Intel® 854 Graphics Memory Controller Hub (GMCH)

3.5.4General Purpose Input/Output Signals

Table 13. GPIO Signal Descriptions

GPIO I/F Total

Type

Comments

 

 

 

RSTIN#

I

Reset: Primary Reset, Connected to PCIRST# of ICH4-M.

 

CMOS

 

 

 

 

PWROK

I

Power OK: Indicates that power to GMCH is stable.

 

CMOS

 

 

 

 

EXTTS_0

I

External Thermal Sensor Input: This signal is an active low input to the

 

CMOS

GMCH and is used to monitor the thermal condition around the system memory

 

and is used for triggering a read throttle. The GMCH can be optionally

 

 

 

 

programmed to send a SERR, SCI, or SMI message to the ICH4-M upon the

 

 

triggering of this signal.

 

 

 

LCLKCTLA

O

SSC Chip Clock Control: Can be used to control an external clock chip with

 

CMOS

SSC control.

 

 

 

 

 

LCLKCTLB

O

SSC Chip Data Control: Can be used to control an external clock chip for

 

 

SSC control.

 

CMOS

 

 

 

 

DDCACLK

I/O

CRT DDC Clock: This signal is used as the DDC clock signal between the

 

 

CRT monitor and the GMCH.

 

CMOS

 

 

 

 

DDCADATA

I/O

CRT DDC Data: This signal is used as the DDC data signal between the CRT

 

 

monitor and the GMCH.

 

CMOS

 

 

 

 

MI2CCLK

I/O

DVO I2C Clock: This signal is used as the I2C_CLK for a digital display (i.e.

 

DVO

TV-Out Encoder, TMDS transmitter). This signal is tri-stated during a hard

 

reset.

 

 

 

 

 

MI2CDATA

I/O

DVO I2C Data: This signal is used as the I2C_DATA for a digital display (i.e.

 

DVO

TV-Out Encoder, TMDS transmitter). This signal is tri-stated during a hard

 

reset.

 

 

 

 

 

MDVICLK

I/O

DVI DDC Clock: This signal is used as the DDC clock for a digital display

 

DVO

connector (that is, primary digital monitor). This signal is tri-stated during a hard

 

reset.

 

 

 

 

 

MDVIDATA

I/O

DVI DDC Data: The signal is used as the DDC data for a digital display

 

DVO

connector (that is, the primary digital monitor). This signal is tri-stated during a

 

hard reset.

 

 

 

 

 

MDDCDATA

I/O

DVI DDC Clock: The signal is used as the DDC data for a digital display

 

DVO

connector (that is, the secondary digital monitor). This signal is tri-stated during

 

a hard reset.

 

 

 

 

 

MDDCCLK

I/O

DVI DDC Data: The signal is used as the DDC clock for a digital display

 

DVO

connector (that is, the secondary digital monitor). This signal is tri-stated during

 

a hard reset.

 

 

 

 

 

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D15343-003

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Intel D15343-003 manual General Purpose Input/Output Signals, Gpio Signal Descriptions