docs(os) add example and clarify some poinits
@@ -16,6 +16,39 @@ If you need to use real tasks or threads, you need a mutex which should be invok
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.
+Here is some pseudocode to illustrate the concept:
+
+```c
+static mutex_t lvgl_mutex;
+
+void lvgl_thread(void)
+{
+ while(1) {
+ mutex_lock(&lvgl_mutex);
+ lv_task_handler();
+ mutex_unlock(&lvgl_mutex);
+ thread_sleep(10); /* sleep for 10 ms */
+ }
+}
+
+void other_thread(void)
+{
+ /* You must always hold the mutex while using LVGL APIs */
+ mutex_lock(&lvgl_mutex);
+ lv_obj_t *img = lv_img_create(lv_scr_act());
+ mutex_unlock(&lvgl_mutex);
+
+ while(1) {
+ mutex_lock(&lvgl_mutex);
+ /* change to the next image */
+ lv_img_set_src(img, next_image);
+ mutex_unlock(&lvgl_mutex);
+ thread_sleep(2000);
+ }
+}
+```
+
## Interrupts
Try to avoid calling LVGL functions from interrupt handlers (except `lv_tick_inc()` and `lv_disp_flush_ready()`). But if you need to do this you have to disable the interrupt which uses LVGL functions while `lv_timer_handler` is running.
-It's a better approach to set a flag or some value and periodically check it in an `lv_timer`.
+
+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 `lv_timer_handler`).
