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).
Note:
[1] Modes 2 and 3.
[2] Mode 1 only.
Table C-1.
Keyboard-to-System Commands
Command
Value
Description
Key Detection Error/Over/run
00h [1]
FFh [2]
Indicates to the system that a switch closure
couldn’t be identified.
BAT Completion
AAh
Indicates to the system that the BAT has been
successful.
BAT Failure
FCh
Indicates failure of the BAT by the keyboard.
Echo
EEh
Indicates that the Echo command was received by
the keyboard.
Acknowledge (ACK)
FAh
Issued by the keyboard as a response to valid
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.
Summary of Contents for Compaq dc71 Series
Page 50: ...2 34 361834 002 Technical Reference Guide System Overview ...
Page 58: ...3 8 361834 002 Technical Reference Guide Processor Memory Subsystem ...
Page 126: ...5 40 361834 002 Technical Reference Guide Input Output Interfaces ...
Page 168: ...8 20 361834 002 Technical Reference Guide BIOS ROM ...
Page 188: ...A 20 361834 002 Technical Reference Guide Error Messages and Codes ...
Page 192: ...B 4 361834 002 Technical Reference Guide ASCII Character Set ...
Page 210: ...C 18 361834 002 Technical Reference Guide Keyboard ...