diff --git a/CMakeLists.txt b/CMakeLists.txt
index efb9a6f..713384c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -29,6 +29,7 @@ set(TARGET_C_SRC
         ${CMAKE_SOURCE_DIR}/src/systick.c
         ${CMAKE_SOURCE_DIR}/src/ultrasonic_driver.c
         ${CMAKE_SOURCE_DIR}/src/mlx90614.c
+        ${CMAKE_SOURCE_DIR}/src/RS485.c
 )
 
 add_executable(xlsw_3dp_ultrasonic_300K ${TARGET_C_SRC})
diff --git a/inc/RS485.h b/inc/RS485.h
new file mode 100644
index 0000000..ee2dbd0
--- /dev/null
+++ b/inc/RS485.h
@@ -0,0 +1,11 @@
+//
+// Created by dell on 24-11-29.
+//
+
+#ifndef RS485_H
+#define RS485_H
+
+#include <stdbool.h>
+#include <string.h>
+
+#endif //RS485_H
diff --git a/src/RS485.c b/src/RS485.c
new file mode 100644
index 0000000..16d6164
--- /dev/null
+++ b/src/RS485.c
@@ -0,0 +1,29 @@
+//
+// Created by dell on 24-11-29.
+//
+
+#include "RS485.h"
+#include "gd32e23x.h"
+#include "systick.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAX_CMD_SIZE 16
+#define BUFSIZE 8
+
+static char cmdbuffer[BUFSIZE][MAX_CMD_SIZE];
+static char *strchr_pointer = NULL;
+
+static int bufindr = 0;
+static int bufindw = 0;
+static int buflen = 0;
+
+bool code_seen(char code)
+{
+    strchr_pointer = strchr(cmdbuffer[bufindr], code);
+    return (strchr_pointer != NULL);  //Return True if a character was found
+}
+float code_value(void)
+{
+    return (strtod(&cmdbuffer[bufindr][strchr_pointer - cmdbuffer[bufindr] + 1], NULL));
+}
\ No newline at end of file
diff --git a/src/ultrasonic_driver.c b/src/ultrasonic_driver.c
index 2877c80..bc7c7ae 100644
--- a/src/ultrasonic_driver.c
+++ b/src/ultrasonic_driver.c
@@ -46,8 +46,9 @@ void usart_config(void)
     gpio_output_options_set(USART_GPIO_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, USART_TX_PIN | USART_RX_PIN);
 
     /* configure RS485 EN Pin */
-    gpio_mode_set(USART_GPIO_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_PULLUP, USART_EN_PIN);
+    gpio_mode_set(USART_GPIO_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, USART_EN_PIN);
     gpio_output_options_set(USART_GPIO_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, USART_EN_PIN);
+    gpio_bit_write(USART_GPIO_PORT, USART_EN_PIN, SET);
 
     /* USART configure */
     usart_deinit(USART0_PHY);