Famicom Network Controller

The Famicom Network Controller is a 23-button controller, part number HVC-051, for use with the Famicom Network System. In addition to the 8 buttons provided by the standard controller, it provides another 15 buttons.

Layout

 .------------------------------------------.
 | (<)   (>)  (1) (2) (3) (*) (C)           |
 | SEL _ STA                        (END)   |
 |   _| |_    (4) (5) (6) (#) (.)           |
 |  |_   _|                                 |
 |    |_|     (7) (8) (9) (  0  )  (B)  (A) |
 '------------------------------------------'

ASCII art courtesy Nocash

• The Select button has the additional text 前パージ = Previous Page
• The Start button has the additional text 次パージ = Next Page
• The B button has the additional text 目次 = Table of Contents
• The A button has the additional text 実行 = Execute
• The button marked "END" instead has the text 通信終了 = End of Communication

Protocol

The protocol looks like a standard Famicom expansion port controller, returning its result via reads from $4016 on the 2s bit ("D1"). After the initial eight reads, the following sixteen reads return the following bits in order:

 0-7 - see Standard controller
 8 - 0
 9 - 1
10 - 2
11 - 3
12 - 4
13 - 5
14 - 6
15 - 7
16 - 8
17 - 9
18 - *
19 - #
20 - .
21 - C
22 - (Always 0)
23 - 通信終了

Like the standard controller, reads after the first 24 read as logic 1.

Sources

• Raphnet
• astro187 on the forum