diff --git a/cmake/toolchain.cmake b/cmake/toolchain.cmake
index 48937ea..24ac005 100644
--- a/cmake/toolchain.cmake
+++ b/cmake/toolchain.cmake
@@ -94,12 +94,12 @@ set(TARGET_CFLAGS_HARDWARE "-mcpu=cortex-m23 -mfloat-abi=soft -mthumb -mthumb-in
 #set(CMAKE_C_FLAGS_DEBUG     "-DDEBUG=0 -O0 -g")
 #set(CMAKE_CXX_FLAGS_DEBUG   "-DDEBUG=0 -O0 -g")
 #set(CMAKE_ASM_FLAGS_DEBUG   "-DDEBUG=0 -O0 -g")
-set(CMAKE_C_FLAGS_DEBUG     "-DDEBUG=0 -O2 -g")
-set(CMAKE_CXX_FLAGS_DEBUG   "-DDEBUG=0 -O2 -g")
-set(CMAKE_ASM_FLAGS_DEBUG   "-DDEBUG=0 -O2 -g")
-#set(CMAKE_C_FLAGS_DEBUG     "-DDEBUG=0 -Os -g")
-#set(CMAKE_CXX_FLAGS_DEBUG   "-DDEBUG=0 -Os -g")
-#set(CMAKE_ASM_FLAGS_DEBUG   "-DDEBUG=0 -Os -g")
+#set(CMAKE_C_FLAGS_DEBUG     "-DDEBUG=0 -O2 -g")
+#set(CMAKE_CXX_FLAGS_DEBUG   "-DDEBUG=0 -O2 -g")
+#set(CMAKE_ASM_FLAGS_DEBUG   "-DDEBUG=0 -O2 -g")
+set(CMAKE_C_FLAGS_DEBUG     "-DDEBUG=0 -Os -g")
+set(CMAKE_CXX_FLAGS_DEBUG   "-DDEBUG=0 -Os -g")
+set(CMAKE_ASM_FLAGS_DEBUG   "-DDEBUG=0 -Os -g")
 
 # RELEASE
 set(CMAKE_C_FLAGS_RELEASE        "-DNDEBUG -O3") #  -flto
diff --git a/inc/ultrasonic_analog.h b/inc/ultrasonic_analog.h
index d59ac3b..8696a9b 100644
--- a/inc/ultrasonic_analog.h
+++ b/inc/ultrasonic_analog.h
@@ -37,7 +37,7 @@ void ultrasonic_echo_timer_config(void);
 
 void ultrasonic_config(void);
 
-uint32_t ultrasonic_calc_distance(void);
+uint16_t ultrasonic_calc_distance(void);
 
 
 #endif //ULTRASONIC_ANALOG_H
diff --git a/src/gd32e23x_it.c b/src/gd32e23x_it.c
index a966685..acc74b7 100644
--- a/src/gd32e23x_it.c
+++ b/src/gd32e23x_it.c
@@ -34,7 +34,7 @@ OF SUCH DAMAGE.
 
 #include "gd32e23x_it.h"
 
-__IO uint32_t g_capture_value;
+__IO uint16_t g_capture_value;
 
 /*!
     \brief      this function handles NMI exception
diff --git a/src/main.c b/src/main.c
index 14e97f2..9a2fb7f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -8,7 +8,7 @@
 
 volatile uint8_t g_temperature_uint8[2] = {0};
 
-extern uint32_t g_capture_value;
+extern uint16_t g_capture_value;
 uint16_t g_distance_uint16;
 
 /*!
diff --git a/src/rs485_protocol.c b/src/rs485_protocol.c
index b94265d..1a7d70a 100644
--- a/src/rs485_protocol.c
+++ b/src/rs485_protocol.c
@@ -122,22 +122,20 @@ void gd60914_tempture_report(void) {
 // }
 
 void ultrasonic_distance_report(void) {
-    static uint32_t distance_uint32 = 0;
-    static uint8_t package_header[3] = {0xB5, 0xF0, 0x04};
+    static uint16_t distance_uint16 = 0;
+    static uint8_t package_header[3] = {0xB5, 0xF0, 0x02};
     static uint8_t package_data[4] = {0};
 
-    distance_uint32 = ultrasonic_calc_distance();
+    distance_uint16 = ultrasonic_calc_distance();
 
-    package_data[0] = (distance_uint32 >> 24) & 0xFF;
-    package_data[1] = (distance_uint32 >> 16) & 0xFF;
-    package_data[2] = (distance_uint32 >> 8) & 0xFF;
-    package_data[3] = distance_uint32 & 0xFF;
+    package_data[0] = (distance_uint16 >> 8) & 0xFF;
+    package_data[1] = distance_uint16 & 0xFF;
 
     uint8_t combined_data[7];
     memcpy(combined_data, package_header, 3);
-    memcpy(combined_data + 3, package_data, 4);
+    memcpy(combined_data + 3, package_data, 2);
 
     printf("%c%c%c", package_header[0], package_header[1], package_header[2]);
-    printf("%c%c%c%c", package_data[0], package_data[1], package_data[2], package_data[3]);
-    printf("%c", calculate_crc(combined_data, 8));
+    printf("%c%c", package_data[0], package_data[1]);
+    printf("%c", calculate_crc(combined_data, 6));
 }
diff --git a/src/ultrasonic_analog.c b/src/ultrasonic_analog.c
index 70bd4af..10ef5b5 100644
--- a/src/ultrasonic_analog.c
+++ b/src/ultrasonic_analog.c
@@ -139,10 +139,10 @@ void ultrasonic_config(void) {
     ultrasonic_echo_timer_config();
 }
 
-uint32_t ultrasonic_calc_distance(void) {
+uint16_t ultrasonic_calc_distance(void) {
     while (!ultrasonicMeasurementDone);
     // uint32_t us_value = timer_channel_capture_value_register_read(US_ECHO_TIMER, US_ECHO_CH);
-    uint32_t distance = (TIME_CORRECTION_US + g_capture_value) * 17;
+    uint16_t distance = (TIME_CORRECTION_US + g_capture_value) * 17;
     /*
      *  (TIME_CORRECTION_US + us_value) * 340 m/s
      *  -----------------------------------------