mirror of
https://github.com/lvgl/lvgl.git
synced 2025-01-28 07:03:00 +08:00
df0d36f02a
Signed-off-by: Josh Soref <2119212+jsoref@users.noreply.github.com> Co-authored-by: Gabor Kiss-Vamosi <kisvegabor@gmail.com>
76 lines
2.3 KiB
ReStructuredText
76 lines
2.3 KiB
ReStructuredText
.. _os_interrupt:
|
|
|
|
===============================
|
|
Operating system and interrupts
|
|
===============================
|
|
|
|
LVGL is **not thread-safe** by default.
|
|
|
|
However, in the following conditions it's valid to call LVGL related
|
|
functions:
|
|
|
|
- In *events*. Learn more in :ref:`events`.
|
|
- In *lv_timer*. Learn more in :ref:`timer`.
|
|
|
|
Tasks and threads
|
|
-----------------
|
|
|
|
If you need to use real tasks or threads, you need a mutex which should
|
|
be invoked before the call of :cpp:func:`lv_timer_handler` and released after
|
|
it. Also, you have to use the same mutex in other tasks and threads
|
|
around every LVGL (``lv_...``) related function call and code. This way
|
|
you can use LVGL in a real multitasking environment. Just make use of a
|
|
mutex to avoid the concurrent calling of LVGL functions.
|
|
|
|
LVGL has a built-in mutex which can be used with:
|
|
- :cpp:func:`lv_lock()` and :cpp:func:`lv_lock_isr()`
|
|
- :cpp:func:`lv_unlock()`
|
|
|
|
These functions are called internally in :cpp:func:`lv_timer_handler`
|
|
and the users need to call them only from their own threads.
|
|
|
|
To enable ``lv_lock/lv_unlock`` ``LV_USE_OS`` needs to be set to other
|
|
than ``LV_OS_NONE``.
|
|
|
|
|
|
Here is some pseudocode to illustrate the concept:
|
|
|
|
.. code:: c
|
|
|
|
void lvgl_thread(void)
|
|
{
|
|
while(1) {
|
|
uint32_t time_till_next;
|
|
time_till_next = lv_timer_handler(); /*lv_lock/lv_unlock is called internally*/
|
|
thread_sleep(time_till_next); /* sleep for a while */
|
|
}
|
|
}
|
|
|
|
void other_thread(void)
|
|
{
|
|
/* You must always hold the mutex while using LVGL APIs */
|
|
lv_lock();
|
|
lv_obj_t *img = lv_image_create(lv_screen_active());
|
|
lv_unlock();
|
|
|
|
while(1) {
|
|
lv_lock();
|
|
/* change to the next image */
|
|
lv_image_set_src(img, next_image);
|
|
lv_unlock();
|
|
thread_sleep(2000);
|
|
}
|
|
}
|
|
|
|
Interrupts
|
|
----------
|
|
|
|
Try to avoid calling LVGL functions from interrupt handlers (except
|
|
:cpp:func:`lv_tick_inc` and :cpp:func:`lv_display_flush_ready`). But if you need to do
|
|
this you have to disable the interrupt which uses LVGL functions while
|
|
:cpp:func:`lv_timer_handler` is running.
|
|
|
|
It's a better approach to simply set a flag or some value in the
|
|
interrupt, and periodically check it in an LVGL timer (which is run by
|
|
:cpp:func:`lv_timer_handler`).
|