From ffdd7f98adf778f7fdfe46bf48d2845de4f559f4 Mon Sep 17 00:00:00 2001
From: ZYH <lymz@foxmail.com>
Date: Thu, 11 Oct 2018 16:47:25 +0800
Subject: [Bsp][stm32f4xx-hal]修复I2C在开启优化时出现延时异常的问题
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---
 bsp/stm32f4xx-HAL/drivers/drv_i2c.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/bsp/stm32f4xx-HAL/drivers/drv_i2c.c b/bsp/stm32f4xx-HAL/drivers/drv_i2c.c
index f1e4ca5a5f..4cc04ae292 100644
--- a/bsp/stm32f4xx-HAL/drivers/drv_i2c.c
+++ b/bsp/stm32f4xx-HAL/drivers/drv_i2c.c
@@ -78,11 +78,12 @@ static rt_int32_t  drv_get_scl(void *data)
 
 static void drv_udelay(rt_uint32_t us)
 {
-    int i = (HAL_RCC_GetHCLKFreq() / 4000000 * us);
-    while (i)
+    __IO uint32_t Delay = us * (SystemCoreClock / 8U / 1000000U);
+    do 
     {
-        i--;
-    }
+        __NOP();
+    } 
+    while (Delay --);
 }
 
 static const struct rt_i2c_bit_ops drv_bit_ops =
-- 
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