diff --git a/f4/usart/src/usart4.c b/f4/usart/src/usart4.c
index e97a9c7b0bc3472a1446ee5b1e5506cf2532c14a..12413be95528c422f84d7de56fee0f3852b3b90a 100644
--- a/f4/usart/src/usart4.c
+++ b/f4/usart/src/usart4.c
@@ -1,9 +1,9 @@
 #include "usart4.h"
 
-#define     USART                    USART4
-#define     USART_ENABLE_CLK         __HAL_RCC_USART4_CLK_ENABLE()
-#define     USART_IRQn               USART4_IRQn
-#define     USART_IRQHandler         USART4_IRQHandler
+#define     USART                    UART4
+#define     USART_ENABLE_CLK         __HAL_RCC_UART4_CLK_ENABLE()
+#define     USART_IRQn               UART4_IRQn
+#define     USART_IRQHandler         UART4_IRQHandler
 
 #define     USART_TX_PIN             GPIO_PIN_10                
 #define     USART_TX_GPIO_PORT       GPIOC
@@ -182,8 +182,8 @@ void usart4_init(TComm *comm_dev,UART_InitTypeDef *conf,TUSART_IRQ_Priorities *p
   GPIO_InitStructure.Pin       = USART_TX_PIN;
   GPIO_InitStructure.Mode      = GPIO_MODE_AF_PP;
   GPIO_InitStructure.Pull      = GPIO_PULLUP;
-  GPIO_InitStructure.Speed     = GPIO_SPEED_LOW;
-  GPIO_InitStructure.Alternate = GPIO_AF7_USART4;
+  GPIO_InitStructure.Speed     = GPIO_SPEED_FREQ_VERY_HIGH;
+  GPIO_InitStructure.Alternate = GPIO_AF8_UART4;
   HAL_GPIO_Init(USART_TX_GPIO_PORT, &GPIO_InitStructure);
 
   GPIO_InitStructure.Pin       = USART_RX_PIN;