ADB(4)

NAME
adb - Apple Desktop Bus event interface

SYNOPSIS
adb0 at obio?
options MRG_ADB
#include <machine/adbsys.h>

DESCRIPTION
The Apple Desktop Bus (ADB) is the single-master, multiple-slave, low-speed serial bus interface used by Macintosh computers to connect input devices such as keyboards, mice, trackballs, and graphics tablets to the machine.

The adb device is the sole interface to user input. It combines both keyboard and mouse drivers into one event driver. All user input is obtained by doing a read(2) on the adb device. Since most Macintosh mice have only one button, the adb driver will emulate a second and third mouse button with the keyboard. The adb device only supports being opened by one process at a time.

There are two interfaces to the ADB hardware supported by the adb driver. The older of the two relies on information in the Macintosh ROM to interface with the hardware. This method is only available if the MRG_ADB option is defined in the kernel configuration file. The newer method interfaces directly with the VIA hardware and with the Power Manager hardware if it is present (i.e. on the PowerBooks). The default configuration currently uses the Macintosh ROM Glue (MRG) method.

The ioctl(2) call is used to control the ADB event device. The following is a list of available ioctl commands:

ADBIOC_DEVSINFO
    Get ADB Device Info

    The adb event device will return an array of information containing an entry for each device connected to the bus. Each entry contains the current address, default address, and handler ID for the corresponding ADB device.

ADBIOC_GETREPEAT
    Get Keyboard Repeat Info

    Returns a structure containing the current keyboard repeat delay and keyboard repeat interval.

ADBIOC_SETREPEAT
    Set Keyboard Repeat Rate

    Sets the keyboard repeat delay and interval to the values specified by argp.

ADBIOC_RESET
    ADB Reset

    Perform a reset of the ADB which will reinitialize all of the devices attached to the bus.

ADBIOC_LISTENCMD
    ADB Listen Command

    Send data to the register of the ADB device specified by argp. This command is not fully implemented at this time.

HARDWARE
The adb device supports the ADB hardware of most m68k-based Macintosh models, including the II-series, Centris- and Quadra-series, PowerBook- and Duo-series, LC-series, and Performa-series models.

Most standard ADB devices are supported by the adb driver, including mice which follow Apple's Extended Mouse Protocol. Many multi-button mice which follow a proprietary protocol are not currently supported in multi-button mode. The following is a partial list of supported ADB devices:

Apple Standard Keyboard
Apple Extended Keyboard
Apple Adjustable Keyboard
Apple Desktop Bus Mouse
Logitech TrackMan
Logitech MouseMan
Microspeed Mouse Deluxe
Mouse Systems A3 Mouse

DIAGNOSTICS
adb0 at obio0 (ADB event device). This is a normal autoconfiguration message noting the presence of the adb event device.
adb: bus subsystem. A standard autoconfiguration message indicating the initialization of the ADB subsystem.
adb: no devices found. No ADB devices were found to be connected to the bus during autoconfiguration.
adb: using %s series hardware support. Indicates the class of ADB hardware support the machine uses.
adb: hardware type unknown for this machine. The ADB hardware in this machine is currently unsupported.
adb: no ROM ADB driver in this kernel for this machine. The kernel lacks the necessary Macintosh ROM Glue (MRG) support for accessing the ADB hardware on this machine.
adb: using serial console. A serial console will be used for user input rather than the ADB event device.
adb: %s at %d. An ADB device of the type specified by %s has been found at location %d.

ERRORS

[ENXIO]
    No such ADB event device.

[EBUSY]
    Another process has the device open.

[EINVAL]
    Invalid ioctl specification.

[EMSGSIZE]
    The size of the ADB event being read is too large to fit into the buffer allocated to it.

FILES
/dev/adb
    The ADB event device.

HISTORY
The adb interface first appeared in NetBSD 0.9. It has been under development ever since.

AUTHORS
Bradley A. Grantham wrote the original adb driver, including the MRG support. The hardware direct interface was written by John P. Wittkowski. The PowerManager interface was written by Takashi Hamada.

BUGS

•   Not every class of ADB hardware is supported yet.

•   The talk command is currently unimplemented.

•   The listen command is not implemented yet.

•   Not all multi-button mice are currently supported.

•   Only mapped and relative-position ADB devices (i.e. keyboards and mice) are supported. Thus absolute-position and other exotic devices will not work.