diff --git a/src/gateware/cxp_pipeline.py b/src/gateware/cxp_pipeline.py
index f440642..61a7787 100644
--- a/src/gateware/cxp_pipeline.py
+++ b/src/gateware/cxp_pipeline.py
@@ -283,6 +283,7 @@ class TX_Test_Packet(Module, AutoCSR):
     def __init__(self, layout):
 
         self.stb = CSR()
+        self.busy = CSRStatus()
 
         # # #
 
@@ -292,7 +293,6 @@ class TX_Test_Packet(Module, AutoCSR):
         # Section 9.9.2 (CXP-001-2021)
         # 0x00, 0x01 ... 0xFF need to be send 16 times 
         # cnt[8:12] is used to count up 16 times while cnt[:8] is the data 
-
         cnt = Signal(max=0x1000)
         clr_cnt = Signal()
         inc_cnt = Signal()
@@ -337,3 +337,10 @@ class TX_Test_Packet(Module, AutoCSR):
         ]
 
         self.source = pak_wrp.source
+
+        self.sync += \
+            If(self.stb.re,
+                self.busy.status.eq(1),
+            ).Elif(self.source.eop & self.source.ack,
+                self.busy.status.eq(0)
+            )