).
The firmware initializes the network
After initialization, the application starts Mongoose's event loop and blinks an LED
Once the LED starts blinking - the web server is ready
Open your web browser and navigate to the board IP address, you should see a "Hello, world" page

Build options

There are (at least) two options to build the example:

Using the make command
Using the MCUXpresso IDE software

Option 1 - make

Install Docker
Start a terminal, navigate to the project folder, and from there run
```
$ make build
```
When build finishes, flash the board using your favorite tool

Done! See the LEDs to understand the application status

Option 2 - MCUXpresso IDE

MCUXpresso IDE is an IDE software provided by NXP Semiconductor. To build this sample with MCUXpresso IDE you need to do the following steps:

Start MCUXpresso IDE
Choose File -> Open Projects from File System...
Pick the project directory as Import source, make sure that nxp-mimxrt1020-freertos is checked, and click Finish
Check if you have the required SDK installed, if not:
- Press Install New Plugin SDKs
- In the board list choose evkmimxrt1020 and press Install
- Once the wizard has finished, you should see the SDK has been installed
Choose Debug As -> MCUXpresso IDE LinkServer, to build and flash the application
You can be asked to choose the board to use
After a successful building and flashing, the execution will pause at the beginning of the main function, choose Run -> Resume to continue.
Switch to the Console tab to see the example output
Once the LED starts to blink - navigate to the board address to see the "Hello, world!" page

Custom application

In order to create your own Mongoose-enabled application you have several ways:

The obvious way, is to add the required functionality to this example. The sample includes all standard HAL Drivers. As you can see in the source/web_server.c file, a HAL function is used to turn on an LED. In the same way, you can have access to all the HAL functions.
If, for some reason, you can't use this example as a base (e.g.: you have your own big project to which you need to add Mongoose), you can do the following:
- First of all, if your project uses Redlib consider switching to Newlib (or NewlibNano) - Redlib lacks some functions and Mongoose functionality can be limited.
- If your project uses NewLib - enable float usage for printf (Properties->C/C++ Build->Settings->MCU Settings->Enable print float)
- Add FreeRTOS and lwIP to your project and write (or copy from this example) initialization code
- Add the mongoose.c (and .h if you want) file(s) to your project
- Add Mongoose-specific configuration flags
- Add the following defines in the lwipopts.h file:
```
#define LWIP_SOCKET                     1
#define LWIP_POSIX_SOCKETS_IO_NAMES     0
#define SO_REUSE                        0
```
- Add MG_ARCH=MG_ARCH_FREERTOS_LWIP to the preprocessor symbols (Properties->C/C++ Build->Settings->Preprocessor)
- Done! Now write code similar to that in source/web_server.c (read Mongoose documentation) and let the magic begin

Modify SDK example

If you want to evaluate STM and Mongoose as fast and simple as possible, but you have a board that is not covered by any of our examples and tutorials, try to use the lwip_tcp_echo_freertos example: it supports a lot of boards. example

Copy the example to your workspace, choose Newlib while importing
Add mongoose.c and web_server.c to your project
Add the same Mongoose-specific configuration flags as described at the Build your own application section
Comment out the tcpecho_init(); line in the stack_init function and call mg_run_server() instead
That's it! Your application should build and run Mongoose.