Joybus

Specifications

• Bi-directional
• Half-duplex
• Asynchronous
• Idle-high
• Frequency
  • 1 MHz GC/N64
  • 800 kHz Wii

You can poll as fast as you want. Devices with memory (GBA, N64 Transfer Pak) may need more time.

Protocol

Signal	Duty cycle
Zero	¯\____3 us____/¯¯¯¯¯
One	¯\1 us/¯¯¯¯¯¯¯¯¯¯¯¯¯
Console Stop	¯\1 us/¯¯¯¯¯¯¯¯¯
Controller Stop	¯\__2 us__/¯¯¯¯¯¯¯¯¯
Period	¯\______4 us______/¯

General commands

Command	Signal	Resonse
"Reset"	0xFF	Status
"Init"	0x00	Status

Devices

Device	ID
GBA	0x0004
N64 Controller	0x0500
GC Keyboard	0x0820
DK Bongos	0x0900
GC Controller	0x0900

Sample Structures

typedef union {
    uint8_t raw[3]; // struct is 3 bytes long

    struct {
        union {
            uint16_t device; // bytes will be reversed

            struct {
                uint8_t isDolphin : 1;
                uint8_t : 2;
                uint8_t notUltra64 : 2;
                uint8_t noRumble : 1;
                uint8_t : 2;
            };

            struct {
                uint8_t : 1;
                uint8_t fixedState : 1;
                uint8_t radioFreq : 1;
                uint8_t : 3;
                uint8_t receive : 1;
                uint8_t : 1;

                uint8_t type : 4; // 0x0=normal, 0x4=lite, 0x8=non-controller
                uint8_t notBrokenID : 1;
                uint8_t origin : 1;
                uint8_t : 2;
            } wireless;
        };

        union {
            uint8_t state;

            struct {
                uint8_t : 3;
                uint8_t rumble : 1;
                uint8_t : 4;
            };

            struct {
                uint8_t : 1;
                uint8_t receiving : 1;
                uint8_t : 1;
                uint8_t sending : 1;
                uint8_t general : 2;
                uint8_t : 2;
            } gba;
        };
    };
} Joybus_Status_t;

References

1. https://sites.google.com/site/consoleprotocols/home/nintendo-joy-bus-documentation
2. http://hitmen.c02.at/files/yagcd/yagcd/chap9.html#sec9
3. https://github.com/NicoHood/Nintendo/blob/master/src/Gamecube_N64.h
4. http://problemkaputt.de/gbatek.htm#sionormalmode