Because I have no idea about pinout of this keyboard. I ended up borrowing Arduino Mega 2560 from my friend living next door for this project. I wrote a small(?) code that use roughly 16 GPIOs to scan each pin. By the scanning pin set as input pull-up mode, other pin as output with logic 0. When button is pressed, it completes the circuit and pull the input pin down to GND level. With this setup I can easily map out every single button and create buttons matrix map. Unfortunately, my hardware setup is to cozy and I need to put the keyboard in weird angle. Ended up tearing the FFC cable. I be able to only map few pins, Until the new keyboard arrive. This is by far the most mapping I can get :