
SiS5595 PCI System I/O Chipset
Preliminary V2.0 Nov. 2, 1998 56 Silicon Integrated Systems Corporation
AB
( Not Implemented in 5595)
Reference: Keyboard Interface Test – This command tests the keyboard
clock and data line, and the test result is placed in the output buffer as
follows :
00 – No Error detected.
01 – The ‘Keyboard Clock’ line is stuck low.
02 – The ‘Keyboard Clock’ line is stuck high.
03 – The ‘Keyboard Data’ line is stuck low.
04 – The ‘Keyboard Data’ line is stuck high.
Disable Keyboard Interface – This command would set the bit 4 of the
controller’s command byte, and disable the keyboard interface by driving the
clock line low. Data will not be sent or received.
Enable Keyboard Interface – This command would clear the bit 4 of
command byte and release the keyboard interface.
Read Internal Register D – The Internal Register will be placed into its
output buffer.
Write Internal Register D – The next byte of data written to I/O 60h is placed
in the controller’s Register D.
Read Internal Output Port – The value of P20 and P21 would be placed in
the bit 0 and bit 1 of the output buffer respectively. This command should be
issued only if the output buffer is empty.
Write Internal Output Port – The bit 0 and bit 1 of the next byte written to I/O
60h would be placed in the P20 and P21 respectively. The other bits are
reserved and should be written to ‘1’.
Write Keyboard Output Buffer – The next byte of data written to I/O port 60h
is placed in output buffer as it received from keyboard.
Not Valid
AD
AE
CA
CB
D0
D1
D2
D3
Write Mouse Output Buffer – The next
byte of data written to I/O port 60h is
placed in output buffer as it received
from mouse.
Write Mouse Device – The next byte
written to I/O 60h is transmitted to
mouse device.
D4
Not Valid
D6
Enable Keyboard Lock < KLOCK#> Switch (Default: Enable) – The KLOCK#
function will work if the KLOCK# function enable bit is enabled.
Disable Keyboard Lock Switch < KLOCK# > – The KLOCK# function won’t
work even when the KLOCK# function enable bit is enabled.
D7
3.8.5 PASSWORD SECURITY AND KEYBOARD POWER UP FUNCTIONS
Traditional password security function in the KBC has provided the ability of protecting your
PC from being invaded. SiS5595/KBC supports the function with registers to store the
password character string, and a pattern recognition circuitry to identify if an input character
string matches the pre-loaded password.