这里的示例以百问网的7寸（1024x600）、4寸方屏（480x480）、4寸圆屏RGB（480x480） LCD为例。
这里建议用百问网提供的 r128-devkit-100ask-rgb 方案，仓库地址:
初始化环境变量，选择方案(r128s2_devkit_100ask_rgb_c906与r128s2_devkit_100ask_rgb_m33)：
100ask@100ask:~/R128-FreeRTOS/SDK$ source envsetup.sh
Setup env done!
Run lunch_rtos to select project
100ask@100ask:~/R128-FreeRTOS/SDK$ lunch_rtos
last=r128s2_devkit_c906
You're building on Linux
Lunch menu... pick a combo:
1. r128s2_devkit_100ask_rgb_c906
2. r128s2_devkit_100ask_rgb_m33
3. r128s2_devkit_c906
4. r128s2_devkit_m33
5. r128s2_devkit_rgb_c906
6. r128s2_devkit_rgb_m33
7. r128s2_evt_c906
8. r128s2_evt_m33
Which would you like? [Default r128s2_devkit_c906]: 1
select=1...
r128s2/devkit_100ask_rgb_c906
'/home/100ask/R128-FreeRTOS/SDK/lichee/rtos/projects/r128s2/devkit_100ask_rgb_c906/defconfig' -> '/home/100ask/R128-FreeRTOS/SDK/lichee/rtos/.config'
============================================
RTOS_BUILD_TOP=/home/100ask/R128-FreeRTOS/SDK
RTOS_TARGET_ARCH=riscv
RTOS_TARGET_CHIP=sun20iw2p1
RTOS_TARGET_DEVICE=r128s2
RTOS_PROJECT_NAME=r128s2_devkit_100ask_rgb_c906
============================================
Run mrtos_menuconfig to config rtos
Run m or mrtos to build rtos
menuconfig具体配置：
# 1.打开下面的 Drivers
Drivers Options --->
soc related device drivers --->
PWM devices --->
[*] enable pwm driver
[ ] enable pwm hal APIs test command
TWI Devices --->
-*- enable twi driver
[ ] enable twi hal APIs test command
Video support for sunxi --->
[*] DISP Driver Support(sunxi-disp2)
......
# 2. 打开LVGL相关配置
System components --->
thirdparty components --->
[*] Littlevgl-8 --->
--- Littlevgl-8
[*] lvgl examples
[ ] lvgl g2d test
[*] lvgl-8.1.0 use sunxifb double buffer
[*] lvgl-8.1.0 use sunxifb cache
[ ] lvgl-8.1.0 use sunxifb g2d
[ ] lvgl-8.1.0 use sunxifb g2d rotate
[ ] lvgl-8.1.0 use freetype
[ ] lvgl-8.1.0 use direct mode
修改文件：R128-FreeRTOS/board/r128s2/devkit_rgb/configs/sys_config.fex
[lcd0]
lcd_used = 1
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;; 7寸屏（1024x600）
lcd_driver_name = "default_lcd"
lcd_backlight = 150
lcd_if = 0
lcd_x = 1024
lcd_y = 600
lcd_width = 150
lcd_height = 94
lcd_rb_swap = 0
lcd_dclk_freq = 48
lcd_pwm_used = 1
lcd_pwm_ch = 7
lcd_pwm_freq = 500000
lcd_pwm_pol = 1
lcd_hbp = 150
lcd_ht = 1344
lcd_hspw = 20
lcd_vbp = 20
lcd_vt = 635
lcd_vspw = 3
lcd_lvds_if = 0
lcd_lvds_colordepth = 1
lcd_lvds_mode = 0
lcd_frm = 0
lcd_io_phase = 0x0000
lcd_gamma_en = 0
lcd_bright_curve_en = 0
lcd_cmap_en = 0
;;;;;; 4寸方屏（480x480）
;lcd_driver_name = "default_lcd"
;lcd_backlight = 150
;lcd_if = 0
;lcd_x = 480
;lcd_y = 480
;lcd_width = 70
;lcd_height = 70
;lcd_rb_swap = 1
;lcd_dclk_freq = 9
;lcd_pwm_used = 1
;lcd_pwm_ch = 7
;lcd_pwm_freq = 500000
;lcd_pwm_pol = 1
;lcd_hbp = 20
;lcd_ht = 526
;lcd_hspw = 6
;lcd_vbp = 10
;lcd_vt = 510
;lcd_vspw = 4
;lcd_lvds_if = 0
;lcd_lvds_colordepth = 1
;lcd_lvds_mode = 0
;lcd_frm = 1
;lcd_io_phase = 0x0000
;lcd_gamma_en = 0
;lcd_bright_curve_en = 0
;lcd_cmap_en = 0
;;;;;; 4寸圆屏RGB（480*480）
;lcd_driver_name = "default_lcd"
;lcd_backlight = 200
;lcd_if = 0
;lcd_x = 480
;lcd_y = 480
;lcd_width = 70
;lcd_height = 70
;lcd_rb_swap = 1
;lcd_dclk_freq = 9
;lcd_pwm_used = 1
;lcd_pwm_ch = 7
;lcd_pwm_freq = 2000
;lcd_pwm_pol = 1
;lcd_hbp = 20
;lcd_ht = 526
;lcd_hspw = 6
;lcd_vbp = 10
;lcd_vt = 510
;lcd_vspw = 4
;lcd_lvds_if = 0
;lcd_lvds_colordepth = 1
;lcd_lvds_mode = 0
;lcd_frm = 1
;lcd_io_phase = 0x0000
;lcd_gamma_en = 0
;lcd_bright_curve_en = 0
;lcd_cmap_en = 0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
deu_mode = 0
lcdgamma4iep = 0
smart_color = 0
;LCD_D2-LCD_D7
lcd_gpio_0 = port:PA00<8><0><3><0>
lcd_gpio_1 = port:PA01<8><0><3><0>
lcd_gpio_2 = port:PA02<8><0><3><0>
lcd_gpio_3 = port:PA03<8><0><3><0>
lcd_gpio_4 = port:PA04<8><0><3><0>
lcd_gpio_5 = port:PA05<8><0><3><0>
;LCD_D10-LCD_D15
lcd_gpio_6 = port:PA11<8><0><3><0>
lcd_gpio_7 = port:PA10<8><0><3><0>
lcd_gpio_8 = port:PA08<8><0><3><0>
lcd_gpio_9 = port:PA07<8><0><3><0>
lcd_gpio_10 = port:PA06<8><0><3><0>
lcd_gpio_11 = port:PA09<8><0><3><0>
;LCD_D18-LCD_D23
lcd_gpio_12 = port:PA12<8><0><3><0>
lcd_gpio_13 = port:PA13<8><0><3><0>
lcd_gpio_14 = port:PA14<8><0><3><0>
lcd_gpio_15 = port:PA15<8><0><3><0>
lcd_gpio_16 = port:PB03<8><0><3><0>
lcd_gpio_17 = port:PB02<8><0><3><0>
;LCD_VSYNC, LCD_HSYNC, LCD_DCLK, LCD_DE
lcd_gpio_18 = port:PA18<8><0><3><0>
lcd_gpio_19 = port:PA19<8><0><3><0>
lcd_gpio_20 = port:PA20<8><0><3><0>
lcd_gpio_21 = port:PA21<8><0><3><0>
修改文件：SDK/lichee/rtos-components/thirdparty/littlevgl-8/lv_examples/src/lv_conf.h
/*Color depth: 1 (1 byte per pixel), 8 (RGB332), 16 (RGB565), 32 (ARGB8888)*/
#define LV_COLOR_DEPTH 32 /*这里可以改为16，因为de会自动转换到32位，最终显示还是32位色深*/
/*Swap the 2 bytes of RGB565 color. Useful if the display has an 8-bit interface (e.g. SPI)*/
#define LV_COLOR_16_SWAP 0
menuconfig具体配置：
Drivers Options --->
other drivers --->
[*] input driver --->
[*] keyboard driver --->
[*] touchscreen driver --->
[ ] enable tlsc6x touchscreen driver
[*] enable gt911 touchscreen driver
[ ] enable cst226se touchscreen driver
[ ] enable touchscreen drivers APIs test command
soc related device drivers --->
EFUSE Devices --->
[*] enable efuse driver
[ ] enable efuse hal APIs test command
修改文件：R128-FreeRTOS/board/r128s2/devkit_rgb/configs/sys_config.fex
[touchscreen]
tp_used = 1
tp_int = port:PA24<1><0><default><default>
tp_reset = port:PA25<1><0><default><default>
tp_revert_mode = 0
tp_exchange_flag = 0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;; 7寸屏（1024x600） GT911
tp_max_x = 1024
tp_max_y = 600
tp_addr = 0x14
;;;;;; 4寸方屏（480x480） GT911
;tp_max_x = 480
;tp_max_y = 480
;tp_addr = 0x14
;;;;;; 4寸圆屏RGB（480*480）
;待续...
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
tp_twi_id = 1
修改文件：SDK/lichee/rtos-components/thirdparty/littlevgl-8/lv_examples/src/lv_drv_conf.h
/*-------------------------------------------------
* Mouse or touchpad as evdev interface (for Linux based systems)
*------------------------------------------------*/
#ifndef USE_EVDEV
# define USE_EVDEV 1
#endif
以上配置完成后，编译打包烧录，上电后屏幕背光亮起，屏幕为黑色。
并且可以在 LOG 中看到 [LCD_FB] lcd_fb_probe,line:103: 和 spi_clk_init()1609 [spi1] clk rate auto adjust to 48000000 SPI 初始化的 LOG。
disp:[disp_device_attached_and_enable 230]attached ok, mgr0<-->dev0
disp:[disp_device_attached_and_enable 243]type:1,mode:0,fmt:rgb,bits:8bits,eotf:4,cs:0 dvi_hdmi:2, range:2 scan:0 ratio:8
[gt911][log] PRODUCT_ID=39:31:31:00:60:10
[gt911][log] verison=00 range_x=0 range_y=0 point_num=0
[gt911][log] PRODUCT_ID=39:31:31:00:60:10
[gt911][log] verison=42 range_x=480 range_y=480 point_num=5
通过执行 lv_examples 命令运行LVGL测试demo。
lv_examples 代码位于： SDK/lichee/rtos-components/thirdparty/littlevgl-8/lv_examples/src/lv_main.c