GXM datasheet(30/244 Pages) NSC

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Revision 3.1

Signal Definitions (Continued)

DQM[7:0]

Refer

to Table

2-3

Refer

to Table

2-5

Data Mask Control Bits

During memory read cycles, these outputs control whether the

SDRAM output buffers are driven on the MD bus or not. All DQM

signals are asserted during read cycles.

During memory write cycles, these outputs control whether or

not MD data will be written into the SDRAM.

DQM[7:0] connect directly to the DQM7-0 pins of each connec-

tor.

CKEA,

CKEB

AF24,

AD16

AL33,

AN23

Clock Enable

For normal operation CKE is held high. CKE goes low during

Suspend.

SDCLK[3:0]

AE4,

AF5,

AE5,

AF4

AM8,

AK10,

AL7,

AK8

SDRAM Clocks

The SDRAM samples all the control, address, and data using

these clocks.

SDCLK_IN

AE8

AK12

SDRAM Clock Input

The GXm processor samples the memory read data on this

clock. Works in conjunction with the SDCLK_OUT signal.

SDCLK_OUT

AF8

AL13

SDRAM Clock Output

This output is routed back to SDCLK_IN. The board designer

should vary the length of the board trace to control skew

between SDCLK_IN and SDCLK.

2.2.3

Memory Controller Interface Signals (Continued)

Signal Name

BGA

Pin No.

SPGA

Pin No.

Type

Description

2.2.4

Video Interface Signals

Signal Name

BGA

Pin No

SPGA

Pin No

Type

Description

PCLK

AC1

AJ1

Pixel Port Clock

Pixel Port Clock represents the pixel dotclock or a 2x multiple of

the dotclock for some 16-bit-per-pixel modes. It determines the

data transfer rate from the GXm processor to the CS5530.

VID_CLK

Video Clock

Video Clock represents the video port clock to the CS5530. This

pin is only used if the Video Port is enabled.

DCLK

AB1

AD4

DOT Clock

The DCLK input is driven from the CS5530 and represents the

pixel dot clock. In some cases, such as when displaying 16 BPP

data with an eight-bit-graphics pixel port, this clock will actually

be a 2x multiple of the dotclock.

CRT_HSYNC

AD2

CRT Horizontal Sync

CRT Horizontal Sync establishes the line rate and horizontal

retrace interval for an attached CRT. The polarity is programma-

ble and depends on the display mode.

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