Signal Description
R
Intel
®
82845 MCH for SDR Datasheet 23
2.2 SDR SDRAM Interface Signals
Signal Name Type Description
SCS[11:0]# O
CMOS
Chip Select: These signals select the particular SDRAM components
during the active state.
Note: There are two SCS# signals per SDRAM row. These signals can
be toggled on every rising system memory clock edge.
SMA[12:0] O
CMOS
Multiplexed Memory Address: These signals are used to provide the
multiplexed row and column address to SDRAM.
SBS[1:0] O
CMOS
Memory Bank Select: SBS[1:0] define the banks that are selected within
each SDRAM row. The SMA and SBS signals combine to address every
possible location in a SDRAM device.
SRAS# O
CMOS
SDRAM Row Address Strobe: SRAS# is Used with SCAS# and SWE#
(along with SCS#) to define the DRAM commands.
SCAS# O
CMOS
SDRAM Column Address Strobe: SCAS# is used with SRAS# and
SWE# (along with SCS#) to define the SDRAM commands.
SWE# O
CMOS
Write Enable: SWE# is used with SCAS# and SRAS# (along with SCS#)
to define the SDRAM commands.
SDQ[63:0] I/O
CMOS
Data Lines: These signals are used to interface to the SDRAM data bus.
SCB[7:0] I/O
CMOS
Check Bit Data Lines: These signals are used to interface to the
SDRAM ECC signals.
SCKE[5:0] O
CMOS
Clock Enable: These pins are used to signal a self-refresh or
Powerdown command to a SDRAM array when entering system
suspend. SCKE is also used to dynamically powerdown inactive SDRAM
rows. There is one SCKE per SDRAM row. These signals can be toggled
on every rising SCLK edge.
RDCLKO O
CMOS
Clock Output: RDCLKO is used to emulate source-synch clocking for
reads. This signal connects to RDCLKIN.
RDCLKIN I
CMOS
Clock Input: RDCLKIN is used to emulate source-synch clocking for
reads. This signal connects to RDCLKO.
2.3 Hub Interface Signals
Signal Name Type Description
HI_[10:0] I/O
CMOS
Hub Interface Signals: Signals used for the hub interface.
HI_STB I/O
CMOS
Hub Interface Strobe: One of two differential strobe signals used to
transmit or receive packet data over the hub interface.
HI_STB# I/O
CMOS
Hub Interface Strobe Compliment: One of two differential strobe
signals used to transmit or receive packet data over the hub interface.
