Datasheet

69
Signal Definitions
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.
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#.
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.
3
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
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 a no-
connect on the Dual-Core Intel® Xeon® Processor 5200 Series
package. DBR# is not a processor signal.
DBSY# I/O 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
DEFER# I 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.
3
DP[3:0]# 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
Table 5-1. Signal Definitions (Sheet 3 of 8)
Name Type Description Notes
Data Group
DSTBN#/DST
BP#
DBI#
D[15:0]# 0 0
D[31:16]# 1 1
D[47:32]# 2 2
D[63:48]# 3 3
DBI[3:0] Assignment to Data Bus
Bus Signal Data Bus Signals
DBI0# D[15:0]#
DBI1# D[31:16]#
DBI2# D[47:32]#
DBI3# D[63:48]#