================================================================
IBM PC KEYBOARD INFORMATION FOR SOFTWARE DEVELOPERS
================================================================
Your host: Chris Giese
http://www.execpc.com/~geezer/os
Distribute freely. Last revised on Jan 3, 2002
Sources:
PORTS.A of Ralf Brown's interrupt list collection
repairfaq.org keyboard FAQ(doesn't appear to exsist)
Linux source code
Test hardware:
New Samsung KB3T001SAXAA 104-key keyboard
Old Maxi 2186035-00-21 101-key keyboard
NO WARRANTY. NO GUARANTEE. I have tried to make this information
accurate. I don't know if I succeeded. Corrections or additional
information would be welcome.
This is a plain-text document. If you use a word-processor to view
it, use a fixed-pitch font (like Courier) so columnar data and
ASCII art lines up properly.
Lessons learned:
- Both the 8048 MCU in the keyboard and the 8042 controller
on the motherboard accept command bytes.
- There is a bit (KCC) in the poorly-named "Command Byte" which
seems to enable AT-to-XT scancode conversion (scancode set 2
to scancode set 1). After booting DOS, my keyboard uses
scancode set 2 with this conversion bit turned on. If I turn
the bit off and switch to scancode set 1, operation remains
the same.
- Scancode set 3 is probably the most elegant, in that it returns
a one-byte make code for _every_ key. Unfortunately, not all
keyboards support it.
- The scancodes of some keys depend on the internal num lock state
of the keyboard.
================================================================
KEYBOARD I/O REGISTERS ON THE PC
================================================================
60h data
64h command (write)
64h Status (read)
Bits in Status register (names from Linux source)
b7 PERR parity error in data received from keyboard
b6 GTO receive timeout
b5 transmit timeout (or PS/2 mouse?)
b4 keyboard is locked
b3 0=60h was the port last accessed, 1=61h was last (?)
b2 System Flag status: 0=power-up/reset, 1=selftest OK (?)
b1 IBF input buffer full (data from host to keyboard)
b0 OBF output buffer full (data from keyboard to host)
Bits in Output Port of 8042 chip (Table P0383 in PORTS.A)
The Output Port is written by controller command D1h,
and read by controller command D0h
b7 keyboard data output
b6 keyboard clock output
b5 input buffer NOT full
b4 output buffer NOT empty
b3 (varies)
b2 (varies)
b1 A20 gate
b0 system reset (THIS BIT SHOULD ALWAYS BE SET TO 1)
Bits in Input Port of 8042 chip
The Input Port is read by controller command C0h
b7 keyboard NOT locked
b6-b0 (varies)
Bits in "Command Byte" (confusing name; from Table P0404 in PORTS.A)
The "Command Byte" is written by controller command 60h
and read by controller command 20h
(names from Linux source)
b7 (reserved)
b6 KCC convert set 2 scancodes to set 1 ("IBM PC compatibility mode")
b5 DMS disables PS/2 mouse when set
b4 disables keyboard when set
b3 ignore keyboard lock switch when set
b2 SYS System Flag (same as b2 in Status register, it seems)
b1 enables IRQ12 from PS/2 mouse when set
b0 EKI enables IRQ1 on keyboard output buffer full
Result Byte for interface self-tests (Table P0406 in PORTS.A)
Returned by controller commands A9h or ABh
0 no error
1 clock line stuck low
2 clock line stuck high
3 data line stuck low
4 data line stuck high
================================================================
CONTROLLER COMMANDS (from Table P0401 of PORTS.A)
================================================================
Before writing each byte of these commands to port 64h,
poll the status register (port 60h) until bit b1=0.
20h-2Fh reads byte with address=lower 5 bits of command
The byte at address 0 is the "Command Byte".
60h-7Fh nn writes byte nn to address=lower 5 bits of command
The byte at address 0 is the "Command Byte".
A7h disables PS/2 mouse port (MCA only?)
A8h enables PS/2 mouse port (MCA only?)
A9h self-test mouse interface, returns Result Byte (see above)
AAh self-test controller; returns 55h if success, FCh if failure
ABh self-test keyboard interface, returns Result Byte (see above)
ADh disables keyboard (sets b4 of "Command Byte")
AEh enables keyboard (clears b4 of "Command Byte")
C0h reads Input Port
D0h reads Output Port
D1h nn writes Output Port
Important: bit 0 (system reset) should always be set here,
as the system may hang constantly. To reset the PC, pulse
b0 of the Output Port with command FEh instead.
DDh disable A20 (Not all systems support this byte)
DFh enable A20 (Not all systems support this byte)
E0h read test inputs. return value=
b1 kbd data
b0 kbd clock
EDh nn write LEDs. nn=
b2 Caps Lock
b1 Num Lock
b0 Scroll Lock
F0h-FFh pulse bit(s) of Output Port low for 6 microseconds.
If b0-b3 of the command is low, the corresponding bit
in the Output Port will be pulsed low. b0=system reset,
and should ALWAYS be PULSED low, never set low constantly.
================================================================
KEYBOARD COMMANDS (from Table P0386 of PORTS.A)
================================================================
Before writing each byte of these commands to port 60h,
poll the status register (port 60h) until bit b1=0.
Unless otherwise noted: each command responds with FAh (ACKnowledge)
or FEh (Resend) after receiving each byte of the command.
EDh nn write LEDs, as above
EEh echo, keyboard responds with EEh
EFh no-operation (reserved)
F0h nn selects scancode set nn=1-3 or 0 to return current set
F2h read ID. Keyboard responds with ACK (FAh) and two optional
ID bytes:
(none) AT keyboard
83h ABh (?)
ABh 41h MF2, translation mode
ABh 83h MF2, pass-through mode
F3h nn set typematic (auto-repeat) rate/delay. nn=
b7 unused
b6..5 Repeat delay (00=250 msec ... 11=1000msec)
b4..0 Repeat rate (00000=30 Hz ... 11111=2 Hz).
F4h clears output buffer, enables keyboard
F5h disables keyboard, resets to defaults
F6h sets keyboard defaults
F7h make all keys typematic (auto-repeat) [*]
F8h make all keys make-break [*]
F9h make all keys make-only [*]
FAh make all keys typematic and make-break [*]
FBh nn make one key typematic [*]
FCh nn make one key make-break [*]
FDh nn make one key make-only [*]
[*] these commands may work only for
scancode set 3; I'm not sure.
FEh resend previous scan code
FFh reset keyboard CPU, do power-on self-test, return
self-test result byte
non-key status bytes
--------------------
00h Key detection error or buffer full.
AAh Power-on/reset diagnostics successful.
E0h (scancode sets 1 and 2) Prefix byte for "gray" keys
(keys not on original 83-/84-key keyboard)
EEh Sent in response to ECHO command.
F0h (scancode sets 2 and 3) Prefix byte for break codes.
FAh ACKknowledge; response to most commands.
FCh Diagnostics failed (MF keyboard).
FDh Diagnostics failed (AT keyboard).
The keyboard stops scanning and waits for next command
after returning code FCh or FDh
FEh Last command was invalid or had parity error; resend it.
FFh Key detection error or buffer full.
====================================================================
SCANCODES FOR SCANCODE SET 1 (XT)
====================================================================
US 104-key keyboard, set 1 scancodes
"Make" code is generated when key is pressed.
"Break" code is generated when key is released.
Hex value of make code for each key is shown.
Most keys:
one-byte make code = nn
one-byte repeat code = nn
one-byte break code = 80h + nn
"Gray" keys (not on original 84-key keyboard):
two-byte make code = E0nn
two-byte repeat code = E0nn
two-byte break code = E0 followed by 80h + nn
"Gray" keys noted by [1] are NumLock-sensitive.
When the keyboard's internal NumLock is active:
four-byte make code = E02AE0nn
two-byte repeat code = E0nn
four-byte break code = E0 followed by 80h + nn followed by E0AA
____ ___________________ ___________________ ___________________
| | | | | | | | | | | | | | | | |
|Esc | |F1 |F2 |F3 |F4 | |F5 |F6 |F7 |F8 | |F9 |F10 |F11 |F12 |
| | | | | | | | | | | | | | | | |
| 01| | 3B| 3C| 3D| 3E| | 3F| 40| 41| 42| | 43| 44| 57| 58|
|____| |____|____|____|____| |____|____|____|____| |____|____|____|____|
__________________________________________________________________________
| | | | | | | | | | | | | | | |
|~ |! |@ |# |$ |% |^ |& |* |( |) |_ |+ || |bksp|
|` |1 |2 |3 |4 |5 |6 |7 |8 |9 |0 |- |= |\ | |
| 29| 02| 03| 04| 05| 06| 07| 08| 09| 0A| 0B| 0C| 0D| 2B| 0E|
|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|
| | | | | | | | | | | | | | |
|Tab |Q |W |E |R |T |Y |U |I |O |P |{ |} | |
| | | | | | | | | | | |[ |] | |
| 0F| 10| 11| 12| 13| 14| 15| 16| 17| 18| 19| 1A| 1B| |
|____|____|____|____|____|____|____|____|____|____|____|____|____| |
| | | | | | | | | | | | | |
|Caps|A |S |D |F |G |H |J |K |L |: |" | Enter |
| | | | | | | | | | |; |' | |
| 3A| 1E| 1F| 20| 21| 22| 23| 24| 25| 26| 27| 28| 1C|
|____|____|____|____|____|____|____|____|____|____|____|____|______________|
| | | | | | | | | | | | |
| L Shift |Z |X |C |V |B |N |M |< |> |? | R Shift |
| | | | | | | | |, |. |/ | |
| 2A| 2C| 2D| 2E| 2F| 30| 31| 32| 33| 34| 35| 36|
|_________|____|____|____|____|____|____|____|____|____|____|______________|
| | | | | | | | |
|L Ctrl | L win | L Alt | space | R Alt | R win | menu |R Ctrl |
| |[1] | | | |[1] |[1] | |
| 1D| E05B| 38| 39| E038| E05C| E05D| E01D|
|_______|_______|_______|__________________|_______|_______|_______|_______|
[2] For PrintScreen/SysRq key: make code = E02AE037,
repeat code = E037, break code = E0B7E0AA
[3] The Pause/Break key does not repeat, and it does not
generate a break code. Its make code is E11D45E19DC5
____ ____ ____
| | | |
|Prt |Scrl|Paus|
|Scrn|Lock|Brk |
| [2]| 46| [3]|
|____|____|____|
____ ____ ____ ____ ____ ____ ____
| | | | | | | | |
|Ins |Home|PgUp| |Num |/ |* |- |
|[1] |[1] |[1] | |Lock| | | |
|E052|E047|E049| | 45|E035| 37| 4A|
|____|____|____| |____|____|____|____|
| | | | | | | | |
|Del |End |PgDn| |7 |8 |9 | |
|[1] |[1] |[1] | |Home|(U) |PgUp| |
|E053|E04F|E051| | 47| 48| 49| |
|____|____|____| |____|____|____| |
| | | |+ |
|4 |5 |6 | |
|(L) | |(R) | |
| 4B| 4C| 4D| 4E|
____ |____|____|____|____|
| | | | | | |
|(U) | |1 |2 |3 | |
|[1] | |End |(D) |PgDn| |
|E048| | 4F| 50| 51|Ent |
____|____|____ |____|____|____| |
| | | | | | | |
|(L) |(D) |(R) | |0 |. | |
|[1] |[1] |[1] | |Ins |Del | |
|E04B|E050|E04D| | 52| 53|E01C|
|____|____|____| |_________|____|____|
code key code key code key code key
---- --- ---- --- ---- --- ---- ---
01 Esc 0F Tab 1D L Ctrl 2B \|
02 1! 10 Q 1E A 2C Z
03 2" 11 W 1F S 2D X
04 3# 12 E 20 D 2E C
05 4$ 13 R 21 F 2F V
06 5% 14 T 22 G 30 B
07 6^ 15 Y 23 H 31 N
08 7& 16 U 24 J 32 M
09 8* 17 I 25 K 33 ,<
0A 9( 18 O 26 L 34 .>
0B 0) 19 P 27 ;: 35 /?
0C -_ 1A [{ 28 '" 36 R Shift
0D =+ 1B ]} 29 `~ 37 *
0E BackSpace 1C Enter 2A L Shift 38 L Alt
code key code key code key code key
---- --- ---- --- ---- --- ---- ---
39 Space 41 F7 49 PageUp 9 51 PageDown 3
3A CapsLock 42 F8 4A - 52 Insert 0
3B F1 43 F9 4B (left) 4 53 Del .
3C F2 44 F10 4C 5
3D F3 45 NumLock 4D (right) 6 57 F11
3E F4 46 ScrollLock 4E + 58 F12
3F F5 47 Home 7 4F End 1
40 F6 48 (up) 8 50 (down) 2
code key
---- ---
E01C Enter (on numeric keypad)
E01D R Ctrl
E02A make code prefix for keyboard internal numlock
E02AE037 PrintScreen make code
E035 /
E037 PrintScreen repeat code
E038 R Alt
E047 Home
E048 (up)
E049 PageUp
E04B (left)
E04D (right)
E04F End
E050 (down)
E051 PageDown
E052 Insert
E053 Del
E05B L Win
E05C R Win
E05D Menu
E0AA break code suffix for keyboard internal numlock
E0B7E0AA PrintScreen break code
E11D45E19DC5 Pause
====================================================================
SCANCODES FOR SCANCODE SET 2 (AT)
====================================================================
US 104-key keyboard, set 2 scancodes,
8042 AT-to-XT scancode translation OFF
"Make" code is generated when key is pressed.
"Break" code is generated when key is released.
Hex value of make code for each key is shown.
Most keys:
one-byte make code = nn
one-byte repeat code = nn
two-byte break code = F0nn
"Gray" keys (not on original 84-key keyboard):
two-byte make code = E0nn
two-byte repeat code = E0nn
three-byte break code = E0F0nn
"Gray" keys noted by [1] are NumLock-sensitive.
When the keyboard's internal NumLock is active:
four-byte make code = E012E0nn
two-byte repeat code = E0nn
six-byte break code = E0F0nnE0F012
____ ___________________ ___________________ ___________________
| | | | | | | | | | | | | | | | |
|Esc | |F1 |F2 |F3 |F4 | |F5 |F6 |F7 |F8 | |F9 |F10 |F11 |F12 |
| | | | | | | | | | | | | | | | |
| 76| | 05| 06| 04| 0C| | 03| 0B| 83| 0A| | 01| 09| 78| 07|
|____| |____|____|____|____| |____|____|____|____| |____|____|____|____|
__________________________________________________________________________
| | | | | | | | | | | | | | | |
|~ |! |@ |# |$ |% |^ |& |* |( |) |_ |+ || |bksp|
|` |1 |2 |3 |4 |5 |6 |7 |8 |9 |0 |- |= |\ | |
| 0E| 16| 1E| 26| 25| 2E| 36| 3D| 3E| 46| 45| 4E| 55| 5D| 66|
|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|
| | | | | | | | | | | | | | |
|Tab |Q |W |E |R |T |Y |U |I |O |P |{ |} | |
| | | | | | | | | | | |[ |] | |
| 0D| 15| 1D| 24| 2D| 2C| 35| 3C| 43| 44| 4D| 54| 5B| |
|____|____|____|____|____|____|____|____|____|____|____|____|____| |
| | | | | | | | | | | | | |
|Caps|A |S |D |F |G |H |J |K |L |: |" | Enter |
| | | | | | | | | | |; |' | |
| 58| 1C| 1B| 23| 2B| 34| 33| 3B| 42| 4B| 4C| 52| 5A|
|____|____|____|____|____|____|____|____|____|____|____|____|______________|
| | | | | | | | | | | | |
| L Shift |Z |X |C |V |B |N |M |< |> |? | R Shift |
| | | | | | | | |, |. |/ | |
| 12| 1A| 22| 21| 2A| 32| 31| 3A| 41| 49| 4A| 59|
|_________|____|____|____|____|____|____|____|____|____|____|______________|
| | | | | | | | |
|L Ctrl | L win | L Alt | space | R Alt | R win | menu |R Ctrl |
| |[1] | | | |[1] |[1] | |
| 14| E01F| 11| 29| E011| E027| E02F| E014|
|_______|_______|_______|__________________|_______|_______|_______|_______|
[2] For PrintScreen/SysRq key: make code = E012E07C,
repeat code = E07C, break code = E0F07CE0F012
[3] The Pause/Break key does not repeat, and it does not
generate a break code. Its make code is E11477E1F014F077
____ ____ ____
| | | |
|Prt |Scrl|Paus|
|Scrn|Lock|Brk |
| [2]| 7E| [3]|
|____|____|____|
____ ____ ____ ____ ____ ____ ____
| | | | | | | | |
|Ins |Home|PgUp| |Num |/ |* |- |
|[1] |[1] |[1] | |Lock| | | |
|E070|E06C|E07D| | 77|E04A| 7C| 7B|
|____|____|____| |____|____|____|____|
| | | | | | | | |
|Del |End |PgDn| |7 |8 |9 | |
|[1] |[1] |[1] | |Home|(U) |PgUp| |
|E071|E069|E07A| | 6C| 75| 7D| |
|____|____|____| |____|____|____| |
| | | |+ |
|4 |5 |6 | |
|(L) | |(R) | |
| 6B| 73| 74| 79|
____ |____|____|____|____|
| | | | | | |
|(U) | |1 |2 |3 | |
|[1] | |End |(D) |PgDn| |
|E075| | 69| 72| 7A|Ent |
____|____|____ |____|____|____| |
| | | | | | | |
|(L) |(D) |(R) | |0 |. | |
|[1] |[1] |[1] | |Ins |Del | |
|E06B|E072|E074| | 70| 71|E05A|
|____|____|____| |_________|____|____|
code key code key code key code key
---- --- ---- --- ---- --- ---- ---
01 F9 66 BackSpace
21 C 41 ,<
03 F5 22 X 42 K 69 End 1
04 F3 23 D 43 I
05 F1 24 E 44 O 6B (left) 4
06 F2 25 4$ 45 0) 6C Home 7
07 F12 26 3# 46 9(
70 Ins 0
09 F10 29 Space 49 .> 71 Del .
0A F8 2A V 4A /? 72 (down) 2
0B F6 2B F 4B L 73 5
0C F4 2C T 4C ;: 74 (right) 6
0D Tab 2D R 4D P 75 (up) 8
0E `~ 2E 5% 4E -_ 76 Esc
77 NumLock
11 L Alt 31 N 52 '" 78 F11
12 L Shift 32 B 79 +
33 H 54 [{ 7A PageDown 3
14 L Ctrl 34 G 55 =+ 7B -
15 Q 35 Y 7C *
16 1! 36 6^ 58 CapsLock 7D PageUp 9
59 R Shift 7E ScrollLock
1A Z 3A M 5A Enter
1B S 3B J 5B ]} 83 F7
1C A 3C U
1D W 3D 7& 5D \|
1E 2@ 3E 8*
code key
---- ---
E011 R Alt
E012E07C PrintScreen make code
E014 R Ctrl
E01F L Win
E027 R Win
E02F Menu
E04A /
E05A Enter (on numeric keypad)
E069 End
E06B Left
E06C Home
E070 Ins
E071 Del
E072 (down)
E074 (right)
E075 (up)
E07A PageDown
E07C PrintScreen repeat code
E07D PageUp
E0F07CE0F012 PrintScreen break code
E11477E1F014F077 Pause
====================================================================
SCANCODES FOR SCANCODE SET 3
====================================================================
US 104-key keyboard, set 3 scancodes
"Make" code is generated when key is pressed.
"Break" code is generated when key is released.
Hex value of make code for each key is shown.
All keys:
one-byte make code = nn
one-byte repeat code = nn
two-byte break code = F0nn
When operating in scancode set 3, the keyboard
does not maintain an internal NumLock state.
____ ___________________ ___________________ ___________________
| | | | | | | | | | | | | | | | |
|Esc | |F1 |F2 |F3 |F4 | |F5 |F6 |F7 |F8 | |F9 |F10 |F11 |F12 |
| | | | | | | | | | | | | | | | |
| 08| | 07| 0F| 17| 1F| | 27| 2F| 37| 3F| | 47| 4F| 56| 5E|
|____| |____|____|____|____| |____|____|____|____| |____|____|____|____|
__________________________________________________________________________
| | | | | | | | | | | | | | | |
|~ |! |@ |# |$ |% |^ |& |* |( |) |_ |+ || |bksp|
|` |1 |2 |3 |4 |5 |6 |7 |8 |9 |0 |- |= |\ | |
| 0E| 16| 1E| 26| 25| 2E| 36| 3D| 3E| 46| 45| 4E| 55| 5C| 66|
|____|____|____|____|____|____|____|____|____|____|____|____|____|____|____|
| | | | | | | | | | | | | | |
|Tab |Q |W |E |R |T |Y |U |I |O |P |{ |} | |
| | | | | | | | | | | |[ |] | |
| 0D| 15| 1D| 24| 2D| 2C| 35| 3C| 43| 44| 4D| 54| 5B| |
|____|____|____|____|____|____|____|____|____|____|____|____|____| |
| | | | | | | | | | | | | |
|Caps|A |S |D |F |G |H |J |K |L |: |" | Enter |
| | | | | | | | | | |; |' | |
| 14| 1C| 1B| 23| 2B| 34| 33| 3B| 42| 4B| 4C| 52| 5A|
|____|____|____|____|____|____|____|____|____|____|____|____|______________|
| | | | | | | | | | | | |
| L Shift |Z |X |C |V |B |N |M |< |> |? | R Shift |
| | | | | | | | |, |. |/ | |
| 12| 1A| 22| 21| 2A| 32| 31| 3A| 41| 49| 4A| 59|
|_________|____|____|____|____|____|____|____|____|____|____|______________|
| | | | | | | | |
|L Ctrl | L win | L Alt | space | R Alt | R win | menu |R Ctrl |
| | | | | | | | |
| 11| 8B| 19| 29| 39| 8C| 8D| 58|
|_______|_______|_______|__________________|_______|_______|_______|_______|
____ ____ ____
| | | |
|Prt |Scrl|Paus|
|Scrn|Lock|Brk |
| 57| 5F| 62|
|____|____|____|
____ ____ ____ ____ ____ ____ ____
| | | | | | | | |
|Ins |Home|PgUp| |Num |/ |* |- |
| | | | |Lock| | | |
| 67| 6E| 6F| | 76| 77| 7E| 84|
|____|____|____| |____|____|____|____|
| | | | | | | | |
|Del |End |PgDn| |7 |8 |9 | |
| | | | |Home|(U) |PgUp| |
| 64| 65| 6D| | 6C| 75| 7D| |
|____|____|____| |____|____|____| |
| | | |+ |
|4 |5 |6 | |
|(L) | |(R) | |
| 6B| 73| 74| 7C|
____ |____|____|____|____|
| | | | | | |
|(U) | |1 |2 |3 | |
| | |End |(D) |PgDn| |
| 63| | 69| 72| 7A|Ent |
____|____|____ |____|____|____| |
| | | | | | | |
|(L) |(D) |(R) | |0 |. | |
| | | | |Ins |Del | |
| 61| 60| 6A| | 70| 71| 79|
|____|____|____| |_________|____|____|
code key code key code key code key
---- --- ---- --- ---- --- ---- ---
07 F1 2A V 4A /? 6B (left) 4
08 Esc 2B F 4B L 6C Home 7
2C T 4C ;: 6D PageDown
0D Tab 2D R 4D P 6E Home
0E `~ 2E 5% 4E -_ 6F PageUp
0F F2 2F F6 4F F10 70 Ins 0
71 Del .
11 L Ctrl 31 N 52 '" 72 (down) 2
12 L Shift 32 B 73 5
33 H 54 [{ 74 (right) 6
14 CapsLock 34 G 55 =+ 75 (up) 8
15 Q 35 Y 56 F11 76 NumLock
16 1! 36 6^ 57 PrintScr 77 /
17 F3 37 F7 58 R Ctrl
59 R Shift 79 Enter (on numeric keypad)
19 L Alt 39 R Alt 5A Enter 7A PageDown 3
1A Z 3A M 5B ]}
1B S 3B J 5C \| 7C +
1C A 3C U 7D PageUp 9
1D W 3D 7& 5E F12 7E *
1E 2@ 3E 8* 5F ScrollLock
1F F4 3F F8 60 (down) 84 -
61 (left)
21 C 41 ,< 62 Pause 8B L Win
22 X 42 K 63 (up) 8C R Win
23 D 43 I 64 Del 8D Menu
24 E 44 O 65 End
25 4$ 45 0) 66 BackSpace
26 3# 46 9( 67 Ins
27 F5 47 F9
69 End 1
29 Space 49 .> 6A (right)
