Controller Port

The 8 pins of the joypad connector are:

• Pin 1: Vcc
• Pin 2: D0
• Pin 3: D1
• Pin 4: D2
• Pin 5: D3
• Pin 6: SEL
• Pin 7: CLR
• Pin 8: GND

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Joypad Port Access

The joypad port is accessible at the address $1000.

Reading $1000

Reading $1000 returns the states of pins 2, 3, 4, and 5, along with the following information:

Bit	Description
7	CD-ROM base unit presence.
6	Country detection (0: Japan, 1: US).
5	Unused (always 1).
4	Unused (always 1).
3	Joypad port 5 (D3).
2	Joypad port 4 (D2).
1	Joypad port 3 (D1).
0	Joypad port 2 (D0).

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Writing to $1000

Writing to $1000 updates the states of pins 6 and 7:

Bit	Description
1	Joypad port 7 (CLR).
0	Joypad port 6 (SEL).