diff --git a/motorApp/MotorSimSrc/Makefile b/motorApp/MotorSimSrc/Makefile
index 76005973..dc3c2f9d 100644
--- a/motorApp/MotorSimSrc/Makefile
+++ b/motorApp/MotorSimSrc/Makefile
@@ -32,6 +32,7 @@ DBD += motorSim.dbd
 
 # motorSim.dbd will be made up from these files:
 motorSim_DBD += base.dbd
+motorSim_DBD += asyn.dbd
 motorSim_DBD += motorSupport.dbd
 motorSim_DBD += motorSimSupport.dbd