W83977EF Winbond Electronics Corp America, W83977EF Datasheet - Page 79

• Manufacturer Part Number: W83977EF
• Description: Description = W83877TF Plus Kbc, GP I/O, Wake-Up, Power Fail Resume ;; Package = QFP 128
• Manufacturer: Winbond Electronics Corp America

6.4
6.5 Hardware GATEA20/Keyboard Reset Control Logic
The KBC implements a hardware control logic to speed-up GATEA20 and KBRESET. This control
logic is controlled by LD5-CRF0 as follows:
COMMAND
Commands,CONTINUED
ABh
ADh
AEh
C0h
C1h
C2h
D0h
D1h
D2h
D3h
D4h
E0h
FXh
Interface Test
Disable Keyboard Interface
Enable Keyboard Interface
Read Input Port(P1) and send data to the system
Continuously puts the lower four bits of Port1 into STATUS register
Continuously puts the upper four bits of Port1 into STATUS register
Send Port2 value to the system
Only set/reset GateA20 line based on the system data bit 1
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
BIT
00
01
02
03
04
No Error Detected
Keyboard "Clock" line is stuck high
Keyboard "Clock" line is stuck low
Keyboard "Data" line is stuck low
Keyboard "Data" line is stuck high
BIT DEFINITION
-73 -
FUNCTION
Publication Release Date: April 2003
W83977EF
Revision 1.1