diff --git a/mcp_can.cpp b/mcp_can.cpp
index f42dc08..d58a481 100644
--- a/mcp_can.cpp
+++ b/mcp_can.cpp
@@ -902,7 +902,7 @@ byte MCP_CAN::readMsgBuf(byte *len, byte buf[])
 ** Function name:           readMsgBufID
 ** Descriptions:            read message buf and can bus source ID
 *********************************************************************************************************/
-byte MCP_CAN::readMsgBufID(byte *ID, byte *len, byte buf[])
+byte MCP_CAN::readMsgBufID(unsigned long *ID, byte *len, byte buf[])
 {
     byte rc;
     rc = readMsg();
@@ -970,4 +970,4 @@ byte MCP_CAN::isExtendedFrame(void)
 
 /*********************************************************************************************************
   END FILE
-*********************************************************************************************************/
+*********************************************************************************************************/
\ No newline at end of file
diff --git a/mcp_can.h b/mcp_can.h
index 7a9bf88..2842e88 100644
--- a/mcp_can.h
+++ b/mcp_can.h
@@ -125,7 +125,7 @@ public:
     byte sendMsgBuf(unsigned long id, byte ext, byte rtr, byte len, byte *buf);     // send buf
     byte sendMsgBuf(unsigned long id, byte ext, byte len, byte *buf);               // send buf
     byte readMsgBuf(byte *len, byte *buf);                          // read buf
-    byte readMsgBufID(byte *ID, byte *len, byte *buf);     // read buf with object ID
+    byte readMsgBufID(unsigned long *ID, byte *len, byte *buf);     // read buf with object ID
     byte checkReceive(void);                                        // if something received
     byte checkError(void);                                          // if something error
     unsigned long getCanId(void);                                   // get can id when receive