29 lines
722 B
C
29 lines
722 B
C
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/*
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* Copyright (c) 2006-2023, RT-Thread Development Team
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Change Logs:
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* Date Author Notes
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* 2023-06-14 muaxiaohei first version
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*/
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#include <rtthread.h>
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#include "drv_common.h"
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void rt_hw_us_delay(rt_uint32_t us)
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{
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uint64_t total_delay_ticks, us_ticks, start, now, delta, reload;
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start = SysTick->CNT;
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reload = SysTick->CMP;
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us_ticks = SystemCoreClock / 8000000UL;
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total_delay_ticks = (uint32_t)us * us_ticks;
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RT_ASSERT(total_delay_ticks < reload);
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do{
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now = SysTick->CNT;
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delta = start > now ? start - now : reload + start - now;
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}while(delta < total_delay_ticks);
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}
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