diff --git a/docs/edison.md b/docs/edison.md
index 3237701..d55d5dc 100644
--- a/docs/edison.md
+++ b/docs/edison.md
@@ -27,6 +27,7 @@ Intel breakout board
 --------------------
 
 - Both I2C buses are avaible 1 & 6
+- IO on the miniboard is 1.8V
 
 Please see the following table on how the physical pins map to mraa pin numbers