SF32LB52x-DevKit-LCD example: adding an SPI-LCD (external)¶

1 Confirm that the rt-driver project runs normally¶

It is recommended to use the rt-driver project for screen debugging. Before debugging, confirm that the rt-driver project can run normally and print logs

1.1 Build¶

Enter the example\rt_driver\project directory, right-click and select ComEmu_Here to open a build command terminal, then execute the commands in sequence

> D:\sifli\git\sdk\v2.2.4\set_env.bat   #设置编译环境路径
> scons --board=sf32lb52-lcd_n16r8 -j8   #指定sf32lb52-lcd_n16r8模块编译rt-driver工程

alt text

1.2 Enter BOOT mode¶

Confirm that the sf32lb52-lcd_n16r8 module board enters boot mode for downloading. Operate as shown below
alt text

1.3 Download¶

> build_sf32lb52-lcd_n16r8\uart_download.bat

     Uart Download

please input the serial port num:7 #然后选择sf32lb52-lcd_n16r8模块连接的串口号进行下载 

1.4 Confirm normal logs¶

As shown below, to run the user program, uncheck the option to enter BOOT. After confirming that the board is running, you can proceed to the next step to add a new screen module.
alt text

2 Add the gc9107 screen driver¶

2.1 Create the gc9107 driver¶

Add the project and modify the Kconfig.proj file in the new screen driver folder sdk-demo
Copy SDK\example\rt_driver (if you already have an external project, you can modify and add directly in the project), rename it with the screen driver name multi_screen, and place it outside the SDK. Then modify the Konfig.proj file in project to add the following content

#APP specific configuration.

comment "------------Project configuration-----------"  

if !BSP_USING_BUILT_LCD
    ···
endif

Modify the proj.conf file

Add # CONFIG_BSP_USING_BUILTIN_LCD is not set to project\proj.conf to use an external screen driver and disable the SDK built-in screen driver.
If you want only a specific board to use an external screen driver, or to use the built-in screen driver, create a new file under the project directory, such as sf32lb52-lcd_n16r8/proj.conf, and add # CONFIG_BSP_USING_BUILTIN_LCD is not set or CONFIG_BSP_USING_BUILTIN_LCD=y to it

Copy the driver
The screen drivers in the SDK are located in sdk\customer\peripherals. Copy another driver with a spi interface into the newly created screen driver folder sdk-demo and rename it to qspi_gc9107

2.2 Add gc9107_Multi_screen in Menuconfig¶

Modify Kconfig to generate an option for this screen in menuconfig.
Open project\Kconfig.proj in a text editor and add the option and resolution for this spi screen, as follows

# menuconfig 生成菜单呈现的选项
    choice
        prompt "Custom LCD driver"
        default LCD_USING_TFT_ZJY085_MULTI_SCREEN
		
        config LCD_USING_TFT_ZJY085_MULTI_SCREEN
            bool "0.85 rect SPI LCD(0.85TFT-SPI)--Multi_screen"   #menuconfig中显示的字符
            select LCD_USING_GC9107_MULTI_SCREEN   #spi_gc9107文件夹内文件是否的编译依赖于此宏
            select BSP_LCDC_USING_SPI_DCX_1DATA    #选择SPI接口
	endchoice

    config LCD_HOR_RES_MAX  #为屏的水平分辨率 
        int
        default 384 if LCD_USING_TFT_ZJY085_MULTI_SCREEN

    config LCD_VER_RES_MAX  #为屏的垂直分辨率
        int
        default 256 if LCD_USING_TFT_ZJY085_MULTI_SCREEN

    config LCD_DPI     #像素密度，为屏一英寸多少个像素点，不知道就填默认315
        int
        default 214 if LCD_USING_TFT_ZJY085_MULTI_SCREEN

Add LCD_USING_GC9107_MULTI_SCREEN
Open the file project\Kconfig.proj in a text editor and add the following

if !BSP_USING_BUILT_LCD

	config LCD_USING_GC9107_MULTI_SCREEN  #添加该配置，Kconfig中才能select上
		bool
		default n

endif

alt text
3) Modify SConscript
Open the file gc9107_Multi_screen\SConscript in a text editor and modify the macro LCD_USING_GC9107_MULTI_SCREEN, so that the *.c and *.h files in this directory can be included in the build

2.3 Select gc9107_Multi_screen in Menuconfig¶

After completing the above steps, enter the following command in the build window and select the newly added gc9107_Multi_screen screen
menuconfig --board=sf32lb52-lcd_n16r8 (open the menuconfig window) Under this path (Top) →Custom LCD driver, select the newly added screen. An example is shown below. Save and exit, and the screen driver in the spi_gc9107_Multi_screen directory will be selected to participate in the build
alt text

3 Screen hardware connection¶

3.1 FFC connection¶

If you purchased a matching screen module, simply connect the ribbon cable to the connector, as shown below.
alt text

3.2 Fly-wire connection¶

If the FPC pin arrangement of the new screen module is inconsistent, you need to design an FPC adapter board yourself or debug using jumper wires from the pin headers.
For the adapter board design, refer to SF32LB52-DevKit-LCD Adapter Board Fabrication Guide

4 Screen driver configuration¶

4.1 Default IO configuration¶

If the default IO is used, you can skip this section

4.1.1 IO mode settings¶

The LCD uses the LCDC1 hardware to output waveforms and must be configured to the corresponding FUNC mode.
For the Funtion options available on each IO, refer to the hardware documentation Download SF32LB52X_Pin_config.
alt text
The RESET pins of both the LCD and TP use GPIO mode, so they are already configured as GPIO mode by default.

 HAL_PIN_Set(PAD_PA00, GPIO_A0,  PIN_NOPULL, 1);     // #LCD_RESETB
 HAL_PIN_Set(PAD_PA09, GPIO_A9,  PIN_NOPULL, 1);     // CTP_RESET

4.1.2 IO power-on/off operations¶

The following is the LCD initialization process after power-on:
rt_hw_lcd_ini->api_lcd_init->lcd_task->lcd_hw_open->BSP_LCD_PowerUp-find_right_driver->LCD_drv.LCD_Init->LCD_drv.LCD_ReadID->lcd_set_brightness->LCD_drv.LCD_DisplayOn
You can see that BSP_LCD_PowerUp after power-on occurs before display driver initialization LCD_drv.LCD_Init.
Therefore, before initializing the LCD, ensure that the LCD power supply has been enabled in BSP_LCD_PowerUp.
alt text

4.1.3 Backlight PWM configuration¶

There is a default configuration in the pwm software, configured in customer\boards\sf32lb52-lcd_n16r8\Kconfig.board. After compilation, this Kconfig.board configuration generates the following three macros in rtconfig.h

//PWM3需要打开GPTIM2，PWM和TIMER对应关系，可以查看FAQ的PWM部分或者文件`pwm_config.h`
#define LCD_PWM_BACKLIGHT_INTERFACE_NAME "pwm3" //pwm设备名
#define LCD_PWM_BACKLIGHT_CHANEL_NUM 4 //Channel 4
#define LCD_BACKLIGHT_CONTROL_PIN 1 //PA01

Using PWM3 requires GPTIM2 (located in Hcpu) for output. Also confirm whether the following macros in rtconfig.h take effect

#define BSP_USING_GPTIM2 1 //如果用PWM3，需要menuconfig --board=sf32lb52-lcd_n16r8打开
#define RT_USING_PWM 1
#define BSP_USING_PWM 1
#define BSP_USING_PWM3 1 //如果没有，需要menuconfig --board=sf32lb52-lcd_n16r8打开

The following shows the correspondence between pwm3 and GPTIM2 in pwm_config.h

#ifdef BSP_USING_PWM3
#define PWM3_CONFIG                             \
    {                                           \
       .tim_handle.Instance     = GPTIM2,         \
       .tim_handle.core         = PWM3_CORE,    \
       .name                    = "pwm3",       \
       .channel                 = 0             \
    }
#endif /* BSP_USING_PWM3 */

alt text
By default, the software outputs the PWM waveform on PA01 from the "pwm3" device of GPTIM2. The default configuration is in

HAL_PIN_Set(PAD_PA01, GPTIM2_CH4, PIN_NOPULL, 1);   // LCDC1_BL_PWM_CTRL, LCD backlight PWM

Note:
After configuration through the function HAL_PIN_Set, the mapping between GPTIM2_CH4 and PA01 is established. This is specifically reflected in the register configuration hwp_hpsys_cfg->GPTIM2_PINR, as shown below:
alt text
You can see that it can be configured as CH1-CH4 output, and it must be on ports PA00-PA44.

4.2 Screen driver reset timing¶

The following delays are critical. Modify them carefully according to the initialization timing in the relevant screen driver IC documentation.

    BSP_LCD_Reset(0);//Reset LCD
    HAL_Delay_us(20);
    BSP_LCD_Reset(1);

4.3 Screen driver register modification¶

The initialization register configuration varies significantly between screen driver ICs. Write to the screen driver IC through SPI in sequence according to the register parameters provided by the screen vendor and their SPI timing. Pay special attention to the required delay length after register 0x11

    LCD_WriteReg_More(hlcdc, 0x11, parameter, 1);
    LCD_DRIVER_DELAY_MS(120);

    LCD_WriteReg_More(hlcdc, 0xFE, parameter, 0); // internal reg enable
    LCD_WriteReg_More(hlcdc, 0xEF, parameter, 0); // internal reg enable

4.4 Screen driver parameter configuration¶

.lcd_itf: select LCDC_INTF_SPI_DCX_1DATA to indicate SPI 1-line mode
.freq: select 48000000, indicating that the SPI clk main frequency is 48 MHz. Choose this clock according to the maximum clock supported by the screen driver IC. A higher value shortens the data transfer time per frame and increases the frame rate
.color_mode: select RGB565 or RGB888 format
.syn_mode: select whether to enable the TE anti-tearing function. If TE is enabled but the screen driver IC has no TE signal, no data will be sent to the screen and a Timeout crash will occur. It is recommended to disable TE during early debugging
.vsyn_polarity: select the polarity of TE
.vsyn_delay_us: select how long after the TE waveform arrives LCDC1 starts sending data to the screen driver IC
.readback_from_Dx: select which D0-D3 signal line outputs data from the screen driver IC when QSPI reads the Chipid (refer to the screen driver IC manual)

static LCDC_InitTypeDef lcdc_int_cfg =
{
    .lcd_itf = LCDC_INTF_SPI_DCX_1DATA,
    .freq = 48000000,
    .color_mode = LCDC_PIXEL_FORMAT_RGB565,
    .cfg = {
        .spi = {

            .dummy_clock = 0,
            .syn_mode = HAL_LCDC_SYNC_DISABLE,
            .vsyn_polarity = 0,
            .vsyn_delay_us = 0,
            .hsyn_num = 0,
        },
    },

};

5 Build, program, download, and results¶

5.1 Display result¶

As shown below, if the display is normal, 6 images will be displayed in sequence, looping every 3 seconds.
alt text