ADB(4) BSD Kernel Interfaces Manual ADB(4)
adb -- Apple Desktop Bus driver
adb* at obio?
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,
trackpads, trackballs, and graphics tablets to the machine. NetBSD provides support for the
Apple Desktop Bus as found on all supported mac68k models, as well as macppc models with on-
board ADB (PowerBooks and ``Old World'' models).
The adb driver accesses the ADB controller using the so-called ``HWDIRECT'' method. This
method of access bypasses the Macintosh ROM and uses only NetBSD routines for ADB access.
This is the only method supported on macppc and is the default for mac68k systems.
On mac68k systems there is an alternate method of accessing the ADB controller. With the
Macintosh ROM Glue (MRG) method, the routines written for MacOS are used. To enable this
method of ADB access, uncomment the line:
in your kernel configuration file.
The ioctl(2) call is used to control the ADB event device. The following is a list of
available ioctl(2) 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 cur-
rent address, default address, and handler ID for the corresponding ADB
ADBIOC_GETREPEAT Get Keyboard Repeat Info
Returns a structure containing the current keyboard repeat delay and key-
board repeat interval.
ADBIOC_SETREPEAT Set Keyboard Repeat Rate
Sets the keyboard repeat delay and interval to the values specified by
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 com-
mand is not fully implemented at this time.
NetBSD includes support for the following ADB devices, sorted by driver name:
abtn ADB mouse button?
aed ADB event device
akbd ADB keyboard
ams ADB mouse
apm APM emulation
/dev/adb The ADB event device.
aed0 at adb0 addr 0: ADB Event device This is a normal autoconfiguration message noting the
presence of the adb event device.
adb0 at obio0 offset 0x16000 irq 18: 2 targets A standard autoconfiguration message indi-
cating the initialization of the ADB subsystem.
adb: no devices found. No ADB devices were found to be connected to the bus during autocon-
adb: using %s series hardware support. Indicates the class of ADB hardware support the
adb: hardware type unknown for this machine. The ADB hardware in this machine is currently
adb: no ROM ADB driver in this kernel for this machine. The kernel lacks the necessary Mac-
intosh 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
adb: %s at %d. An ADB device of the type specified by %s has been found at location %d.
aed(4), akbd(4), ams(4), apm(4)
The adb interface first appeared in NetBSD 0.9. It has been under development ever since.
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.
o Not every class of ADB hardware is supported yet.
o The talk command is currently unimplemented.
o The listen command is not implemented yet.
o Not all multi-button mice are currently supported.
o Only mapped and relative-position ADB devices (i.e. keyboards and mice) are supported.
Thus absolute-position and other exotic devices will not work.
o Some of the diagnostic messages in this man page need to be updated.
Some mac68k machines contain so-called dirty ROM. These machines are the: Mac SE/30, Mac
II, Mac IIx, and Mac IIcx. Machines with dirty ROM may experience trouble booting if the
MRG code is used, especially under the following conditions:
o Both a keyboard and a mouse are not attached to the computer.
o An extended keyboard is attached to the computer.
On (some) machines with dirty ROM, the ROM indicates the presence of a ``ghost'' keyboard or
mouse. When this non-existant device is probed for, the result is an infinite loop. This
is believed to be triggered by the adb driver probing for extended mice, and non-EMP Log-
BSD September 21, 2003 BSD