Problems with Initialising LVGL

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1

I am trying to include LVGL into ESP-IDF v5.3.1.
I keep getting errors related to ‘lv_disp_draw_buf_t’, and im not too sure what to do.
Here is my code if anyone can help me get started with it.

#include "lvgl.h"
#include "esp_lcd_panel_io.h"
#include "esp_lcd_panel_ops.h"
#include "esp_lcd_panel_vendor.h"
#include "driver/spi_master.h"

#define PIN_NUM_MOSI 13
#define PIN_NUM_CLK  14
#define PIN_NUM_CS   15
#define PIN_NUM_DC   2
#define PIN_NUM_RST  -1
#define PIN_NUM_BL   21

esp_lcd_panel_handle_t panel_handle = NULL; // Global variable

void lvgl_init_display(void) {
    static lv_disp_draw_buf_t draw_buf;
    static lv_color_t buf1[240 * 10]; // Buffer for 10 rows
    lv_disp_draw_buf_init(&draw_buf, buf1, NULL, 240 * 10);

    spi_bus_config_t buscfg = {
        .sclk_io_num = PIN_NUM_CLK,
        .mosi_io_num = PIN_NUM_MOSI,
        .miso_io_num = -1,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
        .max_transfer_sz = 240 * 320 * 2 + 8
    };
    spi_bus_initialize(SPI2_HOST, &buscfg, SPI_DMA_CH_AUTO);

    esp_lcd_panel_io_handle_t io_handle = NULL;
    esp_lcd_panel_io_spi_config_t io_config = {
        .dc_gpio_num = PIN_NUM_DC,
        .cs_gpio_num = PIN_NUM_CS,
        .pclk_hz = 20 * 1000 * 1000,
        .spi_mode = 0,
        .trans_queue_depth = 10,
        .lcd_cmd_bits = 8,
        .lcd_param_bits = 8
    };
    esp_lcd_new_panel_io_spi(SPI2_HOST, &io_config, &io_handle);

    esp_lcd_panel_dev_config_t panel_config = {
        .reset_gpio_num = PIN_NUM_RST,
        .color_space = ESP_LCD_COLOR_SPACE_RGB,
        .bits_per_pixel = 16
    };
    esp_lcd_new_panel_st7789(io_handle, &panel_config, &panel_handle);

    esp_lcd_panel_reset(panel_handle);
    esp_lcd_panel_init(panel_handle);
    esp_lcd_panel_disp_on_off(panel_handle, true);

    lv_disp_drv_t disp_drv;
    lv_disp_drv_init(&disp_drv);
    disp_drv.hor_res = 240;
    disp_drv.ver_res = 320;
    disp_drv.flush_cb = lvgl_flush_cb;
    disp_drv.draw_buf = &draw_buf;
    lv_disp_drv_register(&disp_drv);
}

void lvgl_flush_cb(lv_disp_drv_t *disp_drv, const lv_area_t *area, lv_color_t *color_p) {
    esp_lcd_panel_draw_bitmap(panel_handle, area->x1, area->y1, area->x2 + 1, area->y2 + 1, color_p);
    lv_disp_flush_ready(disp_drv);
}

void app_main(void) {
    lv_init();
    lvgl_init_display();

    lv_obj_t *label = lv_label_create(lv_scr_act());
    lv_label_set_text(label, "Hello, LVGL!");
    lv_obj_align(label, LV_ALIGN_CENTER, 0, 0);

    while (1) {
        lv_timer_handler();
        vTaskDelay(pdMS_TO_TICKS(10));
    }
}

Screenshot of errors

image
image993×385 32.3 KB

2

The code you shared is LVGL v8, it seems the library version you included is v9. There has been changes in the API. You might need to modify you implementation as below

void lvgl_init_display(void) {
    static uint8_t lvBuffer[240 * 10]; // Buffer for 10 rows

    spi_bus_config_t buscfg = {
        .sclk_io_num = PIN_NUM_CLK,
        .mosi_io_num = PIN_NUM_MOSI,
        .miso_io_num = -1,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
        .max_transfer_sz = 240 * 320 * 2 + 8
    };
    spi_bus_initialize(SPI2_HOST, &buscfg, SPI_DMA_CH_AUTO);

    esp_lcd_panel_io_handle_t io_handle = NULL;
    esp_lcd_panel_io_spi_config_t io_config = {
        .dc_gpio_num = PIN_NUM_DC,
        .cs_gpio_num = PIN_NUM_CS,
        .pclk_hz = 20 * 1000 * 1000,
        .spi_mode = 0,
        .trans_queue_depth = 10,
        .lcd_cmd_bits = 8,
        .lcd_param_bits = 8
    };
    esp_lcd_new_panel_io_spi(SPI2_HOST, &io_config, &io_handle);

    esp_lcd_panel_dev_config_t panel_config = {
        .reset_gpio_num = PIN_NUM_RST,
        .color_space = ESP_LCD_COLOR_SPACE_RGB,
        .bits_per_pixel = 16
    };
    esp_lcd_new_panel_st7789(io_handle, &panel_config, &panel_handle);

    esp_lcd_panel_reset(panel_handle);
    esp_lcd_panel_init(panel_handle);
    esp_lcd_panel_disp_on_off(panel_handle, true);

    static lv_display_t * lvDisplay = lv_display_create(240, 320)
    // lv_display_set_color_format(lvDisplay, LV_COLOR_FORMAT_RGB565);
    lv_display_set_flush_cb(lvDisplay, lvgl_flush_cb);
    lv_display_set_buffers(lvDisplay, lvBuffer, NULL, 240 * 10, LV_DISPLAY_RENDER_MODE_PARTIAL);
}

void lvgl_flush_cb(lv_display_t * disp, const lv_area_t * area, uint8_t * px_map) {
    esp_lcd_panel_draw_bitmap(panel_handle, area->x1, area->y1, area->x2 + 1, area->y2 + 1, px_map);
    lv_disp_flush_ready(disp);
}
3

Hi, This seemed to be better.

I made the following changes, this builds and flashes. But the display is blank.

#include "lvgl.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_lcd_panel_io.h"
#include "esp_lcd_panel_ops.h"
#include "esp_lcd_panel_vendor.h"
#include "driver/spi_master.h"

#define PIN_NUM_MOSI 13
#define PIN_NUM_CLK  14
#define PIN_NUM_CS   15
#define PIN_NUM_DC   2
#define PIN_NUM_RST  -1
#define PIN_NUM_BL   21 // Optional: Backlight control

esp_lcd_panel_handle_t panel_handle = NULL; // Global variable for the display panel

void lvgl_flush_cb(lv_display_t * disp, const lv_area_t * area, uint8_t * px_map) {
    esp_lcd_panel_draw_bitmap(panel_handle, area->x1, area->y1, area->x2 + 1, area->y2 + 1, px_map);
    lv_disp_flush_ready(disp);
}

void lvgl_init_display(void) {
    static uint8_t lvBuffer[240 * 10]; // Buffer for 10 rows

    // Initialize SPI bus
    spi_bus_config_t buscfg = {
        .sclk_io_num = PIN_NUM_CLK,
        .mosi_io_num = PIN_NUM_MOSI,
        .miso_io_num = -1,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
        .max_transfer_sz = 240 * 320 * 2 + 8
    };
    spi_bus_initialize(SPI2_HOST, &buscfg, SPI_DMA_CH_AUTO);

    // Initialize panel IO
    esp_lcd_panel_io_handle_t io_handle = NULL;
    esp_lcd_panel_io_spi_config_t io_config = {
        .dc_gpio_num = PIN_NUM_DC,
        .cs_gpio_num = PIN_NUM_CS,
        .pclk_hz = 20 * 1000 * 1000,
        .spi_mode = 0,
        .trans_queue_depth = 10,
        .lcd_cmd_bits = 8,
        .lcd_param_bits = 8
    };
    esp_lcd_new_panel_io_spi(SPI2_HOST, &io_config, &io_handle);

    // Initialize the display panel
    esp_lcd_panel_dev_config_t panel_config = {
        .reset_gpio_num = PIN_NUM_RST,
        .color_space = ESP_LCD_COLOR_SPACE_RGB,
        .bits_per_pixel = 16
    };
    esp_lcd_new_panel_st7789(io_handle, &panel_config, &panel_handle);

    // Reset and initialize the panel
    esp_lcd_panel_reset(panel_handle);
    esp_lcd_panel_init(panel_handle);
    esp_lcd_panel_disp_on_off(panel_handle, true);

    // Create LVGL display
    lv_display_t *lvDisplay = lv_display_create(240, 320); // Initialize dynamically
    lv_display_set_flush_cb(lvDisplay, lvgl_flush_cb);
    lv_display_set_buffers(lvDisplay, lvBuffer, NULL, 240 * 10, LV_DISPLAY_RENDER_MODE_PARTIAL);
}


void app_main(void) {
    // Initialize LVGL
    lv_init();

    // Initialize the display
    lvgl_init_display();

    // Create a basic LVGL label
    lv_obj_t *label = lv_label_create(lv_scr_act());
    lv_label_set_text(label, "Hello, LVGL!");
    lv_obj_align(label, LV_ALIGN_CENTER, 0, 0);

    // Main loop
    while (1) {
        lv_timer_handler(); // Process LVGL tasks
        vTaskDelay(pdMS_TO_TICKS(10));
    }
}
4

You’re probably missing the tick source, below is the relevant code. You would need to replace millis() with a similar function for esp idf

void app_main(void) {
    lv_init();
    lvgl_init_display();

    lv_obj_t *label = lv_label_create(lv_scr_act());
    lv_label_set_text(label, "Hello, LVGL!");
    lv_obj_align(label, LV_ALIGN_CENTER, 0, 0);

    static uint32_t lastTick = millis(); // get number milliseconds that has passed

    while (1) {
        uint32_t current = millis();
        lv_tick_inc(current - lastTick); // Update the tick timer. Tick is new for LVGL 9
        lastTick = current;
        lv_timer_handler();
        vTaskDelay(pdMS_TO_TICKS(10));
    }
}
5

Hi, i managed to get something displaying on the screen.
It says Hello, LVGL!. but the text does not look right, i usually see it landscape also. You cant see much on the photo, but the hello is messy like the LVGL! part.

image
image527×658 43.5 KB

#include "lvgl.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_lcd_panel_io.h"
#include "esp_lcd_panel_ops.h"
#include "esp_lcd_panel_vendor.h"
#include "driver/spi_master.h"
#include "driver/gpio.h"

#define PIN_NUM_MOSI 13
#define PIN_NUM_CLK  14
#define PIN_NUM_CS   15
#define PIN_NUM_DC   2
#define PIN_NUM_RST  -1
#define PIN_NUM_BL   21 // Backlight control pin

esp_lcd_panel_handle_t panel_handle = NULL; // Global panel handle

void lvgl_flush_cb(lv_display_t *disp, const lv_area_t *area, uint8_t *px_map) {
    esp_lcd_panel_draw_bitmap(panel_handle, area->x1, area->y1, area->x2 + 1, area->y2 + 1, px_map);
    lv_disp_flush_ready(disp);
}

void lvgl_init_display(void) {
    static uint8_t lvBuffer[240 * 10]; // Buffer for 10 rows

    // Initialize the SPI bus
    spi_bus_config_t buscfg = {
        .sclk_io_num = PIN_NUM_CLK,
        .mosi_io_num = PIN_NUM_MOSI,
        .miso_io_num = -1,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
        .max_transfer_sz = 240 * 320 * 2 + 8
    };
    spi_bus_initialize(SPI2_HOST, &buscfg, SPI_DMA_CH_AUTO);

    // Initialize panel IO
    esp_lcd_panel_io_handle_t io_handle = NULL;
    esp_lcd_panel_io_spi_config_t io_config = {
        .dc_gpio_num = PIN_NUM_DC,
        .cs_gpio_num = PIN_NUM_CS,
        .pclk_hz = 40 * 1000 * 1000, // Use 40 MHz for stability
        .spi_mode = 0,
        .trans_queue_depth = 10,
        .lcd_cmd_bits = 8,
        .lcd_param_bits = 8
    };
    esp_lcd_new_panel_io_spi(SPI2_HOST, &io_config, &io_handle);

    // Initialize the display panel
    esp_lcd_panel_dev_config_t panel_config = {
        .reset_gpio_num = PIN_NUM_RST,
        .color_space = ESP_LCD_COLOR_SPACE_BGR, // Use BGR color space
        .bits_per_pixel = 16
    };
    esp_lcd_new_panel_st7789(io_handle, &panel_config, &panel_handle);

    // Reset and initialize the panel
    esp_lcd_panel_reset(panel_handle);
    esp_lcd_panel_init(panel_handle);
    esp_lcd_panel_disp_on_off(panel_handle, true);
    esp_lcd_panel_invert_color(panel_handle, false); // Disable color inversion

    // Initialize backlight
    gpio_reset_pin(PIN_NUM_BL);
    gpio_set_direction(PIN_NUM_BL, GPIO_MODE_OUTPUT);
    gpio_set_level(PIN_NUM_BL, 1); // Turn on backlight

    // Create LVGL display
    lv_display_t *lvDisplay = lv_display_create(240, 320);
    lv_display_set_color_format(lvDisplay, LV_COLOR_FORMAT_RGB565); // Use RGB565
    lv_display_set_flush_cb(lvDisplay, lvgl_flush_cb);
    lv_display_set_buffers(lvDisplay, lvBuffer, NULL, 240 * 10, LV_DISPLAY_RENDER_MODE_PARTIAL);
}