diff --git a/hdk.md b/hdk.md
index c7dc8dc..c023e9e 100644
--- a/hdk.md
+++ b/hdk.md
@@ -22,4 +22,10 @@ The WiFi Pineapple Mark V HDK is an Arduino Pro based microcontroller board feat
   + Flash Memory - 32KB of which 2 KB used by bootloader
   + SRAM - 2 KB (ATmega328)
   + EEPROM - 1 KB (ATmega328)
-  + Clock Speed - 20 MHz
\ No newline at end of file
+  + Clock Speed - 20 MHz
+
+## Pins
+  + HDK PIN 14 -- MK5 GPIO 21
+  + HDK PIN 15 -- MK5 GPIO 20
+  + HDK PIN 16 -- MK5 GPIO 19
+  + HDK PIN 17 -- MK5 GPIO 18