diff --git a/stanford.json b/stanford.json
index 14a137f..ed7306b 100644
--- a/stanford.json
+++ b/stanford.json
@@ -3,6 +3,7 @@
     "min_artiq_version": "6.0",
     "variant": "stanford",
     "hw_rev": "v2.0",
+    "ext_ref_frequency": 125e6,
     "base": "master",
     "core_addr": "192.168.1.75",
     "peripherals": [