Creating a Board

The fastest way to create a new board is to modify an existing board with similar hardware configuration. In this example, we will create a new board based on the sf32lb52-lcd_n16r8 (i.e., sf32lb52-devkit-lcd) board. The new board uses the SF32LB525 chip and has an external NOR Flash, so starting with the sf32lb52-lcd_n16r8 board is a good choice.

The steps are as follows:

Create a folder testboard_525 under the boards directory and copy the files from sf32lb52-lcd_n16r8 to testboard_525.
Create a folder testboard_525_base under the boards directory and copy the files from sf32lb52-devkit-lcd to testboard_525_base.
Modify testboard_525/SConscript, changing the macro names in locations 1 and 2 to the new board’s name, and change the SConscript file path referenced in location 3 to testboard_525_base.

`

The modified code looks like this:

Modify the board macros in testboard_525/hcpu/Kconfig.board and testboard_525/lcpu/Kconfig.board to match the names from the previous step. The modified code is as follows:

hcpu/Kconfig.board

config BSP_USING_BOARD_TESTBOARD_525
    bool
    select SOC_SF32LB52X
    select BF0_HCPU
    default y

rsource "../Kconfig.board"

lcpu/Kconfig.board

config BSP_USING_BOARD_TESTBOARD_525
    bool
    select SOC_SF32LB52X
    select BF0_LCPU
    default y

rsource "../Kconfig.board"

Modify testboad_525/Kconfig.board to reference the Kconfig.board from testboard_525_base:
```
source "$SIFLI_SDK/customer/boards/testboard_525_base/Kconfig.board"
```

At this point, a new board has been created. You can switch to hello_world/rtt/project and run the following command to compile using the new board:

> scons --board=testboard_525 -j8
scons: Reading SConscript files ...
Board: testboard_525_hcpu
========
Multi-Project Info
--------
full_name       main.bootloader
parent          main
bsp_root        D:\code\release_v2.3\release_v2.3.0_test\example\boot_loader\project\butterflmicro\ram_v2
build_dir       build_testboard_525_hcpu/bootloader
link_script     D:/code/release_v2.3/release_v2.3.0_test/example/boot_loader/project/butterflmicro/ram_v2\link
ptab            D:/code/release_v2.3/release_v2.3.0_test/customer/boards/testboard_525\ptab.json
embedded:       False
--------
full_name       main
parent
bsp_root        D:\code\release_v2.3\release_v2.3.0_test\example\get-started\hello_world\rtt\project
build_dir       build_testboard_525_hcpu/
link_script     D:/code/release_v2.3/release_v2.3.0_test/drivers/cmsis/sf32lb52x/Templates/gcc/HCPU/link
ptab            D:/code/release_v2.3/release_v2.3.0_test/customer/boards/testboard_525\ptab.json
--------
full_name       main.ftab
parent          main
bsp_root        D:\code\release_v2.3\release_v2.3.0_test\example\flash_table\sf32lb52x_common_v2
build_dir       build_testboard_525_hcpu/ftab
link_script     D:/code/release_v2.3/release_v2.3.0_test/drivers/cmsis/sf32lb52x/Templates/gcc/HCPU/link
ptab            D:/code/release_v2.3/release_v2.3.0_test/customer/boards/testboard_525\ptab.json
embedded:       False
========

Board Directory Structure

The directory structure for the board is as follows:

testboard_525

|   Kconfig.board          // Board's Kconfig configuration file
|   ptab.json              // Memory partition table
|   SConscript             // Build script
|   
+---hcpu
|       board.conf         // HCPU minimum configuration file generated by menuconfig
|       custom_mem_map.h   // Used when CUSTOM_MEM_MAP is enabled, for custom memory mapping
|       Kconfig            
|       Kconfig.board      // HCPU's Kconfig configuration file, can source the parent directory's `Kconfig.board`
|       rtconfig.py        // Can specify JLINK_DEVICE, used when generating the download script
|       
\---lcpu    
        board.conf         // LCPU minimum configuration file generated by menuconfig
        custom_mem_map.h
        Kconfig
        Kconfig.board
        rtconfig.py

testboard_525_base

|   board.h
|   bsp_board.h
|   bsp_init.c        // Implementation of HAL_PreInit
|   bsp_lcd_tp.c      // IO-related configuration code
|   bsp_pinmux.c      // IO-related configuration code
|   bsp_power.c       // IO-related configuration code
|   Kconfig.board     // Board's Kconfig configuration file
|   
\---script
        SConscript

The testboard_525_base directory is separated to improve code reuse. A single board might have several variants (e.g., using different chips), and by referencing testboard_525_base, multiple boards can be created without duplicating modifications. If there are no variants for the board, the files in testboard_525_base can be merged directly into testboard_525 by adjusting the file references.

Modify Board Configuration

The board configuration includes several aspects:

Hardware connections are defined in files such as bsp_pinmux.c, board.conf, and Kconfig.board.
- board.conf stores options configurable via menuconfig, such as the serial port used for the console. To modify, run menuconfig in the directory where board.conf is located and press D to save the minimal configuration.
- Kconfig.board stores options not visible in menuconfig, such as pin assignments for touch interrupts, PWM device numbers for backlight, etc.
```
config ASIC
    bool 
    default y 

config TOUCH_IRQ_PIN
    int
    default 26

config LCD_PWM_BACKLIGHT_INTERFACE_NAME
    string
    default "pwm3"

config LCD_PWM_BACKLIGHT_CHANEL_NUM
    int
    default 4

config LCD_BACKLIGHT_CONTROL_PIN
    int
    default 1

config RGBLED_CONTROL_PIN
    int
    default 32  
```
- Files like bsp_pinmux.c configure pin functions and pull-up/down properties through functions such as BSP_PIN_Init and the HAL_PIN_Set interface.
Memory partition table (ptab.json): This file describes the memory partitioning information, including NOR Flash, NAND Flash, PSRAM, internal SRAM, SD cards, etc. During compilation, ptab.json generates a ptab.h file in the build directory, which defines macros like _START_ADDR, _OFFSET, and _SIZE for each partition. These macros can be used in the code to access partition information. For the partition table syntax, please refer to Partition Table.

For more information, refer to Common Project Build Method.