atarikbd.txt

linux 内核源代码

Intelligent Keyboard (ikbd) Protocol


1. Introduction

The Atari Corp. Intelligent Keyboard (ikbd) is a general purpose keyboard
controller that is flexible enough that it can be used in a variety of
products without modification. The keyboard, with its microcontroller,
provides a convenient connection point for a mouse and switch-type joysticks.
The ikbd processor also maintains a time-of-day clock with one second
resolution.
The ikbd has been designed to be general enough that it can be used with a
variety of new computer products. Product variations in a number of
keyswitches, mouse resolution, etc. can be accommodated.
The ikbd communicates with the main processor over a high speed bi-directional
serial interface. It can function in a variety of modes to facilitate
different applications of the keyboard,  joysticks, or mouse. Limited use of
the controller is possible in applications in which only a unidirectional
communications medium is available by carefully designing the default modes.

3. Keyboard

The keyboard always returns key make/break scan codes. The ikbd generates
keyboard scan codes for each key press and release. The key scan make (key
closure) codes start at 1, and are defined in Appendix A. For example, the
ISO key position in the scan code table should exist even if no keyswitch
exists in that position on a particular keyboard. The break code for each key
is obtained by ORing 0x80 with the make code.

The special codes 0xF6 through 0xFF are reserved for use as follows:
    0xF6            status report
    0xF7            absolute mouse position record
    0xF8-0xFB       relative mouse position records (lsbs determined by
                     mouse button states)
    0xFC            time-of-day
    0xFD            joystick report (both sticks)
    0xFE            joystick 0 event
    0xFF            joystick 1 event

The two shift keys return different scan codes in this mode. The ENTER key
and the RETurn key are also distinct.

4. Mouse

The mouse port should be capable of supporting a mouse with resolution of
approximately 200 counts (phase changes or 'clicks') per inch of travel. The
mouse should be scanned at a rate that will permit accurate tracking at
velocities up to 10 inches per second.
The ikbd can report mouse motion in three distinctly different ways. It can
report relative motion, absolute motion in a coordinate system maintained
within the ikbd, or by converting mouse motion into keyboard cursor control
key equivalents.
The mouse buttons can be treated as part of the mouse or as additional
keyboard keys.

4.1 Relative Position Reporting

In relative position mode, the ikbd will return relative mouse position
records whenever a mouse event occurs. A mouse event consists of a mouse
button being pressed or released, or motion in either axis exceeding a
settable threshold of motion. Regardless of the threshold, all bits of
resolution are returned to the host computer.
Note that the ikbd may return mouse relative position reports with
significantly more than the threshold delta x or y. This may happen since no
relative mouse motion events will be generated: (a) while the keyboard has
been 'paused' ( the event will be stored until keyboard communications is
resumed) (b) while any event is being transmitted.

The relative mouse position record is a three byte record of the form
(regardless of keyboard mode):
    %111110xy           ; mouse position record flag
                        ; where y is the right button state
                        ; and x is the left button state
    X                   ; delta x as twos complement integer
    Y                   ; delta y as twos complement integer

Note that the value of the button state bits should be valid even if the
MOUSE BUTTON ACTION has set the buttons to act like part of the keyboard.
If the accumulated motion before the report packet is generated exceeds the
+127...-128 range, the motion is broken into multiple packets.
Note that the sign of the delta y reported is a function of the Y origin
selected.

4.2 Absolute Position reporting

The ikbd can also maintain absolute mouse position. Commands exist for
resetting the mouse position, setting X/Y scaling, and interrogating the
current mouse position.

4.3 Mouse Cursor Key Mode

The ikbd can translate mouse motion into the equivalent cursor keystrokes.
The number of mouse clicks per keystroke is independently programmable in
each axis. The ikbd internally maintains mouse motion information to the
highest resolution available, and merely generates a pair of cursor key events
for each multiple of the scale factor.
Mouse motion produces the cursor key make code immediately followed by the
break code for the appropriate cursor key. The mouse buttons produce scan
codes above those normally assigned for the largest envisioned keyboard (i.e.
LEFT=0x74 & RIGHT=0x75).

5. Joystick

5.1 Joystick Event Reporting

In this mode, the ikbd generates a record whenever the joystick position is
changed (i.e. for each opening or closing of a joystick switch or trigger).

The joystick event record is two bytes of the form:
    %1111111x           ; Joystick event marker
                        ; where x is Joystick 0 or 1
    %x000yyyy           ; where yyyy is the stick position
                        ; and x is the trigger

5.2 Joystick Interrogation

The current state of the joystick ports may be interrogated at any time in
this mode by sending an 'Interrogate Joystick' command to the ikbd.

The ikbd response to joystick interrogation is a three byte report of the form
    0xFD                ; joystick report header
    %x000yyyy           ; Joystick 0
    %x000yyyy           ; Joystick 1
                        ; where x is the trigger
                        ; and yyy is the stick position

5.3 Joystick Monitoring

A mode is available that devotes nearly all of the keyboard communications
time to reporting the state of the joystick ports at a user specifiable rate.
It remains in this mode until reset or commanded into another mode. The PAUSE
command in this mode not only stop the output but also temporarily stops
scanning the joysticks (samples are not queued).

5.4 Fire Button Monitoring

A mode is provided to permit monitoring a single input bit at a high rate. In
this mode the ikbd monitors the state of the Joystick 1 fire button at the
maximum rate permitted by the serial communication channel. The data is packed
8 bits per byte for transmission to the host. The ikbd remains in this mode
until reset or commanded into another mode. The PAUSE command in this mode not
only stops the output but also temporarily stops scanning the button (samples
are not queued).

5.5 Joystick Key Code Mode

The ikbd may be commanded to translate the use of either joystick into the
equivalent cursor control keystroke(s). The ikbd provides a single breakpoint
velocity joystick cursor.
Joystick events produce the make code, immediately followed by the break code
for the appropriate cursor motion keys. The trigger or fire buttons of the
joysticks produce pseudo key scan codes above those used by the largest key
matrix envisioned (i.e. JOYSTICK0=0x74, JOYSTICK1=0x75).

6. Time-of-Day Clock

The ikbd also maintains a time-of-day clock for the system. Commands are
available to set and interrogate the timer-of-day clock. Time-keeping is
maintained down to a resolution of one second.

7. Status Inquiries

The current state of ikbd modes and parameters may be found by sending status
inquiry commands that correspond to the ikbd set commands.

8. Power-Up Mode

The keyboard controller will perform a simple self-test on power-up to detect
major controller faults (ROM checksum and RAM test) and such things as stuck
keys. Any keys down at power-up are presumed to be stuck, and their BREAK
(sic) code is returned (which without the preceding MAKE code is a flag for a
keyboard error). If the controller self-test completes without error, the code
0xF0 is returned. (This code will be used to indicate the version/release of
the ikbd controller. The first release of the ikbd is version 0xF0, should
there be a second release it will be 0xF1, and so on.)
The ikbd defaults to a mouse position reporting with threshold of 1 unit in
either axis and the Y=0 origin at the top of the screen, and joystick event
reporting mode for joystick 1, with both buttons being logically assigned to
the mouse. After any joystick command, the ikbd assumes that joysticks are
connected to both Joystick0 and Joystick1. Any mouse command (except MOUSE
DISABLE) then causes port 0 to again be scanned as if it were a mouse, and
both buttons are logically connected to it. If a mouse disable command is
received while port 0 is presumed to be a mouse, the button is logically
assigned to Joystick1 (until the mouse is reenabled by another mouse command).

9. ikbd Command Set

This section contains a list of commands that can be sent to the ikbd. Command
codes (such as 0x00) which are not specified should perform no operation
(NOPs).

9.1 RESET

    0x80
    0x01

N.B. The RESET command is the only two byte command understood by the ikbd.
Any byte following an 0x80 command byte other than 0x01 is ignored (and causes
the 0x80 to be ignored).
A reset may also be caused by sending a break lasting at least 200mS to the
ikbd.
Executing the RESET command returns the keyboard to its default (power-up)
mode and parameter settings. It does not affect the time-of-day clock.
The RESET command or function causes the ikbd to perform a simple self-test.
If the test is successful, the ikbd will send the code of 0xF0 within 300mS
of receipt of the RESET command (or the end of the break, or power-up). The
ikbd will then scan the key matrix for any stuck (closed) keys. Any keys found
closed will cause the break scan code to be generated (the break code arriving
without being preceded by the make code is a flag for a key matrix error).

9.2. SET MOUSE BUTTON ACTION

    0x07
    %00000mss           ; mouse button action
                        ;       (m is presumed = 1 when in MOUSE KEYCODE mode)
                        ; mss=0xy, mouse button press or release causes mouse
                        ;  position report
                        ;  where y=1, mouse key press causes absolute report
                        ;  and x=1, mouse key release causes absolute report
                        ; mss=100, mouse buttons act like keys 

This command sets how the ikbd should treat the buttons on the mouse. The
default mouse button action mode is %00000000, the buttons are treated as part
of the mouse logically.
When buttons act like keys, LEFT=0x74 & RIGHT=0x75.

9.3 SET RELATIVE MOUSE POSITION REPORTING

    0x08

Set relative mouse position reporting. (DEFAULT) Mouse position packets are
generated asynchronously by the ikbd whenever motion exceeds the setable
threshold in either axis (see SET MOUSE THRESHOLD). Depending upon the mouse
key mode, mouse position reports may also be generated when either mouse
button is pressed or released. Otherwise the mouse buttons behave as if they
were keyboard keys.

9.4 SET ABSOLUTE MOUSE POSITIONING

    0x09
    XMSB                ; X maximum (in scaled mouse clicks)
    XLSB
    YMSB                ; Y maximum (in scaled mouse clicks)
    YLSB
	
Set absolute mouse position maintenance. Resets the ikbd maintained X and Y
coordinates.
In this mode, the value of the internally maintained coordinates does NOT wrap
between 0 and large positive numbers. Excess motion below 0 is ignored. The
command sets the maximum positive value that can be attained in the scaled
coordinate system. Motion beyond that value is also ignored.

9.5 SET MOUSE KEYCODE MOSE

    0x0A
    deltax              ; distance in X clicks to return (LEFT) or (RIGHT)
    deltay              ; distance in Y clicks to return (UP) or (DOWN)

Set mouse monitoring routines to return cursor motion keycodes instead of
either RELATIVE or ABSOLUTE motion records. The ikbd returns the appropriate
cursor keycode after mouse travel exceeding the user specified deltas in
either axis. When the keyboard is in key scan code mode, mouse motion will
cause the make code immediately followed by the break code. Note that this
command is not affected by the mouse motion origin.

9..6 SET MOUSE THRESHOLD

    0x0B
    X                   ; x threshold in mouse ticks (positive integers)
    Y                   ; y threshold in mouse ticks (positive integers)

This command sets the threshold before a mouse event is generated. Note that
it does NOT affect the resolution of the data returned to the host. This
command is valid only in RELATIVE MOUSE POSITIONING mode. The thresholds
default to 1 at RESET (or power-up).

9.7 SET MOUSE SCALE

    0x0C
    X                   ; horizontal mouse ticks per internal X
    Y                   ; vertical mouse ticks per internal Y

This command sets the scale factor for the ABSOLUTE MOUSE POSITIONING mode.
In this mode, the specified number of mouse phase changes ('clicks') must
occur before the internally maintained coordinate is changed by one
(independently scaled for each axis). Remember that the mouse position
information is available only by interrogating the ikbd in the ABSOLUTE MOUSE
POSITIONING mode unless the ikbd has been commanded to report on button press
or release (see SET MOSE BUTTON ACTION).

9.8 INTERROGATE MOUSE POSITION

    0x0D
    Returns:
            0xF7       ; absolute mouse position header
    BUTTONS
            0000dcba   ; where a is right button down since last interrogation
                       ; b is right button up since last
                       ; c is left button down since last
                       ; d is left button up since last
            XMSB       ; X coordinate
            XLSB
            YMSB       ; Y coordinate
            YLSB

The INTERROGATE MOUSE POSITION command is valid when in the ABSOLUTE MOUSE
POSITIONING mode, regardless of the setting of the MOUSE BUTTON ACTION.

9.9 LOAD MOUSE POSITION

    0x0E
    0x00                ; filler
    XMSB                ; X coordinate
    XLSB                ; (in scaled coordinate system)
    YMSB                ; Y coordinate
    YLSB

This command allows the user to preset the internally maintained absolute
mouse position.

9.10 SET Y=0 AT BOTTOM

    0x0F

This command makes the origin of the Y axis to be at the bottom of the
logical coordinate system internal to the ikbd for all relative or absolute
mouse motion. This causes mouse motion toward the user to be negative in sign
and away from the user to be positive.

9.11 SET Y=0 AT TOP

    0x10

Makes the origin of the Y axis to be at the top of the logical coordinate
system within the ikbd for all relative or absolute mouse motion. (DEFAULT)
This causes mouse motion toward the user to be positive in sign and away from
the user to be negative.

9.12 RESUME

    0x11

Resume sending data to the host. Since any command received by the ikbd after
its output has been paused also causes an implicit RESUME this command can be
thought of as a NO OPERATION command. If this command is received by the ikbd
and it is not PAUSED, it is simply ignored.

9.13 DISABLE MOUSE

    0x12

All mouse event reporting is disabled (and scanning may be internally
disabled). Any valid mouse mode command resumes mouse motion monitoring. (The
valid mouse mode commands are SET RELATIVE MOUSE POSITION REPORTING, SET
ABSOLUTE MOUSE POSITIONING, and SET MOUSE KEYCODE MODE. )