diff --git a/src/main/scala/backBoard/ebus/CDRIn.scala b/src/main/scala/backBoard/ebus/CDRIn.scala
index ba3958e..fae6248 100644
--- a/src/main/scala/backBoard/ebus/CDRIn.scala
+++ b/src/main/scala/backBoard/ebus/CDRIn.scala
@@ -123,7 +123,7 @@ trait CDRInAxis{ this: CDRInBase =>
   when( byteCnt === 0.U & bitCnt === 9.U & stateCurr === STATE_HEADER ){
     payloadLen := Cat( shiftData ^ Mux( encryptor.io.op.valid, encryptor.io.op.bits, 0.U ), 0.U(4.W) )
   } .elsewhen( byteCnt === 1.U & bitCnt === 9.U & stateCurr === STATE_HEADER ){
-    payloadLen := Cat( payloadLen(11,4), shiftData(7,4) ^ Mux( encryptor.io.op.valid, encryptor.io.op.bits, 0.U ) )
+    payloadLen := Cat( payloadLen(11,4), shiftData(7,4) ^ Mux( encryptor.io.op.valid, encryptor.io.op.bits(7,4), 0.U ) )
   }
   
   stateNext :=