Intel E5205 - Cpu Xeon 1.86Ghz Fsb1066Mhz 6M Lga771 Dual Core Tray Datasheet page 68

Table 5-1. Signal Definitions (Sheet 2 of 8)
Name
BCLK[1:0]
BINIT#
BNR#
BPM5#
BPM4#
BPM3#
BPM[2:1]#
BPM0#
BPRI#
BR[1:0]#
BSEL[2:0]
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Type
I The differential bus clock pair BCLK[1:0] (Bus Clock) determines the
FSB frequency. All processor FSB agents must receive these signals
to drive their outputs and latch their inputs.
All external timing parameters are specified with respect to the rising
edge of BCLK0 crossing V
I/O BINIT# (Bus Initialization) may be observed and driven by all
processor FSB agents and if used, must connect the appropriate pins
of all such agents. If the BINIT# driver is enabled during power on
configuration, BINIT# is asserted to signal any bus condition that
prevents reliable future operation.
If BINIT# observation is enabled during power-on configuration (see
Section 7.1) and BINIT# is sampled asserted, symmetric agents
reset their bus LOCK# activity and bus request arbitration state
machines. The bus agents do not reset their I/O Queue (IOQ) and
transaction tracking state machines upon observation of BINIT#
assertion. Once the BINIT# assertion has been observed, the bus
agents will re-arbitrate for the FSB and attempt completion of their
bus queue and IOQ entries.
If BINIT# observation is disabled during power-on configuration, a
priority agent may handle an assertion of BINIT# as appropriate to
the error handling architecture of the system.
I/O BNR# (Block Next Request) is used to assert a bus stall by any bus
agent who is unable to accept new bus transactions. During a bus
stall, the current bus owner cannot issue any new transactions.
Since multiple agents might need to request a bus stall at the same
time, BNR# is a wired-OR signal which must connect the appropriate
pins of all processor FSB agents. In order to avoid wired-OR glitches
associated with simultaneous edge transitions driven by multiple
drivers, BNR# is activated on specific clock edges and sampled on
specific clock edges.
I/O BPM[5:0]# (Breakpoint Monitor) are breakpoint and performance
monitor signals. They are outputs from the processor which indicate
O
the status of breakpoints and programmable counters used for
I/O
monitoring processor performance. BPM[5:0]# should connect the
O
appropriate pins of all FSB agents.
I/O
BPM4# provides PRDY# (Probe Ready) functionality for the TAP port.
PRDY# is a processor output used by debug tools to determine
processor debug readiness.
BPM5# provides PREQ# (Probe Request) functionality for the TAP
port. PREQ# is used by debug tools to request debug operation of the
processors.
BPM[5:4]# must be bussed to all bus agents. Please refer to the
appropriate platform design guidelines for more detailed information.
I BPRI# (Bus Priority Request) is used to arbitrate for ownership of the
processor FSB. It must connect the appropriate pins of all processor
FSB agents. Observing BPRI# active (as asserted by the priority
agent) causes all other agents to stop issuing new requests, unless
such requests are part of an ongoing locked operation. The priority
agent keeps BPRI# asserted until all of its requests are completed,
then releases the bus by deasserting BPRI#.
I/O The BR[1:0]# signals are sampled on the active-to-inactive transition
of RESET#. The signal which the agent samples asserted determines
its agent ID. BR0# drives the BREQ0# signal in the system and is
used by the processor to request the bus.
These signals do not have on-die termination and must be
terminated.
O The BCLK[1:0] frequency select signals BSEL[2:0] are used to select
the processor input clock frequency.
combinations of the signals and the frequency associated with each
combination. The required frequency is determined by the
processors, chipset, and clock synthesizer. All FSB agents must
operate at the same frequency. For more information about these
signals, including termination recommendations, refer to the
appropriate platform design guideline.
Description
.
CROSS
Table 2-2 defines the possible
Signal Definitions
Notes
3
3
3
2
3
3