W83977EF Datasheet, PDF (79/150 Pages) Winbond – WINBOND I/O

W83977EF
6.4
Commands,CONTINUED
COMMAND
ABh
Interface Test
FUNCTION
BIT
BIT DEFINITION
00
No Error Detected
01
Keyboard "Clock" line is stuck low
02
Keyboard "Clock" line is stuck high
03
Keyboard "Data" line is stuck low
04
Keyboard "Data" line is stuck high
ADh
Disable Keyboard Interface
AEh
Enable Keyboard Interface
C0h
Read Input Port(P1) and send data to the system
C1h
Continuously puts the lower four bits of Port1 into STATUS register
C2h
Continuously puts the upper four bits of Port1 into STATUS register
D0h
Send Port2 value to the system
D1h
Only set/reset GateA20 line based on the system data bit 1
D2h
Send data back to the system as if it came from Keyboard
D3h
Send data back to the system as if it came from Auxiliary Device
D4h
Output next received byte of data from system to Auxiliary Device
E0h
Reports the status of the test inputs
FXh
Pulse only RC(the reset line) low for 6µS if Command byte is even
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:
Publication Release Date: April 2003
-73 -
Revision 1.1