122
8175 N/B MAINTENANCE
8175 N/B MAINTENANCE
5.2 Intel 82845(Brookdale Memory Controller HUB)
AGP/PCISignals
Name
Type
Description
G_PAR
I/O
AGP
Parity:
During FRAME# Operations:
This signal is driven by the MCH
when it acts as a FRAME#-based AGP initiator during address and
data phases for a write cycle, and during the address phase for a read
cycle. PAR is driven by the MCH when it acts as a FRAME#-based
AGP target during each data phase of a FRAME#-based AGP
memory read cycle. Even parity is generated across AD[31:0] and
G_C/BE[3:0]#.
During SBA and PIPE# Operation:
This signal is not used during
SBA and PIPE# operation.
Clocks, Reset, and Miscellaneous Signals
Name
Type
Description
BCLK
BCLK#
I
CMOS
Differential Host Clock In:
These pins receive a differential host
clock from the external clock synthesizer. This clock is used by all of
the MCH logic that is in the host clock domain.
66IN
I
CMOS
66 MHz Clock In:
This pin receives a 66 MHz clock from the clock
synthesizer. This clock is used by AGP/PCI and hub interface clock
domains.
Note:
That this clock input is 3.3 V tolerant.
SCK[11:0]
O
CMOS
System Memory Clocks (SDR):
These signals deliver a
synchronized clock to the DIMMs. There are two per row.
RSTIN#
I
CMOS
Reset In:
When asserted, this signal asynchronously resets the MCH
logic. RSTIN# is connected to the PCIRST# output of the ICH2. All
AGP/PCI output and bi-directional signals will also three-state
compliant to PCI Rev 2.0 and 2.1 specifications.
Note:
This input needs to be 3.3 V tolerant.
TESTIN#
I
CMOS
Test Input:
This pin is used for manufacturing and board level test
purposes.
Note:
This signal has an internal pull-up resistor.
Voltage Reference and Power Signals
Name
Type
Description
HVREF
Ref
Host Reference Voltage:
Reference voltage input for the data,
address, and common clock signals of the host AGTL+ interface.
SDREF
Ref
SDRAM Reference Voltage:
Reference voltage input for DQ, DQS,
RDCLKIN (SDR).
HI_REF
Ref
Hub Interface Reference:
Reference voltage input for the hub
interface.
AGPREF
Ref
AGP Reference:
Reference voltage input for the AGP interface.
HLRCOMP
I/O
CMOS
Compensation for Hub Interface:
This signal is used to calibrate
the hub interface I/O buffers. It is connected to a 40.2 . pull-up
resistor with 1% tolerance and is pulled up to VCC1_8.
GRCOMP
I/O
CMOS
Compensation for AGP:
This signal is used to calibrate buffers. It is
connected to a 40.2 . pull-down resistor with a 1% tolerance.
HRCOMP[1:0]
I/O
CMOS
Compensation for Host:
These signals are used to calibrate the host
AGTL+ I/O buffers. Each signal is connected to a 24.9 . pull-down
resistor with a 1% tolerance.
HSWNG[1:0]
I
CMOS
Host Reference Voltage:
Reference voltage input for the
compensation logic.
SMRCOMP
I/O
CMOS
System Memory RCOMP:
VCC1_5
1.5 V Power Input:
These pins are connected to a 1.5 V power
source.
VCC1_8
1.8 V Power Input Pins:
These pins are connected to a 1.8 V power
source.
VCCSM
SDRAM Power Input Pins:
These pins are connected to a 3.3 V
power source for SDR.
VCCA[1:0]
PLL Power Input Pins:
These pins provide power for the PLL.
VTT
AGTL+ Bus Termination Voltage Inputs:
These pins provide the
AGTL+ bus termination.
VSS
Ground:
The VSS pins are the ground pins for the MCH.
VSSA[1:0]
PLL Ground:
The VSSA[1:0] pins are the ground pins for the PLL
on the MCH.
