Controller Commands - HP Vectra Technical Reference Manual

Table 5.17
Controller Commands
Command Type Description
020H
READ Reads byte zero of the 8041's internal RAM. This byte is the last
Keyboard Command Sent to the 8041.
021H-03FH
READ
Reads the byte specified by the lower five bits of the command
in the 8041's internal RAM. E.g. 8041 Controller command 34H
will report contents of the 14H byte of the 8041's RAM.
060H-07FH
DBL Writes the data byte to the address specified in the low five bits
of the command.
OAAH
SNGL Initiate Self-Test. This command instructs the 8041 to perform a
self test. If no errors are detected, 55H is returned in the Data
Port.
OASH
SNGL Initiate Interface Test. This command instructs the 8041 to test
the interface between itself and the keyboard. (Always returns 0
=
successful)
OACH
READ Diagnostic Dump. The contents of the 8041 internal RAM
registers (16 bytes), output port, input port, and status word are
sent to the system. All diagnostic data is sent to the system in
the same manner as scancodes. (Not supported)
OADH
SNGL Disable Keyboard. This command disables the keyboard. Bit 4 of
the current command byte will be set to '1' in the 8041 . This is
equivalent to issuing a command byte with bit 4 set to '1'. Note
that this command will have no effect if bit 3 of the command
byte is set to '1'.
OAEH
SNGL Enable Keyboard. This command re-enables the keyboard. Bit
4 of the current command byte is cleared in the 8041. This is
equivalent to issuing a command byte with bit 4 set to '0'.
OCOH
READ
Read Input Port. The current value of the input port is returned.
Bit 7 indicates the status of the front panel keylock. Bits 0-3
will always be reported as '1'. Bits 4-6 are undefined.
OOOH
READ
Read Output Port. The current value of the output port is
returned. See table 5.20 for bit definitions.
184 Keyboard