w83l950d Winbond Electronics Corp America, w83l950d Datasheet - Page 48

• Manufacturer Part Number: w83l950d
• Description: Peripheral Personal Computer Keyboard Controller
• Manufacturer: Winbond Electronics Corp America

10.13.1 KB Control Register (KBCTRL)
10.13.2 Port 92 Control Register
Bit 2: P92EN (Port 92 Enable)
The Port92 function is effective when the chip is in LPC mode.
A "1" on this bit enables Port 92 to control GATEA20 and KBRESET.
A "0" on this bit disables Port 92 functions.
Bit 1: 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.
Bit 0: HKBRST (Hardware Keyboard Reset)
A "1" on this bit selects hardware KB RESET control logic to control KBRESET signal.
A "0" on this bit disables 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 6µS(Min.) with 14µS(Min.) delay.
GATEA20 and KBRESET are controlled by either the software control or the hardware control
logic and they are mutually exclusive. Then, GATEA20 and KBRESET are merged along with
Port92 control logic when P92EN bit is set.
Host address
Default Value
SGA20 (Special GATE A20 Control)
A "1" on this bit drives GATE A20 signal to high.
A "0" on this bit drives GATE A20 signal to low.
PLKBRST (Pull-Low KBRESET)
A "1" on this bit causes KBRESET to drive low for 6µS(Min.) with 14µS(Min.) delay. Before
issuing another keyboard reset command, the bit must be cleared.
Bit
Name
NAME
BIT
The register KBCTRL is effective when the BUS interface is enable.
Res. (0) Res. (0) Res. (1) Res. (0) Res. (0) Res. (1)
7
7
0x92
0x00
6
6
Reserved
5
5
4
4
- 39 -
3
3
Publication Release Date: June 23, 2003
2
P92EN
2
SGA20
1
HGA20
W83L950D
1
Revision 1.0
PLKBRST
HKBRST
0
0