ROM requirement details

Hi !

I’ve read that the library requires 64KB program memory (Flash). I was wondering what it means exactly : is it the size of the compiled library with full options and modules ? Is it the avarage size needed ? Does it comprises the size of external elements such as images or fonts ?

thank you very much for your answer.


It means the minimum size with only the most essential features and a small font.
Where did you see 64 kB? My intention was to tell 80kB. Maybe I forget to update it somewhere.


Thank you for your answer !
What is the size of a small font according to you ?

I found it on littlevgl documentation/Requirements :

On this link, it is said to be 80KB

It previously mentioned 64KB on the README as well. I just updated it to say 80KB.

To be sure about the actual memory usage I’ve tested v6.0 on STM32F429 Discovery (240x320 display) and updated the docs accordingly.

The results:
Create only a label and a button without any extra features (animations, shadow, file system etc):

  • Flash: 45 kB
  • RAM: 8kB

Use lv_test_theme_1 and turn on everything:

  • Flash: 150kB
  • RAM: 12kB

LV_MEM_SIZE: with everything enabled 18 kB was required for lv_test_theme_1

Display buffer:

  • 1 line: works but very slow
  • 4 lines: usable
  • 10 lines: smooth
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Based on @kisvegabor’s results, I would summarize that, as of the v6.0 release:

  • 32KB of RAM is mandatory for LittlevGL itself, with possibly a little more for drivers/OS/application.
  • 64KB of Flash will give you just enough room to build a small GUI. For complex setups you may need 128KB.

I’d say 16 kB is enough with for LittlevGL with a very minimal UI.
8kB RAM for LittlevGL + 2 kB Stack + 4kB for the objects + 2kB for display buffer = 16kB.

Thank you for the update on

@kisvegabor No problem!

Thanks for your helpful answers ! =)