BotronikS - Final code for all types of Arduino and PC users: -- HOME -- email: botronik@gmail.com
What you need to install or have installed before on your PC: see HERE

Control 16 outputs from PC
Upload this HEX code in Arduino Mega or Controllino Mega: Here
Test and use this PC application: Here or BotPcApp16o
Text commands: ABCDEFGHIJKLMNOP/abcdefghijklmnop turns Out1-Out16 ON/OFF