lvgl/docs/porting/timer-handler.md

Timer Handler

To handle the tasks of LVGL you need to call lv_timer_handler() periodically in one of the following:

• while(1) of main() function
• timer interrupt periodically (lower priority than lv_tick_inc())
• an OS task periodically

The timing is not critical but it should be about 5 milliseconds to keep the system responsive.

Example:

while(1) {
  lv_timer_handler();
  my_delay_ms(5);
}

If you want to use lv_timer_handler() in a super-loop, a helper functionlv_timer_handler_run_in_period() is provided to simplify the porting:

while(1) {
    ...
    lv_timer_handler_run_in_period(5); /* run lv_timer_handler() every 5ms */
    ...
}

In an OS environment, you can use it together with the delay or sleep provided by OS to release CPU whenever possible:

while (1) {
    lv_timer_handler_run_in_period(5); /* run lv_timer_handler() every 5ms */
    my_delay_ms(5);                    /* delay 5ms to avoid unnecessary polling */
}

To learn more about timers visit the Timer section.