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A-6
SIGNALS REFERENCE
For Deferred Reply, Interrupt Acknowledge, and Branch Trace Message transactions, the
BE[7:0]# signals are undefined.
A.1.10. BERR# (I/O)
The BERR# signal is the Error group Bus Error signal. It is asserted to indicate an unrecoverable
error without a bus protocol violation.
The BERR# protocol is as follows: If an agent detects an unrecoverable error for which BERR#
is a valid error response and BERR# is sampled inactive, it asserts BERR# for three clocks. An
agent can assert BERR# only after observing that the signal is inactive. An agent asserting
BERR# must deassert the signal in two clocks if it observes that another agent began asserting
BERR# in the previous clock.
BERR# assertion conditions are defined by the system configuration. Configuration options en-
able the BERR# driver as follows:
•
enabled or disabled
•
asserted optionally for internal errors along with IERR#
•
optionally asserted by the request initiator of a bus transaction after it observes an error
•
asserted by any bus agent when it observes an error in a bus transaction
BERR# sampling conditions are also defined by the system configuration. Configuration op-
tions enable the BERR# receiver to be enabled or disabled. When the bus agent samples an ac-
tive BERR# signal and if MCE is enabled, the Pentium Pro processor enters the Machine Check
Handler. If MCE is disabled, typically the central agent forwards BERR# as an NMI to one
of the processors. The Pentium Pro processor does not support BERR# sampling (always
disabled).
A.1.11. BINIT# (I/O)
The BINIT# signal is the bus initialization signal. If the BINIT# driver is enabled during the
power on configuration, BINIT# is asserted to signal any bus condition that prevents reliable fu-
ture information.
The BINIT# protocol is as follows: If an agent detects an error for which BINIT# is a valid error
response, and BINIT# is sampled inactive, it asserts BINIT# for three clocks. An agent can as-
sert BINIT# only after observing that the signal is inactive. An agent asserting BINIT# must
deassert the signal in two clocks if it observes that another agent began asserting BINIT# in the
previous clock.
If BINIT# observation is enabled during power-on configuration, and BINIT# is sampled assert-
ed, all bus state machines are reset. All agents reset their rotating ID for bus arbitration to the
state after reset, and internal count information is lost. The L1 and L2 caches are not affected.
If BINIT# observation is disabled during power-on configuration, BINIT# is ignored by all bus
agents except a central agent that must handle the error in a manner appropriate to the system
architecture.
Summary of Contents for Pentium Pro Family
Page 17: ...1 Component Introduction ...
Page 26: ...2 Pentium Pro Processor Architecture Overview ...
Page 27: ......
Page 36: ...3 Bus Overview ...
Page 62: ...4 Bus Protocol ...
Page 105: ...5 Bus Transactions and Operations ...
Page 126: ...6 Range Registers ...
Page 131: ...7 Cache Protocol ...
Page 135: ...8 Data Integrity ...
Page 148: ...9 Configuration ...
Page 161: ...10 Pentium Pro Processor Test Access Port TAP ...
Page 172: ...11 Electrical Specifications ...
Page 201: ...12 GTL Interface Specification ...
Page 229: ...13 3 3V Tolerant Signal Quality Specifications ...
Page 233: ...14 Thermal Specifications ...
Page 239: ...15 Mechanical Specifications ...
Page 241: ...15 2 MECHANICAL SPECIFICATIONS s Figure 15 1 Package Dimensions Bottom View ...
Page 252: ...16 Tools ...
Page 260: ...16 8 TOOLS Figure 16 4 Generic MP System Layout for Debug Port Connection ...
Page 264: ...17 OverDrive Processor Socket Specification ...
Page 290: ...A Signals Reference ...
Page 320: ...Index ...
Page 328: ......