diff --git a/motorApp/Makefile b/motorApp/Makefile
index 45e56d49..42187907 100644
--- a/motorApp/Makefile
+++ b/motorApp/Makefile
@@ -18,6 +18,10 @@ endif
 #DIRS += SoftMotorSrc
 #DIRS += V544Src
 
+ifdef MX
+DIRS += MXmotorSrc
+endif
+
 # The following modules require MPF_SERIAL.
 # Select individual device/driver support modules by removing the comment.
 ifdef MPF_SERIAL