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@@ -66,3 +66,16 @@ void rt_hw_board_init(void)
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#endif
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#endif
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}
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}
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+void rt_hw_us_delay(rt_uint32_t us)
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+{
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+ rt_uint32_t start, now, delta, reload, us_tick;
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+ start = SysTick->VAL;
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+ reload = SysTick->LOAD;
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+ us_tick = SystemCoreClock / 1000000UL;
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+ do
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+ {
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+ now = SysTick->VAL;
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+ delta = start >= now ? start - now : reload + start - now;
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+ }
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+ while (delta < us_tick * us);
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+}
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