PI7C8150BMAIE Pericom Semiconductor, PI7C8150BMAIE Datasheet - Page 33

• Manufacturer Part Number: PI7C8150BMAIE
• Description: IC PCI-PCI BRIDGE ASYNC 208-FQFP
• Manufacturer: Pericom Semiconductor

Specifications of PI7C8150BMAIE

• Applications: *
• Interface: *
• Voltage - Supply: *
• Package / Case: 208-FQFP
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3.7.3
PI7C8150B can assert up to 9 unique address lines to be used as IDSEL signals for
up to 9 devices on the secondary bus, for device numbers ranging from 0 through 8.
Because of electrical loading constraints of the PCI bus, more than 9 IDSEL signals should
not be necessary. However, if device numbers greater than 9 are desired, some external
method of generating IDSEL lines must be used, and no upper address bits are then
asserted. The configuration transaction is still translated and passed from the primary bus to
the secondary bus. If no IDSEL pin is asserted to a secondary device, the transaction ends
in a master abort.
PI7C8150B forwards Type 1 to Type 0 configuration read or write transactions as delayed
transactions. Type 1 to Type 0 configuration read or write transactions are limited to a
single 32-bit data transfer.
TYPE 1 TO TYPE 1 FORWARDING
Type 1 to Type 1 transaction forwarding provides a hierarchical configuration mechanism
when two or more levels of PCI-to-PCI bridges are used.
When PI7C8150B detects a Type 1 configuration transaction intended for a PCI bus
downstream from the secondary bus, PI7C8150B forwards the transaction unchanged to the
secondary bus. Ultimately, this transaction is translated to a Type 0 configuration command
or to a special cycle transaction by a downstream PCI-to-PCI bridge. Downstream Type 1
to Type 1 forwarding occurs when the following conditions are met during the address
phase:
PI7C8150B also supports Type 1 to Type 1 forwarding of configuration write transactions
upstream to support upstream special cycle generation. A Type 1 configuration command
is forwarded upstream when the following conditions
are met:
Device Number
1Fh
The lowest two address bits are equal to 01b.
The bus number falls in the range defined by the lower limit (exclusive) in the
secondary bus number register and the upper limit (inclusive) in the subordinate bus
number register.
The bus command is a configuration read or write transaction.
The lowest two address bits are equal to 01b.
The bus number falls outside the range defined by the lower limit (inclusive) in the
secondary bus number register and the upper limit (inclusive) in the subordinate bus
number register.
The device number in address bits AD[15:11] is equal to 11111b.
The function number in address bits AD[10:8] is equal to 111b.
The bus command is a configuration write transaction.
P_AD[15:11]
11111
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ASYNCHRONOUS 2-PORT PCI-TO-PCI BRIDGE
Secondary IDSEL S_AD[31:16]
Generate special cycle (P_AD[7:2] > 00h)
0000 0000 0000 0000 (P_AD[7:2] = 00h)
ADVANCE INFORMATION
April 2009 – Revision 1.08
PI7C8150B
S_AD
-