1.\" 2.Dd January 8, 1995 3.Dt KEYBOARD 4 4.Os 5.Sh NAME 6.Nm keyboard 7.Nd pc keyboard interface 8.Sh DESCRIPTION 9The PC keyboard is used as the console character input device. 10The keyboard 11is owned by the current virtual console. 12To switch between the virtual consoles use the sequence 13.Ar ALT+Fn , 14which means hold down ALT and press one of the function keys. 15The 16virtual console with the same number as the function key is then 17selected as the current virtual console and given exclusive use of 18the keyboard and display. 19.Pp 20The console allows entering values that are not physically 21present on the keyboard via a special keysequence. 22To use this facility press and hold down ALT, 23then enter a decimal number from 0-255 via the numerical keypad, then 24release ALT. 25The entered value is then used as the ASCII value for one 26character. 27This way it is possible to enter any ASCII value, not present 28on the keyboard. 29The console driver also includes a history function. 30It is activated by 31pressing the scroll-lock key. 32This holds the display, and enables the cursor 33arrows for scrolling up and down through the last scrolled out lines. 34.Pp 35The keyboard is configurable to suit the individual user and the different 36national layout. 37.Pp 38The keys on the keyboard can have any of the following functions: 39.Pp 40.Bl -tag -width "Modifier Key" -compact 41.It "Normal key" 42Enter the ASCII value associated with the key. 43.It "Function key" 44Enter a string of ASCII values. 45.It "Switch Key" 46Switch virtual console. 47.It "Modifier Key" 48Change the meaning of another key. 49.El 50.Pp 51The keyboard is seen as a number of keys numbered from 1 to n. 52This 53number is often referred to as the "scancode" for a given key. 54The number 55of the key is transmitted as an 8 bit char with bit 7 as 0 when a key is 56pressed, and the number with bit 7 as 1 when released. 57This makes it 58possible to make the mapping of the keys fully configurable. 59.Pp 60The meaning of every key is programmable via the PIO_KEYMAP ioctl call, that 61takes a structure keymap_t as argument. 62The layout of this structure is as 63follows: 64.Bd -literal -offset indent 65 struct keymap { 66 u_short n_keys; 67 struct key_t { 68 u_char map[NUM_STATES]; 69 u_char spcl; 70 u_char flgs; 71 } key[NUM_KEYS]; 72 }; 73.Ed 74.Pp 75The field n_keys tells the system how many keydefinitions (scancodes) 76follows. 77Each scancode is then specified in the key_t substructure. 78.Pp 79Each scancode can be translated to any of 8 different values, depending 80on the shift, control, and alt state. 81These eight possibilities are 82represented by the map array, as shown below: 83.Bd -literal 84 alt 85 scan cntrl alt alt cntrl 86 code base shift cntrl shift alt shift cntrl shift 87 map[n] 0 1 2 3 4 5 6 7 88 ---- ------------------------------------------------------ 89 0x1E 'a' 'A' 0x01 0x01 'a' 'A' 0x01 0x01 90.Ed 91.Pp 92This is the default mapping for the key labelled 'A' which normally has 93scancode 0x1E. 94The eight states are as shown, giving the 'A' key its 95normal behavior. 96The spcl field is used to give the key "special" treatment, and is 97interpreted as follows. 98Each bit corresponds to one of the states above. 99If the bit is 0 the 100key emits the number defined in the corresponding map[] entry. 101If the bit is 1 the key is "special". 102This means it does not emit 103anything; instead it changes the "state". 104That means it is a shift, 105control, alt, lock, switch-screen, function-key or no-op key. 106The bitmap is backwards i.e., 1077 for base, 6 for shift etc. 108.Pp 109The flgs field defines if the key should react on caps-lock (1), 110num-lock (2), both (3) or ignore both (0). 111.Pp 112The 113.Xr kbdcontrol 1 114utility is used to load such a description into/outof 115the kernel at runtime. 116This makes it possible to change the key 117assignments at runtime, or more important to get (GIO_KEYMAP ioctl) 118the exact key meanings from the kernel (e.g.\& used by the X server). 119.Pp 120The function keys can be programmed using the SETFKEY ioctl call. 121.Pp 122This ioctl takes an argument of the type fkeyarg_t: 123.Bd -literal -offset indent 124 struct fkeyarg { 125 u_short keynum; 126 char keydef[MAXFK]; 127 char flen; 128 }; 129.Ed 130.Pp 131The field keynum defines which function key that is programmed. 132The array keydef should contain the new string to be used (MAXFK long), 133and the length should be entered in flen. 134.Pp 135The GETFKEY ioctl call works in a similar manner, except it returns 136the current setting of keynum. 137.Pp 138The function keys are numbered like this: 139.Bd -literal -offset indent 140 F1-F12 key 1 - 12 141 Shift F1-F12 key 13 - 24 142 Ctrl F1-F12 key 25 - 36 143 Ctrl+shift F1-F12 key 37 - 48 144 145 Home key 49 146 Up arrow key 50 147 Page Up key 51 148 (keypad) - key 52 149 Left arrow key 53 150 (keypad) 5 key 54 151 Right arrow key 55 152 (keypad) + key 56 153 End key 57 154 Down arrow key 58 155 Page down key 59 156 Insert key 60 157 Delete key 61 158 159 Left window key 62 160 Right window key 63 161 Menu key 64 162.Ed 163.Pp 164The 165.Xr kbdcontrol 1 166utility also allows changing these values at runtime. 167.Sh AUTHORS 168.An S\(/oren Schmidt Aq Mt sos@FreeBSD.org 169