Datasheet

Signal Description
R
48 Datasheet
2.6.6 Graphics General Purpose Input/Output Signals
Table 18. Graphics GPIO Signal Descriptions
GPIO I/F Total Type Comments
AGPBUSY# O
CMOS
AGPBUSY: Output of the GMCH IGD to the ICH4-M, which indicates that
certain graphics activity is taking place. It will indicate to the ACPI
software not to enter the C3 state. It will also cause a C3/C4 exit if C3/C4
was being entered, or was already entered when AGPBUSY# went
active. Not active when the IGD is in any ACPI state other than D0.
EXTTS_0 I
CMOS
External Thermal Sensor Input: This signal is an active low input to the
GMCH/MCH and is used to monitor the thermal condition around the
system memory and is used for triggering a read throttle. The
GMCH/MCH can be optionally programmed to send a SERR, SCI, or SMI
message to the ICH4-M upon the triggering of this signal.
Panel Power Sequencing Control Signals
PANELVDDEN O
CMOS
LVDS LCD Flat Panel Power Control: This signal is used to enable the
power to the panel interface.
PANELBKLTEN O
CMOS
LVDS LCD Flat Panel Backlight Enable: This signal is used to enable
the backlight inverter (BLI).
PANELBKLTCTL O
CMOS
LVDS LCD Flat Panel Backlight Brightness Control: This signal is
used as the Pulse Width Modulated (PWM) control signal to inverter for
control the of backlight brightness.
GPIO pins for DDC/GMBUS support
LCLKCTLA O
CMOS
SSC Chip Clock Control: Can be used to control an external clock chip
with SSC control. If external SSC chip not used, may optionally use for
DDC/GMBUS support.
LCLKCTLB O
CMOS
SSC Chip Data Control: Can be used to control an external clock chip
for SSC control. If external SSC chip not used, may optionally use for
DDC/GMBUS support.
DDCACLK I/O
CMOS
CRT DDC Clock: This signal is used as the DDC clock signal between
the CRT monitor and the GMCH.
DDCADATA I/O
CMOS
CRT DDC Data: This signal is used as the DDC data signal between the
CRT monitor and the GMCH.
DDCPCLK I/O
CMOS
Panel DDC Clock: This signal is used as the DDC clock signal between
the LFP and the GMCH.
DDCPDATA I/O
CMOS
Panel DDC Data: This signal is used as the DDC data signal between
the LFP and the GMCH.
GPIO pins for DDC/GMBUS support
MI2CCLK I/O
DVO
DVO I2C Clock: This signal is used as the I2C_CLK for a digital display
(i.e. TV-Out Encoder, TMDS transmitter). This signal is tri-stated during a
hard reset.