Region RAM overflowed with simple Hello World test in Arduino


I am trying to get a “Hello World” app running on a smart watch based on atc1441/ATCwatch: Custom Arduino C++ firmware for the P8 and PineTime plus many more DaFit Smartwatches (, which is using an older version of lvgl which was customized.

What MCU/Processor/Board and compiler are you using?

I’m using Arduino and a DaFit Watch Bootloader 23 board, which I pulled out of the Arduino portable ljunquera/arduino-smartwatch-boards: D6 Fitness Tracker Arduino Core for Nordic Semiconductor nRF5 based boards (

What do you want to achieve?

Printing Hello World to the watch screen.

What have you tried so far?

Very simple compile of the code below with snippits taken from lvgl/LVGL_Arduino.ino at master · lvgl/lvgl (

Code to reproduce

void setup() {
  // put your setup code here, to run once:

and …

void display_label() {
    String LVGL_Arduino = "Hello Arduino! ";
    LVGL_Arduino += String('V') + lv_version_major() + "." + lv_version_minor() + "." + lv_version_patch();
      /* Create simple label */
    lv_obj_t *label = lv_label_create( lv_scr_act() );
    lv_label_set_text( label, LVGL_Arduino.c_str() );
    lv_obj_align( label, LV_ALIGN_CENTER, 0, 0 );

Screenshot and/or video

/Users/[yyy]/Library/Arduino15/packages/nRF52D6Fitness/tools/gcc-arm-none-eabi/5_2-2015q4/bin/../lib/gcc/arm-none-eabi/5.2.1/../../../../arm-none-eabi/bin/ld: region RAM overflowed with stack
collect2: error: ld returned 1 exit status
Using library lvgl at version 8.3.4 in folder: /Users/[yyy]/Documents/Arduino/libraries/lvgl 
exit status 1
Error compiling for board DaFit Watch Bootloader 23.

Found the answer here:
Region RAM overflowed with simple Hello World test in Arduino - Get started - LVGL Forum