Signal Definitions
Table 5-1.
Signal Definitions (Sheet 3 of 8)
Name
Type
Description
Notes
D[63:0]#
I/O
D[63:0]# (Data) are the data signals. These signals provide a 64-bit data path
between the processor FSB agents, and must connect the appropriate pins on all
such agents. The data driver asserts DRDY# to indicate a valid data transfer.
3
D[63:0]# are quad-pumped signals, and will thus be driven four times in a
common clock period. D[63:0]# are latched off the falling edge of both
DSTBP[3:0]# and DSTBN[3:0]#. Each group of 16 data signals
correspond to a pair of one DSTBP# and one DSTBN#. The following table
shows the grouping of data signals to strobes and DBI#.
DSTBN#/
DSTBP#
Data Group
DBI#
D[15:0]#
D[31:16]#
D[47:32]#
D[63:48]#
0
1
2
3
0
1
2
3
Furthermore, the DBI# signals determine the polarity of the data signals.
Each group of 16 data signals corresponds to one DBI# signal. When the
DBI# signal is active, the corresponding data group is inverted and
therefore sampled active high.
DBI[3:0]#
I/O
DBI[3:0]# (Data Bus Inversion) are source synchronous and indicate the polarity of
the D[63:0]# signals. The DBI[3:0]# signals are activated when the data on the data
bus is inverted. If more than half the data bits, within, within a 16-bit group, would
have been asserted electronically low, the bus agent may invert the data bus signals
for that particular sub-phase for that 16-bit group.
3
DBI[3:0]# Assignment to Data Bus
Bus Signal
Data Bus Signals
DBI0#
DBI1#
DBI2#
DBI3#
D[15:0]#
D[31:16]#
D[47:32]#
D[63:48]#
DBR#
O
DBR# is used only in systems where no debug port connector is implemented on the
system board. DBR# is used by a debug port interposer so that an in-target probe
can drive system reset. If a debug port connector is implemented in the system,
DBR# is treated as a no connect for the processor socket. DBR# is not a processor
signal.
DBSY#
I/O
I
DBSY# (Data Bus Busy) is asserted by the agent responsible for driving data on the
processor FSB to indicate that the data bus is in use. The data bus is released after
DBSY# is deasserted. This signal must connect the appropriate pins on all processor
FSB agents.
3
3
DEFER#
DEFER# is asserted by an agent to indicate that a transaction cannot be guaranteed
in-order completion. Assertion of DEFER# is normally the responsibility of the
addressed memory or I/O agent. This signal must connect the appropriate pins of all
processor FSB agents.
DP[3:0]#
DRDY#
I/O
I/O
DP[3:0]# (Data Parity) provide parity protection for the D[63:0]# signals. They are
driven by the agent responsible for driving D[63:0]#, and must connect the
appropriate pins of all processor FSB agents.
3
3
DRDY# (Data Ready) is asserted by the data driver on each data transfer, indicating
valid data on the data bus. In a multi-common clock data transfer, DRDY# may be
deasserted to insert idle clocks. This signal must connect the appropriate pins of all
processor FSB agents.
Dual-Core Intel® Xeon® Processor 5000 Series Datasheet
63
INTEL [ INTEL ]
