w83977atg Winbond Electronics Corp America, w83977atg Datasheet - Page 109

• Manufacturer Part Number: w83977atg
• Description: W83877tf Plus Kbc, Gp I/o, Wake-up, Fir, Cir, Pb-free
• Manufacturer: Winbond Electronics Corp America

Commands, continued
9.5
The KBC implements a hardware control logic to speed-up GATEA20 and KBRESET. This control
logic is controlled by LD5-CRF0 as follows:
9.5.1
KCLKS1, KCLKS0
This 2 bits are for the KBC clock rate selection.
P92EN (Port 92 Enable)
A "1" on this bit enables Port 92 to control GATEA20 and KBRESET.
A "0" on this bit disables Port 92 functions.
HGA20 (Hardware GATE A20)
A "1" on this bit selects hardware GATEA20 control logic to control GATE A20 signal.
A "0" on this bit disables hardware GATEA20 control logic function.
HKBRST (Hardware Keyboard Reset)
A "1" on this bit selects hardware KB RESET control logic to control KBRESET signal.
A "0" on this bit disable hardware KB RESET control logic function.
When the KBC receives data that follows a "D1" command, the hardware control logic sets or clears
GATE A20 according to the received data bit 1. Similarly, the hardware control logic sets or clears
KBRESET depending on the received data bit 0. When the KBC receives a "FE" command, the
KBRESET is pulse low for 6 μ S (Min.) with 14 μ S (Min.) delay.
NAME
BIT
HARDWARE GATEA20/KEYBOARD RESET CONTROL LOGIC
COMMAND
KB Control Register (Logic Device 5, CR-F0)
= 0 0
= 0 1
= 1 0
= 1 1
D2h
D3h
D4h
E0h
FXh
KCLKS1
7
KCLKS0
KBC clock input is 6 Mhz
KBC clock input is 8 Mhz
KBC clock input is 12 Mhz
KBC clock input is 16 Mhz
Send data back to the system as if it came from Keyboard
Send data back to the system as if it came from Auxiliary Device
Output next received byte of data from system to Auxiliary Device
Reports the status of the test inputs
Pulse only RC(the reset line) low for 6 μ S if Command byte is even
6
Reserved
5
Reserved
- 101 -
4
W83977ATF/W83977ATG
Reserved
FUNCTION
3
Publication Release Date: May 2006
P92EN
2
HGA20
1
Revision 0.6
HKBRST
0