diff --git a/artiq/coredevice/ad9912.py b/artiq/coredevice/ad9912.py
index 0f4b2518d..f8fa875dd 100644
--- a/artiq/coredevice/ad9912.py
+++ b/artiq/coredevice/ad9912.py
@@ -1,7 +1,7 @@
 from numpy import int32, int64
 
 from artiq.language.core import kernel, delay, portable
-from artiq.language.units import us, ns
+from artiq.language.units import ms, us, ns
 from artiq.coredevice.ad9912_reg import *
 
 from artiq.coredevice import spi2 as spi