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.
  • The values latched by $4016/write appear on the OUT0-OUT2 output pins of the 2A03/07, where OUT0 is routed to the controller ports and OUT0-OUT2 to the expansion port on the NES.
• Two input ports, each 5 bits wide, accessible by reading the bottom 5 bits of $4016 and $4017.
  • Only D0 and D3-D4 are connected to the controller ports, while the expansion port receives all the bits (D0-D4). Reading $4016 and $4017 activates the /OE1 and /OE2 signals, respectively, which are routed to the controller ports and the expansion port.

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
• Controller port pinout
• Family basic keyboard
• Four score
• Power Pad
• Standard controller
• Zapper
• Oeka Kids tablet
• Miracle Piano
• RacerMate Bicycle
• Power Glove
• U-Force
• Mouse

Other I/O devices

• Famicom 3D glasses
• Family BASIC Data Recorder
• R. O. B.
• Battle Box
• Turbo File
• Barcode Battler