From 796c8affdd0b16c5286ed8b01a4871736ae719c8 Mon Sep 17 00:00:00 2001
From: cyz <181662417@qq.com>
Date: Wed, 9 Jun 2021 12:35:52 +0800
Subject: [PATCH] =?UTF-8?q?rt=5Fhw=5Fus=5Fdelay=E7=9A=84=E5=AE=9E=E7=8E=B0?=
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---
 bsp/stm32/libraries/HAL_Drivers/drv_common.c | 32 +++++++++++++++-----
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/bsp/stm32/libraries/HAL_Drivers/drv_common.c b/bsp/stm32/libraries/HAL_Drivers/drv_common.c
index 74007b6e88..61171e7c8d 100644
--- a/bsp/stm32/libraries/HAL_Drivers/drv_common.c
+++ b/bsp/stm32/libraries/HAL_Drivers/drv_common.c
@@ -113,16 +113,32 @@ void _Error_Handler(char *s, int num)
  */
 void rt_hw_us_delay(rt_uint32_t us)
 {
-    rt_uint32_t start, now, delta, reload, us_tick;
-    start = SysTick->VAL;
-    reload = SysTick->LOAD;
-    us_tick = SystemCoreClock / 1000000UL;
-    do
+    rt_uint32_t ticks;
+    rt_uint32_t told, tnow, tcnt = 0;
+    rt_uint32_t reload = SysTick->LOAD;
+
+    ticks = us * reload / (1000000 / RT_TICK_PER_SECOND);
+    told = SysTick->VAL;
+    while (1)
     {
-        now = SysTick->VAL;
-        delta = start >= now ? start - now : reload + start - now;
+        tnow = SysTick->VAL;
+        if (tnow != told)
+        {
+            if (tnow < told)
+            {
+                tcnt += told - tnow;
+            }
+            else
+            {
+                tcnt += reload - tnow + told;
+            }
+            told = tnow;
+            if (tcnt >= ticks)
+            {
+                break;
+            }
+        }
     }
-    while (delta < us_tick * us);
 }
 
 /**