Compaq dc7100 HP Compaq dc71xx and dx61xx Series Business Desktop Computers Te - Page 105
Table 5-16., To-Keyboard Commands
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Input/Output Interfaces Table 5-16 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 Table 5-16. 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 not used Bit , Caps Lock (0 = off, 1 = on) Bit , NUM Lock (0 = off, 1 = on) Bit , 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 , Reserved-0 Bits , Delay Time 00 = 250 ms 01 = 500 ms 10 = 750 ms 11 = 1000 ms Bits , Transmission Rate: 00000 = 30.0 ms 00001 = 26.6 ms 00010 = 24.0 ms 00011 = 21.8 ms : 11111 = 2.0 ms 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] Technical Reference Guide 361834-002 5-19