diff --git a/megadrive/README.md b/megadrive/README.md
index 6a62f50..b2c58a2 100644
--- a/megadrive/README.md
+++ b/megadrive/README.md
@@ -4,6 +4,8 @@
 - You will need one [Atmega32u4](https://pt.aliexpress.com/item/New-Pro-Micro-ATmega32U4-5V-16MHz-Module-with-2-row-pin-header-For-Leonardo-best-quality/32273120508.html?spm=2114.13010608.0.0.Uv843y&detailNewVersion=&categoryId=400103) (e.g. Arduino Leonardo).
 - [Two DB9 ports](https://pt.aliexpress.com/item/Type-DR9-90-degrees-bend-DR9-male-head-needle-serial-port-and-seat-DB9-RS232-9/32706812789.html?spm=2114.13010608.0.0.1YtDRt), better if you find a 90º version.
 - Original Mega Drive Controller
+- Follow step by step the how-to [`Long version`](https://github.com/mcgurk/Arduino-USB-HID-RetroJoystickAdapter)
+- [Use the file RetroJoystickAdapter_Megadrive.ino](https://raw.githubusercontent.com/mcgurk/Arduino-USB-HID-RetroJoystickAdapter/master/RetroJoystickAdapter_Megadrive.ino), comment the fist set of pins, and uncomment the second that says `// if you use two DB9 connectors solded back to back on your ATmega32u4, you should use this inputs`.
 
 ## Schematics and pinout