GXM datasheet(29/244 Pages) NSC

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Signal Definitions (Continued)

GNT[2:0]#

E1,

F2,

H2,

K4,

Grant Lines

Grant indicates to the requesting master that it has been granted

access to the bus. Each master has its own GNT# line. GNT#

can be pulled away at any time a higher REQ# is received or if

the master does not begin a cycle within a minimum period of

time (16 SYSCLKs).

2.2.2

PCI Interface Signals (Continued)

Signal Name

BGA

Pin No.

SPGA

Pin No

Type

Description

2.2.3

Memory Controller Interface Signals

Signal Name

BGA

Pin No.

SPGA

Pin No.

Type

Description

Note:

The memory controller interface supports two types of memory configurations: SDRAM modules on the sys-

tem board and JEDEC DIMM connectors. Refer to Section 4.3 “Memory Controller” on page 103 for detailed

information regarding signal connections.

MD[63:0]

Refer

to Table

2-3

Refer

to Table

2-5

I/O

Memory Data Bus

The data bus lines driven to/from system memory.

MA[12:0]

Refer

to Table

2-3

Refer

to Table

2-5

Memory Address Bus

The multiplexed row/column address lines driven to the system

memory.

Supports 256 Mbit SDRAM.

BA[1:0]

AD26,

AD25

AJ33,

AK36

Bank Address Bits

These bits are used to select the component bank within the

SDRAM.

CS[3:0]#

AE23,

V25,

AD23,

V26

AK32,

Z34,

AN33,

AA35

Chip Selects

The chip selects are used to select the module bank within the

system memory. Each chip select corresponds to a specific mod-

ule bank.

If CS# is high, the bank(s) do not respond to RAS#, CAS#, WE#

until the bank is selected again.

RASA#,

RASB#

W24,

W25

AB36,

AB34

Row Address Strobe

RAS#, CAS#, WE# and CKE are encoded to support the differ-

ent SDRAM commands. RASA# is used with CS[1:0]#. RASB#

is used with CS[3:2]#.

CASA#,

CASB#

P25,

R26

W37,

X36

Column Address Strobe

RAS#, CAS#, WE# and CKE are encoded to support the differ-

ent SDRAM commands. CASA# is used with CS[1:0]#. CASB#

is used with CS[3:2]#.

WEA#,

WEB#

R25,

R24

W33,

W35

Write Enable

RAS#, CAS#, WE# and CKE are encoded to support the differ-

ent SDRAM commands. WEA# is used with CS[1:0]#. WEB# is

used with CS[3:2]#.

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