diff --git a/Core/Inc/main.h b/Core/Inc/main.h
index 887cfc3..4712bc0 100644
--- a/Core/Inc/main.h
+++ b/Core/Inc/main.h
@@ -57,6 +57,8 @@ void Error_Handler(void);
 /* USER CODE END EFP */
 
 /* Private defines -----------------------------------------------------------*/
+#define LED_ACT_Pin GPIO_PIN_1
+#define LED_ACT_GPIO_Port GPIOC
 #define U_CTRL_Pin GPIO_PIN_4
 #define U_CTRL_GPIO_Port GPIOA
 #define I_CTRL_Pin GPIO_PIN_5
diff --git a/Core/Src/main.c b/Core/Src/main.c
index f66636f..4db2e00 100644
--- a/Core/Src/main.c
+++ b/Core/Src/main.c
@@ -44,6 +44,7 @@ ADC_HandleTypeDef hadc1;
 
 DAC_HandleTypeDef hdac;
 
+UART_HandleTypeDef huart4;
 UART_HandleTypeDef huart1;
 DMA_HandleTypeDef hdma_usart1_rx;
 DMA_HandleTypeDef hdma_usart1_tx;
@@ -59,6 +60,7 @@ static void MX_DMA_Init(void);
 static void MX_USART1_UART_Init(void);
 static void MX_DAC_Init(void);
 static void MX_ADC1_Init(void);
+static void MX_UART4_Init(void);
 /* USER CODE BEGIN PFP */
 
 /* USER CODE END PFP */
@@ -101,6 +103,7 @@ int main(void)
   MX_USART1_UART_Init();
   MX_DAC_Init();
   MX_ADC1_Init();
+  MX_UART4_Init();
   /* USER CODE BEGIN 2 */
 
   /* USER CODE END 2 */
@@ -260,6 +263,39 @@ static void MX_DAC_Init(void)
 
 }
 
+/**
+  * @brief UART4 Initialization Function
+  * @param None
+  * @retval None
+  */
+static void MX_UART4_Init(void)
+{
+
+  /* USER CODE BEGIN UART4_Init 0 */
+
+  /* USER CODE END UART4_Init 0 */
+
+  /* USER CODE BEGIN UART4_Init 1 */
+
+  /* USER CODE END UART4_Init 1 */
+  huart4.Instance = UART4;
+  huart4.Init.BaudRate = 115200;
+  huart4.Init.WordLength = UART_WORDLENGTH_8B;
+  huart4.Init.StopBits = UART_STOPBITS_1;
+  huart4.Init.Parity = UART_PARITY_NONE;
+  huart4.Init.Mode = UART_MODE_TX_RX;
+  huart4.Init.HwFlowCtl = UART_HWCONTROL_NONE;
+  huart4.Init.OverSampling = UART_OVERSAMPLING_16;
+  if (HAL_UART_Init(&huart4) != HAL_OK)
+  {
+    Error_Handler();
+  }
+  /* USER CODE BEGIN UART4_Init 2 */
+
+  /* USER CODE END UART4_Init 2 */
+
+}
+
 /**
   * @brief USART1 Initialization Function
   * @param None
@@ -325,22 +361,22 @@ static void MX_GPIO_Init(void)
 
   /* GPIO Ports Clock Enable */
   __HAL_RCC_GPIOD_CLK_ENABLE();
-  __HAL_RCC_GPIOA_CLK_ENABLE();
   __HAL_RCC_GPIOC_CLK_ENABLE();
+  __HAL_RCC_GPIOA_CLK_ENABLE();
   __HAL_RCC_GPIOB_CLK_ENABLE();
 
   /*Configure GPIO pin Output Level */
-  HAL_GPIO_WritePin(HVS_ENABLE_GPIO_Port, HVS_ENABLE_Pin, GPIO_PIN_RESET);
+  HAL_GPIO_WritePin(GPIOC, LED_ACT_Pin|HVS_ENABLE_Pin, GPIO_PIN_RESET);
 
   /*Configure GPIO pin Output Level */
   HAL_GPIO_WritePin(TXEN_GPIO_Port, TXEN_Pin, GPIO_PIN_RESET);
 
-  /*Configure GPIO pin : HVS_ENABLE_Pin */
-  GPIO_InitStruct.Pin = HVS_ENABLE_Pin;
+  /*Configure GPIO pins : LED_ACT_Pin HVS_ENABLE_Pin */
+  GPIO_InitStruct.Pin = LED_ACT_Pin|HVS_ENABLE_Pin;
   GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
   GPIO_InitStruct.Pull = GPIO_NOPULL;
   GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
-  HAL_GPIO_Init(HVS_ENABLE_GPIO_Port, &GPIO_InitStruct);
+  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
 
   /*Configure GPIO pins : HVS_OVERLOAD_Pin HVS_OVERHEAT_Pin */
   GPIO_InitStruct.Pin = HVS_OVERLOAD_Pin|HVS_OVERHEAT_Pin;
diff --git a/Core/Src/stm32f1xx_hal_msp.c b/Core/Src/stm32f1xx_hal_msp.c
index 473853b..4f5c62b 100644
--- a/Core/Src/stm32f1xx_hal_msp.c
+++ b/Core/Src/stm32f1xx_hal_msp.c
@@ -228,7 +228,34 @@ void HAL_DAC_MspDeInit(DAC_HandleTypeDef* hdac)
 void HAL_UART_MspInit(UART_HandleTypeDef* huart)
 {
   GPIO_InitTypeDef GPIO_InitStruct = {0};
-  if(huart->Instance==USART1)
+  if(huart->Instance==UART4)
+  {
+  /* USER CODE BEGIN UART4_MspInit 0 */
+
+  /* USER CODE END UART4_MspInit 0 */
+    /* Peripheral clock enable */
+    __HAL_RCC_UART4_CLK_ENABLE();
+
+    __HAL_RCC_GPIOC_CLK_ENABLE();
+    /**UART4 GPIO Configuration
+    PC10     ------> UART4_TX
+    PC11     ------> UART4_RX
+    */
+    GPIO_InitStruct.Pin = GPIO_PIN_10;
+    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
+    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
+    HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
+
+    GPIO_InitStruct.Pin = GPIO_PIN_11;
+    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
+    GPIO_InitStruct.Pull = GPIO_NOPULL;
+    HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
+
+  /* USER CODE BEGIN UART4_MspInit 1 */
+
+  /* USER CODE END UART4_MspInit 1 */
+  }
+  else if(huart->Instance==USART1)
   {
   /* USER CODE BEGIN USART1_MspInit 0 */
 
@@ -304,7 +331,25 @@ void HAL_UART_MspInit(UART_HandleTypeDef* huart)
 */
 void HAL_UART_MspDeInit(UART_HandleTypeDef* huart)
 {
-  if(huart->Instance==USART1)
+  if(huart->Instance==UART4)
+  {
+  /* USER CODE BEGIN UART4_MspDeInit 0 */
+
+  /* USER CODE END UART4_MspDeInit 0 */
+    /* Peripheral clock disable */
+    __HAL_RCC_UART4_CLK_DISABLE();
+
+    /**UART4 GPIO Configuration
+    PC10     ------> UART4_TX
+    PC11     ------> UART4_RX
+    */
+    HAL_GPIO_DeInit(GPIOC, GPIO_PIN_10|GPIO_PIN_11);
+
+  /* USER CODE BEGIN UART4_MspDeInit 1 */
+
+  /* USER CODE END UART4_MspDeInit 1 */
+  }
+  else if(huart->Instance==USART1)
   {
   /* USER CODE BEGIN USART1_MspDeInit 0 */
 
diff --git a/RS485_BSV.ioc b/RS485_BSV.ioc
index c010ecc..3258639 100644
--- a/RS485_BSV.ioc
+++ b/RS485_BSV.ioc
@@ -39,33 +39,37 @@ Mcu.IP2=DMA
 Mcu.IP3=NVIC
 Mcu.IP4=RCC
 Mcu.IP5=SYS
-Mcu.IP6=USART1
-Mcu.IPNb=7
+Mcu.IP6=UART4
+Mcu.IP7=USART1
+Mcu.IPNb=8
 Mcu.Name=STM32F103R(C-D-E)Tx
 Mcu.Package=LQFP64
 Mcu.Pin0=PD0-OSC_IN
 Mcu.Pin1=PD1-OSC_OUT
-Mcu.Pin10=PC9
-Mcu.Pin11=PA8
-Mcu.Pin12=PA9
-Mcu.Pin13=PA10
-Mcu.Pin14=PA11
-Mcu.Pin15=PA13
-Mcu.Pin16=PA14
-Mcu.Pin17=PB3
-Mcu.Pin18=PB5
-Mcu.Pin19=PB6
-Mcu.Pin2=PA4
-Mcu.Pin20=PB7
-Mcu.Pin21=VP_SYS_VS_Systick
-Mcu.Pin3=PA5
-Mcu.Pin4=PA6
-Mcu.Pin5=PA7
-Mcu.Pin6=PC4
-Mcu.Pin7=PC5
-Mcu.Pin8=PC7
-Mcu.Pin9=PC8
-Mcu.PinsNb=22
+Mcu.Pin10=PC8
+Mcu.Pin11=PC9
+Mcu.Pin12=PA8
+Mcu.Pin13=PA9
+Mcu.Pin14=PA10
+Mcu.Pin15=PA11
+Mcu.Pin16=PA13
+Mcu.Pin17=PA14
+Mcu.Pin18=PC10
+Mcu.Pin19=PC11
+Mcu.Pin2=PC1
+Mcu.Pin20=PB3
+Mcu.Pin21=PB5
+Mcu.Pin22=PB6
+Mcu.Pin23=PB7
+Mcu.Pin24=VP_SYS_VS_Systick
+Mcu.Pin3=PA4
+Mcu.Pin4=PA5
+Mcu.Pin5=PA6
+Mcu.Pin6=PA7
+Mcu.Pin7=PC4
+Mcu.Pin8=PC5
+Mcu.Pin9=PC7
+Mcu.PinsNb=25
 Mcu.ThirdPartyNb=0
 Mcu.UserConstants=
 Mcu.UserName=STM32F103RCTx
@@ -129,6 +133,14 @@ PB6.Signal=USART1_TX
 PB7.Locked=true
 PB7.Mode=Asynchronous
 PB7.Signal=USART1_RX
+PC1.GPIOParameters=GPIO_Label
+PC1.GPIO_Label=LED_ACT
+PC1.Locked=true
+PC1.Signal=GPIO_Output
+PC10.Mode=Asynchronous
+PC10.Signal=UART4_TX
+PC11.Mode=Asynchronous
+PC11.Signal=UART4_RX
 PC4.GPIOParameters=GPIO_Label
 PC4.GPIO_Label=HVS_24V
 PC4.Signal=ADCx_IN14
@@ -224,6 +236,8 @@ SH.COMP_DAC2_group.0=DAC_OUT2,DAC_OUT2
 SH.COMP_DAC2_group.ConfNb=1
 SH.GPXTI11.0=GPIO_EXTI11
 SH.GPXTI11.ConfNb=1
+UART4.IPParameters=VirtualMode
+UART4.VirtualMode=Asynchronous
 USART1.BaudRate=9600
 USART1.IPParameters=VirtualMode,BaudRate
 USART1.VirtualMode=VM_ASYNC