diff --git a/hw2master.json b/hw2master.json
index 89f3ad6..e7ce24a 100644
--- a/hw2master.json
+++ b/hw2master.json
@@ -5,6 +5,7 @@
     "base": "master",
     "core_addr": "192.168.1.75",
     "enable_sata_drtio": true,
+    "ext_ref_frequency": 10e6,
     "peripherals": [
         {
             "type": "grabber",