MEC1404 Datasheet, PDF (271/572 Pages) Microchip Technology – Keyboard and Embedded Controller Products for Notebook PC

MEC140X/1X
16.18 Emulated 8042 Interface EC-Only Registers
The registers listed in the EC-Only Register Summary table are for a single instance of the Legacy Port92/GATEA20
logic. The addresses of each register listed in this table are defined as a relative offset to the host “Base Address”
defined in the EC-Only Register Base Address Table.
TABLE 16-15: EC-ONLY REGISTER BASE ADDRESS TABLE
Block Instance
Port92-Legacy
Instance Number
0
Host
EC
Address Space
32-bit address
space
Base Address
000F_1900h
The Base Address indicates where the first register can be accessed in a particular address space for a block instance.
TABLE 16-16: EC-ONLY REGISTER SUMMARY
Offset
0h
8h
Ch
Register Name (Mnemonic)
GATEA20 Control Register
SETGA20L Register
RSTGA20L Register
16.18.1 GATEA20 CONTROL REGISTER
Offset ^0h
Bits
Description
7:1 Reserved
0 GATEA20
0=The GATEA20 output is driven low
1=The GATEA20 output is driven high
16.18.2 SETGA20L REGISTER
Type
R
R/W
Default
-
0h
Reset
Event
-
nSYSR
ST
Offset ^08h
Bits
Description
7:0 SETGA20L
See Section 16.11.1, "GATE A20 Speedup" for information on this
register. A write to this register sets GATEA20 in the GATEA20
Control Register.
Type
W
Default
-
Reset
Event
-
 2015 - 2016 Microchip Technology Inc.
DS00001956D-page 271