Targets

Interfaces for implementing Joybus targets and N64 accessories. More...

Topics
	GameCube Controller Target
	Joybus target implementation for standard GameCube controllers and WaveBird receivers.
	N64 Controller Target
	Joybus target implementation for standard N64 controllers.

Data Structures
struct	joybus_target_api
	API for implementing a Joybus target. More...
struct	joybus_target
	Interface for a Joybus target, a device on the Joybus which responds to commands from a host. More...

Macros
#define	JOYBUS_TARGET(target)
	Macro to cast a concrete Joybus target instance to a generic Joybus target instance.

Typedefs
typedef void(*	joybus_target_response_cb) (const uint8_t *response, uint8_t len, void *user_data)
	Callback type for sending responses from target command handlers.

Functions
static int	joybus_target_byte_received (struct joybus_target *target, const uint8_t *command, uint8_t byte_idx, joybus_target_response_cb send_response, void *user_data)
	Handle a received command byte for a Joybus target.
static bool	joybus_target_is_registered (struct joybus_target *target)
	Check if a target is currently registered on the bus.

Detailed Description

Interfaces for implementing Joybus targets and N64 accessories.

A Joybus target is a device on the bus that responds to commands from a host (the console), such as an N64 or GameCube controller.

Commands arrive one byte at a time. As each byte is received, libjoybus calls the joybus_target_api::byte_received handler with the bytes accumulated so far. The handler inspects them to decide how many more bytes the command needs, returning the count of bytes still expected.

To send a response, the handler must call the "response ready" callback with a pointer to the (long-lived) response data and its length.

Handlers should call the response callback as soon as the response is ready, even if they are still expecting more command bytes. For many commands, the response data is fully determined by the first few bytes of the command. This allows the backend to start transmitting the response immediately after the last byte is received.

To create your own target, define a struct whose first member is a joybus_target (so it can be cast through JOYBUS_TARGET), point its api at a joybus_target_api table, and register it on a bus with joybus_target_register().

Macro Definition Documentation

JOYBUS_TARGET

#define JOYBUS_TARGET

(

target

)

Value:

((struct joybus_target *)(target))

Macro to cast a concrete Joybus target instance to a generic Joybus target instance.

Typedef Documentation

joybus_target_response_cb

typedef void(* joybus_target_response_cb) (const uint8_t *response, uint8_t len, void *user_data)

Callback type for sending responses from target command handlers.

Parameters

response	the response data to send
len	the length of the response data
user_data	user data passed to the command handler

Function Documentation

joybus_target_byte_received()

int joybus_target_byte_received ( struct joybus_target * target, const uint8_t * command, uint8_t byte_idx, joybus_target_response_cb send_response, void * user_data )

inlinestatic

Handle a received command byte for a Joybus target.

Parameters

target	the target to handle the command
command	the command buffer
byte_idx	the index of the byte that was just received
send_response	a callback function to send the response
user_data	user data to pass to the response callback

Returns

positive number of bytes still expected, 0 if no more bytes expected, a negative joybus_error on failure

joybus_target_is_registered()

bool joybus_target_is_registered ( struct joybus_target * target )

inlinestatic

Check if a target is currently registered on the bus.

Parameters

target

the target to check

Returns

true if the target is registered, false otherwise