zlnabx=zlnab211/3≤311x23_百度作业帮
zlnabx=zlnab211/3≤311x23
zlnabx=zlnab211/3≤311x23
!表示绝对值.f[x -x/2-x*x]=zlnabx=zlnab4 xy]得到f24 f_百度作业帮
zlnabx=zlnab4 xy]得到f24 f
zlnabx=zlnab4 xy]得到f24 f
向量AP=5Cosθ==-7/√10 5=√10-5
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zlnabx=zlnab109/5≤59x11
zlnabx=zlnab109/5≤59x11
∴椭圆方程/11 y9/59/10Keyboard scancodes: Keyboard scancodes
Keyboard scancodes
The data from a keyboard comes mainly in the form of scancodes,
produced by key presses or used in the protocol with the computer.
are used by the keyboard
firmware internally, and there also exist several
Here in this section we only talk about the default codes - those from
translated scancode set 2. Less common modes are discussed
Each key press and key release produces between 0 and 6 scancodes.
Key release
Below I'll only mention the scancode for key press (`make').
The scancode for key release (`break') is obtained from it
by setting the high order bit (adding 0x80 = 128).
Thus, Esc press produces scancode 01, Esc release
scancode 81 (hex).
For sequences things are similar: Keypad-/ gives e0 35
when pressed, e0 b5 when released. Most keyboards will
repeat the make code (key down code) when the key repeats. Some will also
fake Shift down and Shift up events during the repeat.
The keys PrtSc/SysRq and Pause/Break are special.
The former produces scancode e0 2a e0 37
when no modifier key is pressed simultaneously, e0 37
together with Shift or Ctrl, but 54 together with (left or right) Alt.
(And one gets the expected sequences upon release. But see
The latter produces scancode sequence
e1 1d 45 e1 9d c5
when pressed (without modifier) and nothing at all upon release.
However, together with (left or right) Ctrl, one gets
e0 46 e0 c6,
and again nothing at release. It does not repeat.
for a report on keys
with a different behaviour.
There are many reports of laptops with badly debounced key-up events.
Thus, unexpected key-up events should probably be regarded as not
unusual, and be ignored. Another source of key-up events without
preceding key-down can be the
Protocol scancodes
Most scancodes indicate a key press or release.
Some are used in the communication protocol.
Keyboard error - see ff
BAT (Basic Assurance Test) OK
Result of echo command
Some keyboards, as reply to command a4:Password not installed
Acknowledge from kbd
BAT error or Mouse transmit error
Internal failure
Keyboard fails to ack, please resend
Keyboard error
Three common causes for keyboard error are:
(i) several keys pressed simultaneously,
(ii) keyboard buffer overflow,
(iii) parity error on the serial line used by keyboard
and keyboard controller for communication.
The error reported is ff in
and 00 in scancode modes 2 and 3.
If translation is on, both 00 and ff
are translated as ff.
Usually these codes have the protocol meaning. However,
they also occur as actual scancodes, especially when
prefixed by e0.
Escape scancodes
The codes e0 and e1 introduce scancode sequences,
and are not usually used as isolated scancodes themselves
(The prefix e0 was originally used for the grey duplicates
of keys on the original PC/XT keyboard. These days e0 is
just used to expand code space. The prefix e1 used for
Pause/Break indicated that this key sends the make/break sequence
at make time, and does nothing upon release.)
This, and the above, means that the values
00, 60, 61, 6e, 71,
7a, 7c, 7e, 7f
are unavailable to signify key presses (on a default keyboard).
Nevertheless they also occur as scancodes, see for example the
keyboards below.
Also other prefixes occur, see
uses an e2 prefix
for the codes sent by a pointing device integrated on the keyboard.
Ordinary scancodes
The scancodes in translated scancode set 2 are given in hex.
Between parentheses the keycap on a US keyboard.
The scancodes are given in order, grouped according
to groups of keys that are usually found next to each other.
00 is normally an error code
02 (1!), 03 (2@), 04 (3#), 05 (4$),
06 (5%E), 07 (6^), 08 (7&),
09 (8*), 0a (9(), 0b (0)), 0c (-_),
0d (=+), 0e (Backspace)
0f (Tab), 10 (Q), 11 (W), 12 (E),
13 (R), 14 (T), 15 (Y),
16 (U), 17 (I), 18 (O),
19 (P), 1a ([{), 1b (]})
1c (Enter)
1d (LCtrl)
1e (A), 1f (S), 20 (D), 21 (F),
22 (G), 23 (H), 24 (J), 25 (K),
26 (L), 27 (;:), 28 ('")
2a (LShift)
2b (\|), on a 102-key keyboard
2c (Z), 2d (X), 2e (C), 2f (V),
30 (B), 31 (N), 32 (M), 33 (,&),
34 (.&), 35 (/?), 36 (RShift)
37 (Keypad-*) or (*/PrtScn) on a 83/84-key keyboard
38 (LAlt), 39 (Space bar),
3a (CapsLock)
3b (F1), 3c (F2), 3d (F3), 3e (F4),
3f (F5), 40 (F6), 41 (F7),
42 (F8), 43 (F9), 44 (F10)
45 (NumLock)
46 (ScrollLock)
47 (Keypad-7/Home), 48 (Keypad-8/Up),
49 (Keypad-9/PgUp)
4a (Keypad--)
4b (Keypad-4/Left), 4c (Keypad-5),
4d (Keypad-6/Right), 4e (Keypad-+)
4f (Keypad-1/End), 50 (Keypad-2/Down),
51 (Keypad-3/PgDn)
52 (Keypad-0/Ins), 53 (Keypad-./Del)
54 (Alt-SysRq) on a 84+ key keyboard
55 occurs e.g. as F11 on a Cherry G80-0777 keyboard,
as F12 on a Telerate keyboard,
as PF1 on a Focus 9000 keyboard, and as FN on an IBM ThinkPad.
56 mostly on non-US keyboards. It is often an unlabelled key
of the left Alt key.
57 (F11), 58 (F12) both on a 101+ key keyboard
59-5a-...-7f are less common.
Assignment is essentially random.
Scancodes 55-59 occur as F11-F15 on the
Scancodes 59-5c occur on the
X calls 5d `KEY_Begin'.
Scancodes 61-64 occur on a
Scancodes 55, 6d, 6f, 73, 74,
77, 78, 79, 7a, 7b,
7c, 7e occur on the
Scancodes 65, 67, 69, 6b
occur on a
Scancodes 66-68, 73 occur on the
Scancodes 70, 73, 79, 7b, 7d
occur on a
Scancodes f1 and f2 occur on
Escaped scancodes
Apart from the Pause/Break key, that has an escaped sequence starting
with e1, the escape used is e0. Often, the codes
are chosen in such a way that something meaningful happens when
the receiver just discards the e0.
e0 1c (Keypad Enter)
1c (Enter)
e0 1d (RCtrl)
1d (LCtrl)
e0 2a (fake LShift)
2a (LShift)
e0 35 (Keypad-/)
e0 36 (fake RShift)
36 (RShift)
e0 37 (Ctrl-PrtScn)
37 (*/PrtScn)
e0 38 (RAlt)
e0 46 (Ctrl-Break)
46 (ScrollLock)
e0 47 (Grey Home)
47 (Keypad-7/Home)
e0 48 (Grey Up)
48 (Keypad-8/UpArrow)
e0 49 (Grey PgUp)
49 (Keypad-9/PgUp)
e0 4b (Grey Left)
4b (Keypad-4/Left)
e0 4d (Grey Right)
4d (Keypad-6/Right)
e0 4f (Grey End)
4f (Keypad-1/End)
e0 50 (Grey Down)
50 (Keypad-2/DownArrow)
e0 51 (Grey PgDn)
51 (Keypad-3/PgDn)
e0 52 (Grey Insert)
52 (Keypad-0/Ins)
e0 53 (Grey Delete)
53 (Keypad-./Del)
These escaped scancodes occur only on 101+ key keyboards.
e0 5b (LeftWindow)
e0 5c (RightWindow)
e0 5d (Menu)
Other escaped scancodes occur - see below under the individual keyboards.
Fake shifts
The ten grey keys Insert, Home, PgUp, Delete, End, PgDn,
Up, Left, Down, Right are supposed to function regardless
of the state of Shift and NumLock keys. But for an old AT keyboard
the keypad keys would produce digits when Numlock was on or Shift
was down. Therefore, in order to fool old programs,
fake scancodes are sent: when LShift is down, and Insert is
pressed, e0 aa e0 52
upon release of Insert e0 d2 e0 2a
is sent. In other words, a fake LShift-up and
fake LShift-down are inserted.
If the Shift key is released earlier than the repeated key,
then a real Shift-up code occurs (without preceding fake Shift-down)
so that a program ignoring e0 would see one more Shift-up
than Shift-down.
When NumLock is on, no fake Shifts are sent when Shift was down,
but fake Shifts are sent when Shift was not down. Thus,
with Numlock, if Insert is pressed,
e0 2a e0 52 is sent
and upon release e0 d2 e0 aa is sent.
The keyboard maintains a private NumLock mode, toggled when
NumLock is pressed, and set when the NumLock LED is set.
In the same way, when Shift is down, the Grey-/ key produces
fake Shift-up and fake Shift-down sequences. However, it does
not react to the state of NumLock. The purpose of course is to
fool programs that identify Grey-/ with ordinary /, so that they
don't treat Shift-Grey-/ like Shift-/, i.e., ?.
On a Toshiba notebook, the three Windows keys are treated like
the group of ten keys mentioned, and get fake shifts when
(left or right) Shift is down. They do not react to NumLock.
Added non-fake shifts
On my 121-key
keyboard there are
function keys F1, ..., F24, where F1, ..., F12 send the expected codes
3b, ..., 58, and F13, ..., F24 send the same codes
together with the LShift code 2a.
Thus, F13 gives 2a 3b on press,
and bb aa on release.
Similarly, there are keys with added LCtrl code 1d.
But there are also keys with added fake shifts e0 2a.
reports that the "Preh Commander AT" keyboard with additional F11-F22 keys
treats F11-F20 as Shift-F1..Shift-F10 and F21/F22 as Ctrl-F1/Ctrl-F2; the
Eagle PC-2 keyboard with F11-F24 keys treats those additional keys
in the same way.
Turbo Mode
On some motherboards the LCtrl-LAlt-GreyPlus and LCtrl-LAlt-GreyMinus
switch Turbo mode on/off, respectively. For these, the motherboard
may generate the same scancode sequence when the Turbo button is
pushed: Turbo Switch (High->Low):
1d 38 4a ce b8 9d
and Turbo Switch (Low->High):
1d 38 4e ce b8 9d.
Other peculiar combinations in this style include
LCtrl-LAlt-LShift-GreyMinus and LCtrl-LAlt-LShift-GreyPlus to turn
system cache off/on.
If Green PC system power saving mode is enabled in AMIBIOS Setup,
the AMI MegaKey keyboard controller recognizes the combinations
Ctrl-Alt-\ (put the system into immediate power down mode),
Ctrl-Alt-[ (disable the Green PC power savings mode temporarily),
Ctrl-Alt-] (enables the Green PC power down mode).
Thio Yu Jin && complains that on his Toshiba 4010CDS
the Ctrl-Alt-Shift-T key combination brings up the Toshiba user manual.
(04 Mar 1999 - not April 1.)
Power Saving
recommends: "i8042-based keyboards should deploy the
following scan codes for power management buttons, i.e., POWER and SLEEP
Set-1 make/break
Set-2 make/break
e0 5e / e0 de e0 37 / e0 f0 37
e0 5f / e0 df e0 3f / e0 f0 3f
e0 63 / e0 e3 e0 5e / e0 f0 5e
The Power, Sleep, and Wake event scan codes are the i8042 equivalents
to the System Power Down, System Sleep, and System Wake Up HID usages".
Many keyboards have Power/Sleep/Wake keys that have to be
activated by a fourth key (unlabeled, or labeled FN): pressing
one of these four keys does not produce any scancodes, but
when the FN key is pressed simultaneously, the Power/Sleep/Wake
keys give the codes listed above.
Initializing special keyboards
Many keyboards have more keys and buttons than the standard ones.
Sometimes these additional keys produce scancode combinations
that were unused before. But on other keyboard such additional
keys do not produce any code at all, until some initializing
action is taken.
Sometimes that action consists of writing some bytes to keyboard
registers. See, for example, the
Manipulating extra LEDs
Some keyboards have additional LEDs, and in a few cases we know
how to manipulate those.
needs command sequences
eb 00 xy, with
xy = 01 for the Moon LED and
xy = 02 for the zzZ LED.
command sequences eb 00 xy, with
xy = 01 for the Msg LED,
xy = 02 for the CD LED,
xy = 04 for the Power LED,
xy = 10 for the Talk LED, and
xy = 20 for the Message Waiting LED.
command sequences eb 00 xy, with
xy = 04 for the Suspend LED and
xy = 20 for the Mute LED.
the command sequences eb 71 and eb 70
to switch the Standby LED on and off.
has an additional amber LED. It is turned on by sending eb,
and then blinks about once a second. It is turned off again by ec.
The laptop FN key
Laptops have no room for all nonsensical keys one usually find
on a regular keyboard. So, the number pad and other keys are
folded into the main part of the keyboard. A key without label,
or labelled FN is often used to modify the meaning of other keys.
This FN does not produce scancodes itself, it only modifies the
scancodes produced by other keys.
Neil Brown reports about his Dell Latitude D800 laptop that it has
five key combinations that do not produce proper break codes.
The five combinations FN+F2, FN+F3, FN+F10, FN+Down, FN+Up
(labelled Wireless, Brighter, Darker, Battery, CDEject)
produce make codes e0 08, e0 07,
e0 09, e0 05, e0 06,
respectively. The first three do not produce any break code.
The last two have a break code that is identical to the make code.zlnabx=zlnab4 xy]得到f24 f_百度知道
zlnabx=zlnab4 xy]得到f24 f
向量AP=5Cosθ==-7/√10 5=√10-5
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