Input devices

The NES and Famicom have a set of I/O ports used for controllers and other peripherals, consisting of the following:

• One output port, 3 bits wide, accessible by writing the bottom 3 bits of $4016.
• Two input ports, each 5 bits wide, accessible by reading the bottom 5 bits of $4016 and $4017.

The NES has two general-purpose controller ports on the front of the console, as well as a (rarely used) 48-pin expansion port underneath.

The Famicom's standard controllers are hardwired to the front of the unit, and a special 15-pin expansion port is commonly used for third-party controllers. The AV Famicom, however, features detachable controllers using the same ports as the NES.

Programmer's reference

• Registers

Hardware

• Arkanoid controller
• Family basic keyboard
• Four score
• Power pad
• Standard controller
• Zapper