From 0bce1acabd6e77aaa6a770d30e2f24f153639da4 Mon Sep 17 00:00:00 2001
From: EN <none>
Date: Fri, 12 Jul 2024 23:00:46 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BF=AE=E6=94=B9=E8=B6=85=E5=A3=B0=E6=B3=A2?=
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---
 Core/Inc/hcsr04.h |  3 +--
 Core/Src/hcsr04.c | 54 ++++++++++++-----------------------------------
 2 files changed, 15 insertions(+), 42 deletions(-)

diff --git a/Core/Inc/hcsr04.h b/Core/Inc/hcsr04.h
index 9c00c39..e890867 100644
--- a/Core/Inc/hcsr04.h
+++ b/Core/Inc/hcsr04.h
@@ -3,7 +3,6 @@
 
 #include "main.h"
 
-int16_t sonar_mm(void);
-float sonar(void);
+uint16_t sonar(void);
 
 #endif
diff --git a/Core/Src/hcsr04.c b/Core/Src/hcsr04.c
index 95a164e..3cca771 100644
--- a/Core/Src/hcsr04.c
+++ b/Core/Src/hcsr04.c
@@ -1,54 +1,28 @@
 #include "hcsr04.h"
 #include "tim.h"
 
-// time 的单位是 μs
-static uint64_t time;     // 声明变量，用来计时
-static uint64_t time_end; // 声明变量，存储回波信号时间
-static uint8_t state = 1;
+// time 的单位是 1μs
+static volatile uint64_t time; // 声明变量，用来计时
+static uint64_t time_end;      // 声明变量，存储回波信号时间
+static uint8_t state = 0;
 
 // HACK 临时的 delay 解决方法
 void delay_us(uint16_t us);
 
-int16_t sonar_mm(void) // 测距并返回单位为毫米的距离结果
+uint16_t sonar(void) // 测距并返回单位为毫米的距离结果
 {
-    uint32_t distance, distance_mm = 0;
+    // 超时则返回5m距离
+    uint32_t distance = 5000;
     HAL_GPIO_WritePin(SCL_C_GPIO_Port, SCL_C_Pin, GPIO_PIN_SET);   // 输出高电平
     delay_us(15);                                                  // 延时15微秒
     HAL_GPIO_WritePin(SCL_C_GPIO_Port, SCL_C_Pin, GPIO_PIN_RESET); // 输出低电平
 
-    while (state)
-        ;
-    state = 1;
+    // HACK 考虑RTOS优化
+    HAL_Delay(15);
 
-    // BUG 现在 time 的单位是 1μs
-    if (time_end / 100 < 38) // 判断是否小于38毫秒，大于38毫秒的就是超时，直接调到下面返回0
-    {
-        distance = (time_end * 346) / 2; // 计算距离，25°C空气中的音速为346m/s
-        distance_mm = distance / 100;    // 因为上面的time_end的单位是10微秒，所以要得出单位为毫米的距离结果，还得除以100
-    }
-    return distance_mm; // 返回测距结果
-}
-
-float sonar(void) // 测距并返回单位为米的距离结果
-{
-    uint32_t distance, distance_mm = 0;
-    float distance_m = 0;
-    HAL_GPIO_WritePin(SCL_C_GPIO_Port, SCL_C_Pin, GPIO_PIN_SET);   // 输出高电平
-    delay_us(15);                                                  // 延时15微秒
-    HAL_GPIO_WritePin(SCL_C_GPIO_Port, SCL_C_Pin, GPIO_PIN_RESET); // 输出低电平
-    
-    while (state)
-        ;
-    state = 1;
-
-    // BUG 现在 time 的单位是 1μs
-    if (time_end / 100 < 38)
-    {
-        distance = (time_end * 346) / 2;
-        distance_mm = distance / 100;
-        distance_m = distance_mm / 1000;
-    }
-    return distance_m;
+    if (state)
+        distance = time_end * 346 / 2000; // 计算距离，25°C空气中的音速为346m/s
+    return distance;
 }
 
 void delay_us(uint16_t us)
@@ -72,14 +46,14 @@ void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
     {
         if (HAL_GPIO_ReadPin(SDA_C_EXTI12_GPIO_Port, SDA_C_EXTI12_Pin))
         {
-            HAL_TIM_Base_Start_IT(&htim2);
             time = 0;
+            HAL_TIM_Base_Start_IT(&htim2);
         }
         else
         {
             time_end = time;
             HAL_TIM_Base_Stop_IT(&htim2);
-            state = 0;
+            state = 1;
         }
     }
 }