Copyright (C)2019-2025 VadRov / www.youtube.com/@VadRov / www.dzen.ru/vadrov

An example of integrating a display driver for stm32f4x (spi, dma) series microcontrollers into the popular LVGL library.

• For stm32f411ceu6 (blackpill board) MCU. Displays supported are st7789 and ili9341 (with and none CS).
• LVGL version 9.3.

PA2 -> DC, PA3 -> RES, PA4 -> CS, PA5 -> SCK, PA6 -> BLK, PA7 -> SDI

See display driver: https://github.com/vadrov/stm32-display-spi-dma

Define display options in main.c file:

#define	ILI9341	0		//do not edit!!!
#define ST7789	1		//do not edit!!!

/* user options */
#define ACTIVE_DISPLAY	ILI9341 //select active display driver
#define DISP_HOR_RES	320     //select display resolution
#define DISP_VER_RES	240

Initialize the display driver and LVGL in main.c:

#include "main.h"
#include "display.h"
#if ACTIVE_DISPLAY == ILI9341
#include "ili9341.h"
#elif ACTIVE_DISPLAY == ST7789
#include "st7789.h"
#endif
#include <stdlib.h>
#include "../../lvgl/lvgl.h"
#include "ui.h"

#define BYTES_PER_PIXEL (LV_COLOR_FORMAT_GET_SIZE(LV_COLOR_FORMAT_RGB565))

static uint8_t buf1[DISP_HOR_RES * 10 * BYTES_PER_PIXEL]; //double buffer for 10 lines
static uint8_t buf2[DISP_HOR_RES * 10 * BYTES_PER_PIXEL];

volatile uint32_t millis = 0; //ms system counter (increases in SysTick interrupt)

//display render callback
void my_flush_cb(lv_display_t *display, const lv_area_t *area, uint8_t *px_map)
{
    int w = area->x2 - area->x1 + 1;
    int h = area->y2 - area->y1 + 1;
    LCD_DrawImage(LCD, area->x1, area->y1, w, h, (uint16_t*)px_map, 1);
    lv_display_flush_ready(display);
}

//system counter callback
static uint32_t my_tick_cb(void)
{
    return millis;
}

int main(void)
{
    ...
    LCD_DMA_TypeDef dma_tx = { DMA2, 2 };
    LCD_BackLight_data bkl_data = { TIM3,
                                    TIM_CCER_CC1E,
                                    0,
                                    0,
                                    90  };
    LCD_SPI_Connected_data spi_con = { SPI1,
                                       dma_tx,
                                       LCD_RES_GPIO_Port,
                                       LCD_RES_Pin,
                                       LCD_DC_GPIO_Port,
                                       LCD_DC_Pin,
                                       LCD_CS_GPIO_Port,
                                       LCD_CS_Pin };

    LCD = LCD_DisplayAdd(LCD,
                         DISP_HOR_RES,
                         DISP_VER_RES,
#if ACTIVE_DISPLAY == ILI9341
                         ILI9341_CONTROLLER_WIDTH,
                         ILI9341_CONTROLLER_HEIGHT,
#elif ACTIVE_DISPLAY == ST7789
                         ST7789_CONTROLLER_WIDTH,
                         ST7789_CONTROLLER_HEIGHT,
#endif
                         0,
                         0,
                         PAGE_ORIENTATION_LANDSCAPE,
#if ACTIVE_DISPLAY == ILI9341
                         ILI9341_Init,
                         ILI9341_SetWindow,
                         ILI9341_SleepIn,
                         ILI9341_SleepOut,
#elif ACTIVE_DISPLAY == ST7789
                         ST7789_Init,
                         ST7789_SetWindow,
                         ST7789_SleepIn,
                         ST7789_SleepOut,
#endif
                         &spi_con,
                         LCD_DATA_16BIT_BUS,
                         bkl_data );
    LCD_Init(LCD);
    lv_init();
    lv_tick_set_cb(my_tick_cb);
    lv_display_t * display1 = lv_display_create(DISP_HOR_RES, DISP_VER_RES);
    lv_display_set_buffers(display1, buf1, buf2, DISP_HOR_RES * 10 * BYTES_PER_PIXEL, LV_DISPLAY_RENDER_MODE_PARTIAL);
    lv_display_set_flush_cb(display1, my_flush_cb);
    ui_init();
    while (1) { //infinity loop
        lv_timer_handler();
        LCD_DelayMs(1);
    }
}

ui_init() is a procedure that creates LVGL objects, their animations and interactions with them (events). See "ui" folder. The interface can be prepared, for example, in SquareLine Studio.

In the project properties, define the LV_LVGL_H_INCLUDE_SIMPLE symbol (Project -> Properties -> C/C++ Build -> Settings -> MCU GCC Compiler -> Preprocessor -> Define symbols (-D) Add... LV_LVGL_H_INCLUDE_SIMPLE):

The display image generated by this example:

Author: VadRov
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