HP dx7300 Technical Reference Manual page 94

Input/Output Interfaces
Table 5-13 lists and describes commands that can be issued by the 8042 to the keyboard.
Command
Set/Reset Status Indicators
Echo
Invalid Command
Select Alternate Scan Codes
Read ID
Set Typematic Rate/Display
Enable
Default Disable
Set Default
Set Keys—Typematic
5-16
Table 5-13.
8042-To-Keyboard Commands
Value Description
EDh Enables LED indicators. Value EDh is followed by an option
byte that specifies the indicator as follows:
Bits <7..3> not used
Bit <2>, Caps Lock (0 = off, 1 = on)
Bit <1>, NUM Lock (0 = off, 1 = on)
Bit <0>, Scroll Lock (0 = off, 1 = on)
EEh Keyboard returns EEh when previously enabled.
EFh/F1h These commands are not acknowledged.
F0h Instructs the keyboard to select another set of scan codes
and sends an option byte after ACK is received:
01h = Mode 1
02h = Mode 2
03h = Mode 3
F2h Instructs the keyboard to stop scanning and return two
keyboard ID bytes.
F3h Instructs the keyboard to change typematic rate and delay to
specified values:
Bit <7>, Reserved—0
Bits <6,5>, Delay Time
Bits <4..0>, Transmission Rate:
F4h Instructs keyboard to clear output buffer and last typematic
key and begin key scanning.
F5h Resets keyboard to power-on default state and halts scanning
pending next 8042 command.
F6h Resets keyboard to power-on default state and enable
scanning.
F7h Clears keyboard buffer and sets default scan code set. [1]
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00 = 250 ms
01 = 500 ms
10 = 750 ms
1 1 = 1000 ms
00000 = 30.0 ms
00001 = 26.6 ms
00010 = 24.0 ms
0001 1 = 21.8 ms
:
1 1 1 1 1 = 2.0 ms
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