ESP32-4827S043N testing label updating issue

[phpo1-61]

Owing to this site, I was able to run some of the get started examples available in lvgl 9.4 site.

Informations about low-level drivers for Sunton Cheap Yellow displays as mine: ESP32-4827S043N and lv_conf.h considerations have been very useful to start with lvgl matter (which seems to be very rich). My lv_conf.h file corresponds with the V9.3.0 lvgl version and I only modified the #0 in #1 at the top of file in order to enable the file to be included.
Now i intend to cutomize my first configuration which consists in updating a label with a lv_label_set_text_fmt command inserte in loop().
Up to now, the label display (lv_label_display_test function within setup(up) section) is correctly executed, whereas the lv_label_set_text_fmt command located in loop() seems to stop run time (the following Serial.print is not executed).

My work environment is:

VSCode:

Version: 1.103.0
Commit: e3550cfac4b63ca4eafca7b601f0d2885817fd1f
Date: 2025-08-06T21:40:10.271Z
Electron: 37.2.3
ElectronBuildId: 12035395
Chromium: 138.0.7204.100
Node.js: 22.17.0
V8: 13.8.500258-electron.0
OS: Linux x64 6.15.9-201.fc42.x86_64

platformIO version:

$ pio system info

*****************************************************************************
Obsolete PIO Core v6.1.17 is used (previous was 6.1.18)
Please remove multiple PIO Cores from a system:
https://docs.platformio.org/en/latest/core/installation/troubleshooting.html
--------------------------  --------------------------------------------------
PlatformIO Core             6.1.17
Python                      3.13.5-final.0
System Type                 linux_x86_64
Platform                    Linux-6.15.9-201.fc42.x86_64-x86_64-with-glibc2.41
File System Encoding        utf-8
Locale Encoding             UTF-8
PlatformIO Core Directory   /home/admin/.platformio
PlatformIO Core Executable  /usr/bin/platformio
Python Executable           /usr/bin/python3
Global Libraries            0
Development Platforms       3
Tools & Toolchains          15



I use the Arduino platform within PLatformIO, not ESP-IDF.

Here is my PlatformIO.ini file:

; PlatformIO Project Configuration File
;
;   Build options: build flags, source filterlv_label_dispay_test
;   Upload options: custom upload port, speed and extra flags
;   Library options: dependencies, extra library storages
;   Advanced options: extra scripting
;
; Please visit documentation for the other options and examples
; https://docs.platformio.org/page/projectconf.html

[env:esp32-4827S043N]
platform = espressif32
board = esp32-4827S043N
framework = arduino

monitor_speed = 115200
monitor_rts = 0
monitor_dtr = 0
monitor_filters = esp32_exception_decoder

build_flags =
	-Ofast
	-Wall
	'-D LV_CONF_PATH="${platformio.include_dir}/lv_conf.h"'
	'-D CORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_VERBOSE'
	'-D ESP_LCD_PANEL_IO_ADDITIONS_VER_MAJOR=1'
	'-D ESP_LCD_PANEL_IO_ADDITIONS_VER_MINOR=0'
	'-D ESP_LCD_PANEL_IO_ADDITIONS_VER_PATCH=1'


lib_deps =
    rzeldent/esp32_smartdisplay@^2.1.1
    ${platformio.include_dir}

and main.cpp:

#include <Arduino.h>
#include <esp32_smartdisplay.h>
#include "../.pio/libdeps/esp32-4827S043N/lvgl/examples/lv_examples.h"

float cnt = 1.00;
lv_obj_t * label;

// callback function (tick management)
// elapsedtime since startup
static uint32_t my_tick_get_cb(void) { return millis(); }


void update_display()
{
    lv_label_set_text_fmt(label, "counter: %f ", cnt);
}


void lv_label_dispay_test(void)
{
    lv_obj_t * obj1;
    obj1 = lv_obj_create(lv_screen_active());
    lv_obj_set_size(obj1, 100, 100);
    lv_obj_align(obj1, LV_ALIGN_CENTER, -30, 0);
    lv_obj_t * label = lv_label_create(obj1);
    lv_label_set_text(label, "counter");
}

void setup()
{
smartdisplay_init();
    lv_init();
    lv_tick_set_cb(my_tick_get_cb); // Set the tick callback function

  auto display = lv_display_get_default(); //
  // lv_display_set_rotation(display, LV_DISPLAY_ROTATION_90);
  // lv_display_set_rotation(display, LV_DISPLAY_ROTATION_180);
  // lv_display_set_rotation(display, LV_DISPLAY_ROTATION_270);
  smartdisplay_lcd_set_backlight(0.5);
// 0 pas de retroeclairage
// 0.5 50%
// 1 eclairage 100%

lv_label_dispay_test();
}

void loop()
{

    // Update the UI
    lv_timer_handler();
    update_display();
    Serial.print("counter: ");
    Serial.println(cnt);
    cnt=cnt+1;
    delay(2000);
}

I don't know how to investigate with this issue and would appreciate any advice about it.

Kind regards.

Philippe.

[phpo1-61]

A reminder of the features on my ESP32-4827S043N card:

ESP32 S3 WROOM1
ST7262 driver (16 bits parallel interface)
RGB 16 bits depth

A careful reading of the lvgl9.3 documentation indicates the following steps for configuring the lvgl display :

**- create a lvgl object: **(to be located in the setup() section of main.cpp)

lv_display_t * display1 = lv_display_create(480,270); // 480x270: my screen resolution

- declare an associated draw buffer: (to be located in the setup() section of main.cpp)

// Declare buffer for 1/10 screen size; BYTES_PER_PIXEL will be 2 for RGB565.
#define BYTES_PER_PIXEL (LV_COLOR_FORMAT_GET_SIZE(LV_COLOR_FORMAT_RGB565))
static uint8_t buf1[480 * 270 / 10 * BYTES_PER_PIXEL]; // 480x270 resolution
// Set display buffer for display `display1`.
lv_display_set_buffers(display1, buf1, NULL, sizeof(buf1), LV_DISPLAY_RENDER_MODE_PARTIAL);

- declare an associated flush callback function

void my_flush_cb(lv_display_t * display, const lv_area_t * area, uint8_t * px_map)
{
    /* The most simple case (also the slowest) to send all rendered pixels to the
     * screen one-by-one.  `put_px` is just an example.  It needs to be implemented by you. */
    uint16_t * buf16 = (uint16_t *)px_map; /* Let's say it's a 16 bit (RGB565) display */
    int32_t x, y;
    for(y = area->y1; y <= area->y2; y++) {
        for(x = area->x1; x <= area->x2; x++) {
            put_px(x, y, *buf16);
            buf16++;
        }
    }

    /* IMPORTANT!!!
     * Inform LVGL that flushing is complete so buffer can be modified again. */
    lv_display_flush_ready(display);
}

So far, I am unable to implement the commands related to the generic 'put_px' function mentionned above.

However, from several cases on the lvgl forum, I think I understood that I need to use some commands of an intermediate library, for example lovyan03/LovyanGFX which seems to suit with my equipment.

LovyanGFX/examples/Advanced/LVGL_PlatformIO/src/main.cpp gives an example for implemention of flush callback, but for lvgl8.3.4.

/* Display flushing */
void my_disp_flush( lv_disp_drv_t *disp, const lv_area_t *area, lv_color_t *color_p )
{
    if (gfx.getStartCount() == 0)
    {   // Processing if not yet started
        gfx.startWrite();
    }
    gfx.pushImageDMA( area->x1
                    , area->y1
                    , area->x2 - area->x1 + 1
                    , area->y2 - area->y1 + 1
                    , ( lgfx::swap565_t* )&color_p->full);
    lv_disp_flush_ready( disp );
}

I would like to know if i am taking the right steps in order to meet my need and if so, if someone can help me with the coding of my_flush_cb functin in lvgl 9.3.