Creating an Application

The fastest way to create an application is to copy an existing example. Below, we will explain how to create a new application based on the hello_world example.

Copy the Example

1. Copy the example: Copy the example/get-started/hello_world/rtt directory to any desired location, such as c:\work\ws\hello_world.

   

   The directory structure of the application:

   +---project                // Project directory
   |       Kconfig
   |       Kconfig.proj
   |       proj.conf          // Project configuration file
   |       rtconfig.py
   |       SConscript
   |       SConstruct         
   |       
   \---src                    // Source code directory
           main.c
           SConscript
   

2. Open the Env command line window: Right-click on the SDK root directory and open the Env command line window, then run set_env gcc to set the environment parameters.

3. Change to the project directory: cd c:\work\ws\hello_world\project to switch to the copied example project directory.

4. Compile: scons --board=sf32lb52-lcd_n16r8 -j8. The selected board is sf32lb52-lcd_n16r8, refer to supported_boards/index.md.

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5. Flash: build_sf32lb52-lcd_n16r8_hcpu\uart_download.

At this point, a new hello_world program has been created, and the compilation and flashing methods for the new project are identical to those of the SDK’s built-in examples.

Modify the Code

The application code for hello_world is in the src/main.c file, where you can see that it prints “Hello world” only once on line 5.

int main(void)
{
    rt_thread_mdelay(3000);      
    /* Output a message on console using printf function */
    rt_kprintf("Hello world!\n");

    /* Infinite loop */
    while (1)
    {
    }
    return 0;
}

Now, add the following two lines between lines 10 and 11 to print “Hello SiFli” every 3 seconds.

int main(void)
{
    rt_thread_mdelay(3000);         
    /* Output a message on console using printf function */
    rt_kprintf("Hello world!\n");

    /* Infinite loop */
    while (1)
    {
        rt_kprintf("Hello SiFli!\n");
        rt_thread_mdelay(3000);  
    }
    return 0;
}

After modifying the code, compile and download the program. Connect the serial port debugging tool, reset the device, and you will see the printed output as shown in the image.

In addition to adding code in main.c, you can also add C files in the src directory. Since the SConscript in the src directory already uses the Glob command to include all C files in the current directory for compilation, you can simply add your new C files. For more details on using Scons scripts, refer to SCons.md.

import os
from building import *

# Add source code
src = Glob('*.c')
group = DefineGroup('Applications', src, depend = [''])

Return('group')

Modify Settings

The hello_world example only has basic print functionality, and many components are not enabled. Even if you include the headers for these components in main.c, their corresponding functions cannot be called unless you modify the project configuration using the menuconfig tool.

To modify the configuration, run menuconfig --board=<board_name> in the project directory. Replace <board_name> with the name of the board you are using, such as menuconfig --board=sf32lb52-lcd_n16r8. This is similar to specifying the board during scons compilation. By default, hcpu is used, meaning that menuconfig --board=sf32lb52-lcd_n16r8 and menuconfig --board=sf32lb52-lcd_n16r8_hcpu will have the same effect, both configuring the current project for the sf32lb52-lcd_n16r8 board’s HCPU.

After executing menuconfig, a screen like the following will appear. You can use the ⇧ and ⇩ arrow keys to navigate between menu items, press Enter to enter submenus, and press Space to select menu items. Once all changes are complete, press D to save the minimal configuration to the proj.conf file in the project directory (project\proj.conf). This file is a text file and can be opened to view the differences before and after modifications. For detailed usage of menuconfig, refer to menuconfig.md.

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For more detailed information on configuration and compilation mechanisms, please read build_and_configuration.md.