diff --git a/artiq/coredevice/zotino.py b/artiq/coredevice/zotino.py
index 19eeca6c2..e56842be5 100644
--- a/artiq/coredevice/zotino.py
+++ b/artiq/coredevice/zotino.py
@@ -34,7 +34,7 @@ class Zotino(AD53xx):
     :param core_device: Core device name (default: "core")
     """
 
-    def __init__(self, dmgr, spi_device, ldac_device, clr_device,
+    def __init__(self, dmgr, spi_device, ldac_device=None, clr_device=None,
                  div_write=4, div_read=8, vref=5., core="core"):
         AD53xx.__init__(self, dmgr=dmgr, spi_device=spi_device,
                         ldac_device=ldac_device, clr_device=clr_device,