LVGL on Arduino Mega 2560

How-to
22

It wouldn’t bother if it didn’t run quickly and smoothly, as my application is very static anyway.

The text on the screenshots is partly in German. Here is the translation:

1.)
The sketch uses 12966 bytes (5%) of the program memory. The maximum is 253952 bytes.
Global variables use 233 bytes (2%) of dynamic memory, leaving 7959 bytes for local variables. The maximum is 8192 bytes.

2.)
The sketch uses 88122 bytes (34%) of the program memory. The maximum is 253952 bytes.
Global variables use 21851 bytes (266%) of dynamic memory, leaving -13659 bytes for local variables. The maximum is 8192 bytes.

UTFT_Size_Screenshot
UTFT_Size_Screenshot1920×1080 126 KB
UTFT_and_lvgl_Size_Screenshot
UTFT_and_lvgl_Size_Screenshot1920×1080 182 KB
lv_conf.h (24.7 KB)

The Code:

#include <lvgl.h>
#include <UTFT.h>

static lv_disp_buf_t disp_buf;
static lv_color_t buf[LV_HOR_RES_MAX * 10];

UTFT myGLCD(ITDB32S, 38, 39, 40, 41);
int x;
int y;

void timer_1(void)
{
  if (millis() % 5 > 1) //Every 5 ms
  {
    lv_tick_inc(1);
  }
}

void LCD_WritePixel(int x, int y, int color)
{
  myGLCD.setColor(color);
  myGLCD.drawPixel(x, y);
}


void setup()
{
  Serial.begin(9600);
  myGLCD.InitLCD();

  lv_disp_buf_init(&disp_buf, buf, NULL, LV_HOR_RES_MAX * 10);
  lv_disp_drv_t disp_drv;
  lv_disp_drv_init(&disp_drv);
  disp_drv.hor_res = 320;
  disp_drv.ver_res = 240;
  disp_drv.buffer = &disp_buf;
  disp_drv.flush_cb = my_flush_cb;
  lv_disp_t * disp;
  lv_disp_drv_register(&disp_drv); /*Register the driver and save the created display objects*/
}

void my_flush_cb(lv_disp_drv_t * disp_drv, const lv_area_t * area, lv_color_t * color_p)
{
  /*The most simple case (but also the slowest) to put all pixels to the screen one-by-one*/
  int32_t x, y;
  for (y = area->y1; y <= area->y2; y++) {
    for (x = area->x1; x <= area->x2; x++) {
      LCD_WritePixel(x,  y, color_p->full);
      color_p++;
    }
  }

  /* IMPORTANT!!!
     Inform the graphics library that you are ready with the flushing*/
  lv_disp_flush_ready(disp_drv);
}

void loop()
{
  timer_1();


  if (millis() % 5 > 1)
  {
    lv_task_handler();
  }
}

Best regards
David

23

Great (you don’t need to translate german language (mit mir kannst du auch deutsch sprechen, aber sehr langsam :slight_smile: ). So here are the changes I suggest:

  1. change static lv_color_t buf[LV_HOR_RES_MAX * 10]; to static lv_color_t buf[LV_HOR_RES_MAX * 1];
  2. in lv_conf.h change #define LV_ANTIALIAS 1 to #define LV_ANTIALIAS 0 and #define LV_MEM_CUSTOM 0 to #define LV_MEM_CUSTOM 1

Try co compile your sketch and post the result. If it still didn’t fit then you have to check if LVGL picks the right lv_conf.h file - there is no memory allocation for internal LVGL heap now…

24

That’s cool. Where are you from? Where do you come from? I’ve made the changes. You have created a change. But not enough.

Best regards
David

UTFT_and_lvgl_Size_New
UTFT_and_lvgl_Size_New1920×1080 174 KB

25

I’m from Czech Republic… Ok so there is change about 21851 - 15284 = 6567 bytes. Hmm, the last chance I see is to disable all widgets (LV_USE_BAR, LV_USE_BTNMATRIX, LV_USE_CHART, LV_USE_IMG, LV_USE_IMGBTN, LV_USE_SPINBOX). Maybe better way to check, what is so memory hungry is to check this project in Platformio and check the map file. Unfortunately I’m not able to give it a try this weekend :frowning:

26

Okay nice. That’s not a problem, it’s not urgent. I think it’s really cool how you try to help people. In addition to with, you can also learn a lot yourself. Thanks a lot for this!

Best regards
David