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32 lines
940 B
Markdown
32 lines
940 B
Markdown
2 years ago
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# Tick interface
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LVGL needs a system tick to know elapsed time for animations and other tasks.
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You need to call the `lv_tick_inc(tick_period)` function periodically and provide the call period in milliseconds. For example, `lv_tick_inc(1)` when calling every millisecond.
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`lv_tick_inc` should be called in a higher priority routine than `lv_task_handler()` (e.g. in an interrupt) to precisely know the elapsed milliseconds even if the execution of `lv_task_handler` takes more time.
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With FreeRTOS `lv_tick_inc` can be called in `vApplicationTickHook`.
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On Linux based operating systems (e.g. on Raspberry Pi) `lv_tick_inc` can be called in a thread like below:
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```c
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void * tick_thread (void *args)
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{
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while(1) {
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usleep(5*1000); /*Sleep for 5 millisecond*/
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lv_tick_inc(5); /*Tell LVGL that 5 milliseconds were elapsed*/
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}
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}
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```
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## API
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```eval_rst
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.. doxygenfile:: lv_hal_tick.h
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:project: lvgl
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```
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