diff --git a/indiana.json b/indiana.json
index 59effc4..7a7e0da 100644
--- a/indiana.json
+++ b/indiana.json
@@ -3,6 +3,7 @@
     "variant": "indiana",
     "hw_rev": "v1.1",
     "base": "standalone",
+    "ext_ref_frequency": 10e6,
     "core_addr": "192.168.1.75",
     "peripherals": [
         {