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/**
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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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#ifdef LV_CONF_INCLUDE_SIMPLE
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#include "lv_conf.h"
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#else
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#include "../../lv_conf.h"
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#endif
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#include "lv_hal_tick.h"
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#include <stddef.h>
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#if LV_TICK_CUSTOM == 1
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#include LV_TICK_CUSTOM_INCLUDE
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#endif
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/*********************
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 *      DEFINES
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 *********************/
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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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/**********************
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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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 * You have to call this function periodically
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 * @param tick_period the call period of this function in milliseconds
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 */
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LV_ATTRIBUTE_TICK_INC void lv_tick_inc(uint32_t tick_period)
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{
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    tick_irq_flag = 0;
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    sys_time += tick_period;
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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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#if LV_TICK_CUSTOM == 0
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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);     /*'lv_tick_inc()' clears this flag which can be in an interrupt. Continue until make a non interrupted cycle */
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    return result;
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#else
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    return LV_TICK_CUSTOM_SYS_TIME_EXPR;
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#endif
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}
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/**
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 * Get the elapsed milliseconds since 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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 *   STATIC FUNCTIONS
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 **********************/
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