diff --git a/C64_1351_Mouse/README.md b/C64_1351_Mouse/README.md
index 816c76c..d54cf17 100644
--- a/C64_1351_Mouse/README.md
+++ b/C64_1351_Mouse/README.md
@@ -13,8 +13,8 @@ typedef MAX3421e<P18, P19> MAX3421E;
 - 9 (POTX) -> 10k resistor -> 9 (OC1A)
 - 9 (POTX) -> Arduino Pro Micro: 4, Arduino Uno: 8 (ICP1)
 - 5 (POTY) -> 10k resistor -> 10 (OC1B)
-- 6 (FIRE) -> 5
-- 1 (UP) -> 6
+- 6 (FIRE, left mouse button) -> 5
+- 1 (UP, right mouse button) -> 6
 
 #### USB Host Shield (3.3V) -> Arduino
 - SS -> A0 (Arduino Pro Micro) (check UsbCore.h) (3.3V!)