149 lines
5.0 KiB
Groff
149 lines
5.0 KiB
Groff
.\"
|
||
.\" $Id: keyboard.4,v 1.14 1998/06/08 06:11:59 jkoshy Exp $
|
||
.\"
|
||
.Dd January 8, 1995
|
||
.Dt KEYBOARD 4 i386
|
||
.Os FreeBSD
|
||
.Sh NAME
|
||
.Nm keyboard
|
||
.Nd pc keyboard interface
|
||
.Sh DESCRIPTION
|
||
|
||
The PC keyboard is used as the console character input device. The keyboard
|
||
is owned by the current virtual console.
|
||
To switch between the virtual consoles use the sequence
|
||
.Ar ALT+Fn
|
||
, which means hold down ALT and press one of the function keys. The
|
||
virtual console with the same number as the function key is then
|
||
selected as the current virtual console and given exclusive use of
|
||
the keyboard and display.
|
||
|
||
The console allows entering values that are not physically
|
||
present on the keyboard via a special keysequence.
|
||
To use this facility press and hold down ALT,
|
||
then enter a decimal number from 0-255 via the numerical keypad, then
|
||
release ALT. The entered value is then used as the ASCII value for one
|
||
character. This way it is possible to enter any ASCII value, not present
|
||
on the keyboard.
|
||
The console driver also includes a history function. It is activated by
|
||
pressing the scroll-lock key. This holds the display, and enables the cursor
|
||
arrows for scrolling up and down through the last scrolled out lines.
|
||
|
||
The keyboard is configurable to suit the individual user and the different
|
||
national layout.
|
||
|
||
The keys on the keyboard can have any of the following functions:
|
||
|
||
Normal key - Enter the ASCII value associated with the key.
|
||
|
||
Function key - Enter a string of ASCII values.
|
||
|
||
Switch Key - Switch virtual console.
|
||
|
||
Modifier Key - Change the meaning of another key.
|
||
|
||
|
||
The keyboard is seen as a number of keys numbered from 1 to n. This
|
||
number is often referred to as the "scancode" for a given key. The number
|
||
of the key is transmitted as an 8 bit char with bit 7 as 0 when a key is
|
||
pressed, and the number with bit 7 as 1 when released. This makes it
|
||
possible to make the mapping of the keys fully configurable.
|
||
|
||
The meaning of every key is programmable via the PIO_KEYMAP ioctl call, that
|
||
takes a structure keymap_t as argument. The layout of this structure is as
|
||
follows:
|
||
.Pp
|
||
.Bd -literal -offset indent
|
||
struct keymap {
|
||
u_short n_keys;
|
||
struct key_t {
|
||
u_char map[NUM_STATES];
|
||
u_char spcl;
|
||
u_char flgs;
|
||
} key[NUM_KEYS];
|
||
};
|
||
.Ed
|
||
.Pp
|
||
The field n_keys tells the system how many keydefinitions (scancodes)
|
||
follows. Each scancode is then specified in the key_t substructure.
|
||
|
||
Each scancode can be translated to any of 8 different values, depending
|
||
on the shift, control, and alt state. These eight possibilities are
|
||
represented by the map array, as shown below:
|
||
|
||
alt
|
||
scan cntrl alt alt cntrl
|
||
code base shift cntrl shift alt shift cntrl shift
|
||
map[n] 0 1 2 3 4 5 6 7
|
||
---- ------------------------------------------------------
|
||
0x1E 'a' 'A' 0x01 0x01 'a' 'A' 0x01 0x01
|
||
|
||
This is the default mapping for the key labelled 'A' which normally has
|
||
scancode 0x1E. The eight states are as shown, giving the 'A' key its
|
||
normal behavior.
|
||
The spcl field is used to give the key "special" treatment, and is
|
||
interpreted as follows.
|
||
Each bit corresponds to one of the states above. If the bit is 0 the
|
||
key emits the number defined in the corresponding map[] entry.
|
||
If the bit is 1 the key is "special". This means it does not emit
|
||
anything; instead it changes the "state". That means it is a shift,
|
||
control, alt, lock, switch-screen, function-key or no-op key.
|
||
The bitmap is backwards ie. 7 for base, 6 for shift etc.
|
||
|
||
The flgs field defines if the key should react on caps-lock (1),
|
||
num-lock (2), both (3) or ignore both (0).
|
||
|
||
The kbdcontrol utility is used to load such a description into/outof
|
||
the kernel at runtime. This makes it possible to change the key
|
||
assignments at runtime, or more important to get (GIO_KEYMAP ioctl)
|
||
the exact key meanings from the kernel (fx. used by the X server).
|
||
|
||
The function keys can be programmed using the SETFKEY ioctl call.
|
||
|
||
This ioctl takes a argument of the type fkeyarg_t:
|
||
.Bd -literal -offset indent
|
||
struct fkeyarg {
|
||
u_short keynum;
|
||
char keydef[MAXFK];
|
||
char flen;
|
||
};
|
||
.Ed
|
||
.Pp
|
||
The field keynum defines which function key that is programmed.
|
||
The array keydef should contain the new string to be used (MAXFK long),
|
||
and the length should be entered in flen.
|
||
|
||
The GETFKEY ioctl call works in a similar manner, except it returns
|
||
the current setting of keynum.
|
||
|
||
The function keys are numbered like this:
|
||
.Bd -literal -offset indent
|
||
F1-F12 key 1 - 12
|
||
Shift F1-F12 key 13 - 24
|
||
Ctrl F1-F12 key 25 - 36
|
||
Ctrl+shift F1-F12 key 37 - 48
|
||
|
||
Home key 49
|
||
Up arrow key 50
|
||
Page Up key 51
|
||
(keypad) - key 52
|
||
Left arrow key 53
|
||
(keypad) 5 key 54
|
||
Right arrow key 55
|
||
(keypad) + key 56
|
||
End key 57
|
||
Down arrow key 58
|
||
Page down key 59
|
||
Insert key 60
|
||
Delete key 61
|
||
|
||
Right window key 62
|
||
Left window key 63
|
||
Menu key 64
|
||
.Ed
|
||
|
||
The kbdcontrol utility also allows changing these values at runtime.
|
||
.Pp
|
||
.Sh AUTHORS
|
||
.An S<EFBFBD>ren Schmidt Aq sos@FreeBSD.org
|