diff --git a/artiq/examples/kc705_nist_clock/repository/ad53xx.py b/artiq/examples/kc705_nist_clock/repository/ad53xx.py
index f10bde057..87da4cd3f 100644
--- a/artiq/examples/kc705_nist_clock/repository/ad53xx.py
+++ b/artiq/examples/kc705_nist_clock/repository/ad53xx.py
@@ -12,7 +12,7 @@ class AD53XXTest(EnvExperiment):
     def run(self):
         self.core.reset()
         delay(5*ms)  # build slack for shift register set
-        self.fmcdio_dirctl.set(self, 0x00008800)
+        self.fmcdio_dirctl.set(0x00008800)
         self.dac.setup_bus()
         self.led.on()
         delay(400*us)