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5.1 Intel 915PM North Bridge(4)

DDR / DDR2 SDRAM Channel B Interface

Signal Name Type Description
SB_DQ[63:0] I/O
SSTL1.8/2
2x
Data Lines:
DDR / DDR2 Channel B data signal interface to the SDRAM data
bus.
Single Channel mode: No connect.
Dual channel mode: Route to SO-DIMM B
NOTE: Signals do not exist in Intel 915GMS.
SB_DM[7:0] O
SSTL1.8/2
2x
Data Mask:
When activated during writes, the corresponding data groups in the
SDRAM are masked. There is one SB_DM[7:0] fo r every data byte
lane. These signals are used to mask individual bytes of data in the
case of a partial write, and to interrupt burst writes.
Single Channel mode: No connect.
Dual channel mode: Route to SO-DIMM B
NOTE: Signals do not exist in Intel 915GMS.
SB_DQS[7:0] I/O
SSTL1.8/2
2x
Data Strobes:
DDR: The rising and falling edges of SB_DQS[7:0] are used for
capturing data during read and write transactions.
DDR2: SB_DQS[7:0] and its complement signal group make up a
differential strobe pair. The data is captured at the crossing point of
SB_DQS[7:0] and its SB_DQS[7:0]# during read and write
transactions.
Single Channel mode: No connect.
Dual channel mode: Route to SO-DIMM B
NOTE: Signals do not exist in Intel 915GMS.
SB_DQS[7:0]# I/O
SSTL1.8
2x
Data Strobe Complements (DDR2 only):
DDR1: No Connect. These s ignals are not used for DDR devices
DDR2 : These are the complementary DDR2 strobe signals.
Single Channel mode: No connect.
Dual channel mode: Route to SO-DIMM B
NOTE: Signals do not exist in Intel 915GMS.
SB_MA[13:0] O
SSTL1.8/2 Memory Address:
These signals are used to provide the multiplexed row and column
address to the SDRAM.
Single channel mode: Route to SO-DIMM 1
Dual channel mode: Route to SO-DIMM B
NOTE: SB_MA13 is for support of 1 Gb devices.
SB_BS[2:0] O
SSTL1.8/2 Bank Select:
These signals define which banks are selected within each
SDRAM rank.
Single channel mode: Route to SO-DIMM 1
Dual channel mode: Route to SO-DIMM B
NOTE: SB_BS2 is for DDR2 support only.

DDR / DDR2 SDRAM Channel B Interface (Continued)

Signal Name Type Description
SB_RAS# O
SSTL1.8/2 RAS Control signal:
Used with SB_CAS# and SB_WE# (along with SM_CS#) to define
the SDRAM commands.
Single channel mode: Route to SO-DIMM 1
Dual channel mode: Route to SO-DIMM B
SB_CAS# O
SSTL1.8/2 CAS Control signal:
Used with SB_RAS# and SB_WE# (along with SM_CS#) to define
the SDRAM commands.
Single channel mode: Route to SO-DIMM 1
Dual channel mode: Route to SO-DIMM B
SB_WE# O
SSTL1.8/2 Write Enable Control signal:
Used with SB_RAS# and SB_CAS# (along with SM_CS#) to define
the SDRAM commands.
Single channel mode: Route to SO-DIMM 1
Dual channel mode: Route to SO-DIMM B
SB_RCVENIN# I
SSTL1.8/2 Clock Input:
Used to emulate source-synch clocking for reads.
Leave as No Connect.
NOTE: Signals do not exist in Intel 915GMS.
SB_RCVENOUT
# O
SSTL1.8/2 Clock Output:
Used to emulate source-synch clocking for reads.
Leave as No Connect.
NOTE: Signals do not exist in Intel 915GMS.

DMI

Signal Name Type Description
DMI_RXP[3:0]
DMI_RXN[3:0]
I
PCIE DMI input from ICH6-M:
Direct Media Interface rec eive differential p air
DMI_TXP[3:0]
DMI_TXN[3:0]
O
PCIE DMI output to ICH6-M:
Direct Media Interface transmit differential pair
DMI x2 or x4 is supported for Intel 915GM, Intel 915PM and Intel 910GML chipsets.
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