From 9cdd0008a530a2441ad701b4ae7027235856dab7 Mon Sep 17 00:00:00 2001
From: yelvlab <wanghao19950516@gmail.com>
Date: Wed, 25 Sep 2024 17:25:07 +0800
Subject: [PATCH] Convert ultrasonic flight time to distance value

---
 src/main.c              |  3 +++
 src/ultrasonic_driver.c | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/src/main.c b/src/main.c
index f5edcb0..c396c80 100644
--- a/src/main.c
+++ b/src/main.c
@@ -13,6 +13,7 @@
 #include "ultrasonic_driver.h"
 
 extern uint32_t capture_value;
+uint16_t distance_uint16;
 
 /*!
     \brief      main function
@@ -52,6 +53,8 @@ int main(void)
         // printf("Send ultra sonic driver signal!\r\n");
     delay_ms(2);
         printf("cap_val:%ld\n", capture_value);
+        distance_uint16 = calculate_distance(capture_value);
+        printf("Distance:%d\n", distance_uint16);
     }
 }
 
diff --git a/src/ultrasonic_driver.c b/src/ultrasonic_driver.c
index 746f34a..cd2274c 100644
--- a/src/ultrasonic_driver.c
+++ b/src/ultrasonic_driver.c
@@ -177,3 +177,15 @@ void ultrasonic_echo_timer_config(void)
     timer_icinitpara.icfilter = 0x03; // 设置滤波器
     timer_input_capture_config(US_ECHO_TIMER, US_ECHO_CH, &timer_icinitpara);
 }
+
+uint16_t calculate_distance(uint32_t us_value) {
+    uint16_t distace = (TIME_CORRECTION_US + us_value) * 17;
+    /*
+     *  (TIME_CORRECTION_US + us_value) * 340 m/s
+     *  -----------------------------------------
+     *                  1000 000
+     *  ----------------------------------------------
+     *                          2
+     */
+    return distace;
+}