HP dc71xx Manuale Utente
C-10
361834-002
Technical Reference Guide
Keyboard
C.2.5 Keyboard Commands
Table C-1 lists the commands that the keyboard can send to the system (specifically, to the
8042-type logic).
8042-type logic).
Note:
[1] Modes 2 and 3.
[2] Mode 1 only.
[2] Mode 1 only.
Table C-1.
Keyboard-to-System Commands
Command
Value
Description
Key Detection Error/Over/run
00h [1]
FFh [2]
FFh [2]
Indicates to the system that a switch closure
couldn’t be identified.
couldn’t be identified.
BAT Completion
AAh
Indicates to the system that the BAT has been
successful.
successful.
BAT Failure
FCh
Indicates failure of the BAT by the keyboard.
Echo
EEh
Indicates that the Echo command was received by
the keyboard.
the keyboard.
Acknowledge (ACK)
FAh
Issued by the keyboard as a response to valid
system inputs (except the Echo and Resend
commands).
system inputs (except the Echo and Resend
commands).
Resend
FEh
Issued by the keyboard following an invalid input.
Keyboard ID
83ABh
Upon receipt of the Read ID command from the
system, the keyboard issues the ACK command
followed by the two IDS bytes.
system, the keyboard issues the ACK command
followed by the two IDS bytes.