diff --git a/bsp/bsp_can.c b/bsp/bsp_can.c
index c3045eb..57e882d 100644
--- a/bsp/bsp_can.c
+++ b/bsp/bsp_can.c
@@ -86,6 +86,14 @@ void CANTransmit(can_instance *_instance)
     HAL_CAN_AddTxMessage(_instance->can_handle, &_instance->txconf, _instance->tx_buff, &_instance->tx_mailbox);
 }
 
+void CANSetDLC(can_instance *_instance, uint8_t length)
+{
+    if (length > 8)
+        while (1)
+            ;
+    _instance->txconf.DLC = length;
+}
+
 /* -----------------------belows are callback definitions--------------------------*/
 
 /**
@@ -102,11 +110,12 @@ static void CANFIFOxCallback(CAN_HandleTypeDef *_hcan, uint32_t fifox)
     HAL_CAN_GetRxMessage(_hcan, fifox, &rxconf, can_rx_buff);
     for (size_t i = 0; i < DEVICE_CAN_CNT; i++)
     {
-        if(instance[i]!=NULL)
+        if (instance[i] != NULL)
         {
             if (_hcan == instance[i]->can_handle && rxconf.StdId == instance[i]->rx_id)
             {
-                memcpy(instance[i]->rx_buff, can_rx_buff, 8);
+                instance[i]->rx_len=rxconf.DLC;
+                memcpy(instance[i]->rx_buff, can_rx_buff, rxconf.DLC);
                 instance[i]->can_module_callback(instance[i]);
                 break;
             }
diff --git a/bsp/bsp_can.h b/bsp/bsp_can.h
index a14ff09..7ca8948 100644
--- a/bsp/bsp_can.h
+++ b/bsp/bsp_can.h
@@ -19,6 +19,7 @@ typedef struct _
     uint8_t tx_buff[8];
     uint8_t rx_buff[8];
     uint32_t rx_id;
+    uint8_t rx_len;
     void (*can_module_callback)(struct _ *); // callback needs an instance to tell among registered ones
 } can_instance;
 
@@ -49,4 +50,12 @@ void CANTransmit(can_instance *_instance);
  */
 void CANRegister(can_instance *instance, can_instance_config_s config);
 
+/**
+ * @brief 修改CAN发送报文的数据帧长度;注意最大长度为8,在没有进行修改的时候,默认长度为8
+ * 
+ * @param _instance 要修改长度的can实例
+ * @param length    设定长度
+ */
+void CANSetDLC(can_instance *_instance,uint8_t length);
+
 #endif
diff --git a/bsp/bsp_can.md b/bsp/bsp_can.md
index 2f939d6..d8cd7ea 100644
--- a/bsp/bsp_can.md
+++ b/bsp/bsp_can.md
@@ -11,10 +11,6 @@
 
 若你希望新增一个基于CAN的module，首先在该模块下应该有一个包含`can_instance`指针的module结构体（或当功能简单的时候，可以是单独存在的`can_instance`，但不推荐这样做）。
 
-
-
-
-
 ## 代码结构
 
 .h文件内包括了外部接口和类型定义,以及模块对应的宏。c文件内为私有函数和外部接口的定义。
diff --git a/modules/can_comm/can_comm.md b/modules/can_comm/can_comm.md
index 540f1e5..ee1d359 100644
--- a/modules/can_comm/can_comm.md
+++ b/modules/can_comm/can_comm.md
@@ -2,7 +2,10 @@
 
 <p align='right'>neozng1@hnu.edu.cn</p>
 
-双板CAN通信模块
+> TODO:
+>
+> 1. 增加数据长度可变的协议支持
+> 2. 简化接收流程
 
 ## 总览和封装说明