[中文]

Tick interface

LVGL needs a system tick to know the elapsed time for animations and other tasks.

There are two ways to provide the tick to LVGL:

1. Call lv_tick_set_cb(my_get_milliseconds_function);: my_get_milliseconds_function needs to tell how many milliseconds have elapsed since start up. Most of the platforms have built-in functions that can be used as they are. For example

   • SDL: lv_tick_set_cb(SDL_GetTicks);

   • Arduino: lv_tick_set_cb(millis);

   • FreeRTOS: lv_tick_set_cb(xTaskGetTickCount);

   • STM32: lv_tick_set_cb(HAL_GetTick);

   • ESP32: lv_tick_set_cb(my_tick_get_cb);, where my_tick_get_cb is a wrapper for esp_timer_get_time() / 1000;

2. Call lv_tick_inc(x) periodically, where x is the elapsed milliseconds since the last call. lv_tick_inc should be called from a high priority interrupt.

The ticks (milliseconds) should be independent from any other activities of the MCU.

For example this works, but LVGL's timing will be incorrect as the execution time of lv_timer_handler is not considered:

API

lv_tick.h