450NX Datasheet, PDF (18/248 Pages) Intel Corporation – Intel 450NX PCIset

2. Signal Descriptions
2.3
System Interface
The MIOC provides the Intel^® 450NX PCIset’s sole connection to the system bus. This section
describes the Intel 450NX PCIset-specific uses of these signals.
2.3.1
System / MIOC Interface
A[35:3]#
ADS#
AERR#
AP[1:0]#
BERR#
BINIT#
BNR#
BP[1:0]#
BPRI#
BREQ[0]#
Address Bus
AGTL+ I/O
A[35:3]# connect to the system address bus. During processor cycles the
A[35:3]# are inputs. The MIOC drives A[35:3]# during snoop cycles on behalf
of PCI initiators. The address bus is inverted on the system bus.
Address Strobe
AGTL+ I/O
The system bus owner asserts ADS# to indicate the first of two cycles of a
request phase.
Address Parity Error
AGTL+ I/O
AERR# is asserted by any agent that detects an address parity error.
Address Parity
AGTL+ I/O
Parity protection on the address bus. AP#[1] covers A#[35:24], and AP#[0]
covers A#[23:3]. They are valid on both cycles of the request.
Bus Error
AGTL+ I/O
This signal is asserted by any agent that observes an unrecoverable bus
protocol violation.
Bus Initialization
AGTL+ I/O
BINIT# is asserted to re-initialize the bus state machines. The MIOC will
terminate any ongoing PCI transaction and reset its inbound and outbound
queues. No configuration registers or error logging registers are affected.
Block Next Request
AGTL+ I/O
Used to block the current request bus owner from issuing a new request.
Performance Monitoring
LVTTL I/OD
In normal operation, the MIOC can be configured to drive performance
monitoring data out of either of these pins, similar in function to the BP pins
provided on the processors.
Priority Agent Bus Request
AGTL+ O
The MIOC is the only Priority Agent on the system bus. It asserts this signal
to obtain ownership of the address bus. BPRI# has priority over symmetric
bus requests.
Symmetric Agent Bus Request
AGTL+ O
This signal is asserted by the MIOC when RESET# is asserted, to select the
boot processor. It is deasserted 2 host clocks after RESET# is deasserted.
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Intel® 450NX PCIset