diff --git a/README.md b/README.md
index f89a358..0293572 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,7 @@ JP1
  3 ┣━ Red LED (GPIO4)
  2 ┣━ Green LED (GPIO18)
    ┣━ White LED (GPIO23)
+   ┣━ USB power probe (GPIO33)
 ━━━┛
 
 ```