pi7c8150b Pericom Semiconductor Corporation, pi7c8150b Datasheet - Page 40

• Manufacturer Part Number: pi7c8150b
• Description: Asynchronous 2-port Pci Bridge
• Manufacturer: Pericom Semiconductor Corporation

06-0044
3.8.4.3
4
4.1
4.2
See Section 3.5.4 for a description of write address boundaries, and Section 3.6.3 for a
description of read address boundaries.
TARGET ABORT
PI7C8150B returns a target abort to an initiator when one of the following conditions is
met:
ADDRESS DECODING
PI7C8150B uses three address ranges that control I/O and memory transaction forwarding.
These address ranges are defined by base and limit address registers in the configuration
space. This chapter describes these address ranges, as well as ISA-mode and VGA-
addressing support.
ADDRESS RANGES
PI7C8150B uses the following address ranges that determine which I/O and memory
transactions are forwarded from the primary PCI bus to the secondary PCI bus, and from
the secondary bus to the primary bus:
Transactions falling within these ranges are forwarded downstream from the primary PCI
bus to the secondary PCI bus. Transactions falling outside these ranges are forwarded
upstream from the secondary PCI bus to the primary PCI bus.
No address translation is required in PI7C8150B. The addresses that are not marked for
downstream are always forwarded upstream.
I/O ADDRESS DECODING
PI7C8150B uses the following mechanisms that are defined in the configuration space to
specify the I/O address space for downstream and upstream forwarding:
PI7C8150B cannot accept any more write data.
PI7C8150B has no more read data to deliver.
PI7C8150B is returning a target abort from the intended target.
When PI7C8150B returns a target abort to the initiator, it sets the signaled target abort
bit in the status register corresponding to the initiator interface.
Two 32-bit I/O address ranges
Two 32-bit memory-mapped I/O (non-prefetchable memory) ranges
Two 32-bit prefetchable memory address ranges
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ASYNCHRONOUS 2-PORT PCI-TO-PCI BRIDGE
APRIL 2006 – Revision 2.02
PI7C8150B