diff --git a/GPIO/iCE40/ring.v b/GPIO/iCE40/ring.v
index 7fd665c891721decfdb1787a51a29a614bfbe945..e55881cb1a4fde8321013388f459ed48c6392273 100644
--- a/GPIO/iCE40/ring.v
+++ b/GPIO/iCE40/ring.v
@@ -1,4 +1,18 @@
-// Cause yosys to throw an error when we implicitly declare nets
+//
+// ring.v
+//
+// iCE40 FPGA ring oscillator test
+//
+// Erik Strand 9/30/21
+//
+// This work may be reproduced, modified, distributed,
+// performed, and displayed for any purpose, but must
+// acknowledge this project. Copyright is retained and
+// must be preserved. The work is provided as is; no
+// warranty is provided, and users accept all liability.
+//
+
+// Make yosys throw an error when we implicitly declare nets.
 `default_nettype none
 
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