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https://github.com/lvgl/lvgl.git
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153 lines
3.4 KiB
C
153 lines
3.4 KiB
C
/**
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* @file systick.c
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* Provide access to the system tick with 1 millisecond resolution
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*/
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/*********************
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* INCLUDES
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*********************/
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#include <lvgl/lv_hal/lv_hal_tick.h>
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#include <stddef.h>
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/*********************
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* DEFINES
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*********************/
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#define LV_HAL_TICK_CALLBACK_NUM 32
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/**********************
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* TYPEDEFS
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**********************/
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/**********************
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* STATIC PROTOTYPES
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**********************/
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/**********************
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* STATIC VARIABLES
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**********************/
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static uint32_t sys_time = 0;
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static volatile uint8_t tick_irq_flag;
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static volatile uint8_t tick_cb_sem; /*Semaphore for tick callbacks*/
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static void (*tick_callbacks[LV_HAL_TICK_CALLBACK_NUM])(void);
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/**********************
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* MACROS
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**********************/
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/**********************
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* GLOBAL FUNCTIONS
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**********************/
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/**
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* Call this function in every milliseconds
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*/
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void lv_tick_handler(void)
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{
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sys_time++;
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/*Run the callback functions*/
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uint8_t i;
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for (i = 0; i < LV_HAL_TICK_CALLBACK_NUM; i++) {
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if (tick_callbacks[i] != NULL) {
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tick_callbacks[i]();
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}
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}
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tick_irq_flag = 0; /*lv_hal_systick_get set it to know there was an IRQ*/
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}
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/**
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* Get the elapsed milliseconds since start up
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* @return the elapsed milliseconds
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*/
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uint32_t lv_tick_get(void)
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{
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uint32_t result;
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do {
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tick_irq_flag = 1;
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result = sys_time;
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} while(!tick_irq_flag); /*Systick IRQ clears this flag. Continue until make a non interrupted cycle */
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return result;
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}
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/**
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* Get the elapsed milliseconds science a previous time stamp
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* @param prev_tick a previous time stamp ( return value of systick_get() )
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* @return the elapsed milliseconds since 'prev_tick'
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*/
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uint32_t lv_tick_elaps(uint32_t prev_tick)
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{
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uint32_t act_time = lv_tick_get();
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/*If there is no overflow in sys_time simple subtract*/
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if(act_time >= prev_tick) {
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prev_tick = act_time - prev_tick;
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} else {
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prev_tick = UINT32_MAX - prev_tick + 1;
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prev_tick += act_time;
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}
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return prev_tick;
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}
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/**
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* Add a callback function to the systick interrupt
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* @param cb a function pointer
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* @return true: 'cb' added to the systick callbacks, false: 'cb' not added
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*/
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bool lv_tick_add_callback(void (*cb) (void))
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{
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bool suc = false;
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/*Take the semaphore. Be sure it is set*/
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do {
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tick_cb_sem = 1;
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} while(!tick_cb_sem);
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uint8_t i;
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for (i = 0; i < LV_HAL_TICK_CALLBACK_NUM; i++) {
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if (tick_callbacks[i] == NULL) {
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tick_callbacks[i] = cb;
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suc = true;
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break;
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}
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}
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/*Release the semaphore. Be sure it is cleared*/
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do {
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tick_cb_sem = 0;
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} while(tick_cb_sem);
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return suc;
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}
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/**
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* Remove a callback function from the tick callbacks
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* @param cb a function pointer (added with 'lv_hal_tick_add_callback')
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*/
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void lv_tick_rem_callback(void (*cb) (void))
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{
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/*Take the semaphore. Be sure it is set*/
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do {
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tick_cb_sem = 1;
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} while(!tick_cb_sem);
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uint8_t i;
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for (i = 0; i < LV_HAL_TICK_CALLBACK_NUM; i++) {
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if (tick_callbacks[i] == cb) {
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tick_callbacks[i] = NULL;
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break;
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}
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}
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/*Release the semaphore. Be sure it is cleared*/
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do {
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tick_cb_sem = 0;
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} while(tick_cb_sem);
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}
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/**********************
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* STATIC FUNCTIONS
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**********************/
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