[Bsp][stm32f4xx-hal]修复I2C在开启优化时出现延时异常的问题

lymzzyh · lymzzyh · commit ffdd7f98adf7 · 2018-10-11T16:47:25.000+08:00
diff --git 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 =

Original file line number	Diff line number	Diff line change
`@@ -78,11 +78,12 @@ static rt_int32_t drv_get_scl(void *data)`
`78`	`78`
`79`	`79`	`static void drv_udelay(rt_uint32_t us)`
`80`	`80`	`{`
`81`		`- int i = (HAL_RCC_GetHCLKFreq() / 4000000 * us);`
`82`		`- while (i)`
	`81`	`+ __IO uint32_t Delay = us * (SystemCoreClock / 8U / 1000000U);`
	`82`	`+ do`
`83`	`83`	`{`
`84`		`- i--;`
`85`		`- }`
	`84`	`+ __NOP();`
	`85`	`+ }`
	`86`	`+ while (Delay --);`
`86`	`87`	`}`
`87`	`88`
`88`	`89`	`static const struct rt_i2c_bit_ops drv_bit_ops =`