MEC1322 datasheet(160/456 Pages) MICROCHIP

160 / 456 page

MEC1322

DS00001719D-page 160

 2014 - 2015 Microchip Technology Inc.

11.17.1

PORT 92 REGISTER

11.18 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.

The Base Address indicates where the first register can be accessed in a particular address space for a block instance.

Offset

Bits

Description

Type

Default

Reset

Event

7:2 Reserved

1 ALT_GATE_A20

This bit provides an alternate means for system control of the

GATEA20 pin. ALT_A20 low drives GATEA20 low, if A20 from the

keyboard controller is also low. When Port 92 is enabled, writing a 1

to this bit forces ALT_A20 high. ALT_A20 high drives GATEA20 high

regardless of the state of A20 from the keyboard controller.

0=ALT_A20 is driven low

1=ALT_A20 is driven high

R/W

nSIO_R

ESET

0 ALT_CPU_RESET

This bit provides an alternate means to generate a CPU_RESET

pulse. The CPU_RESET output provides a means to reset the sys-

tem CPU to effect a mode switch from Protected Virtual Address

Mode to the Real Address Mode. This provides a faster means of

reset than is provided through the EC keyboard controller. Writing a

“1” to this bit will cause the ALT_RST# internal signal to pulse (active

low) for a minimum of 6

μs after a delay of 14μs. Before another

ALT_RST# pulse can be generated, this bit must be written back to

“0”.

R/W

nSIO_R

ESET

TABLE 11-19: EC-ONLY REGISTER BASE ADDRESS TABLE

Block Instance

Instance Number

Host

Address Space

Base Address

Port92-Legacy

32-bit address

space

400F_1900h

TABLE 11-20: EC-ONLY REGISTER SUMMARY

Offset

GATEA20 Control Register

SETGA20L Register

RSTGA20L Register

MEC1322 датащи(PDF) 160 Page - Microchip Technology

MEC1322 датащи(HTML) 160 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL