diff --git a/vd960Loop/utilities/at32f421_freertos_demo/src/main.c b/vd960Loop/utilities/at32f421_freertos_demo/src/main.c
index 9aa4f7b..55cb91a 100644
--- a/vd960Loop/utilities/at32f421_freertos_demo/src/main.c
+++ b/vd960Loop/utilities/at32f421_freertos_demo/src/main.c
@@ -41,6 +41,8 @@ volatile uint8_t usart1_rx_dma_status = 0;
 Pkg_Uart g_pkg_uart_1 = { 0, 0, 0, "", 0};
 Pkg_Uart g_pkg_uart_report = { 0, 0, 0, "", 0};
 static uint8_t tmp_ble_buf[BUFF_STACK_SIZE];
+char usart1_rx_buffer[USART1_RX_BUFFER_SIZE];
+TaskHandle_t usart_task_handler = NULL;
 
 
 /** @addtogroup FreeRTOS_demo