diff --git a/Hardware-documentation.md b/Hardware-documentation.md
index d44b62a..ef71e67 100644
--- a/Hardware-documentation.md
+++ b/Hardware-documentation.md
@@ -3,6 +3,7 @@
 
 # Broadcom platform
 * [[PCIe interface]]
+* [[S2 PLLs]]
 * [[DDR memory controller]]
 * [[Power management]]