PI7C8150ANDE Pericom Semiconductor, PI7C8150ANDE Datasheet - Page 42
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PI7C8150ANDE
Manufacturer Part Number
PI7C8150ANDE
Description
IC PCI-PCI BRIDGE 2PORT 256-PBGA
Manufacturer
Pericom Semiconductor
Datasheet
1.PI7C8150ANDE.pdf
(111 pages)
Specifications of PI7C8150ANDE
Applications
*
Interface
*
Voltage - Supply
*
Package / Case
256-PBGA
Mounting Type
Surface Mount
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
PI7C8150A
2-PORT PCI-TO-PCI BRIDGE
will be ignored if the I/O enable bit is not set. To enable upstream forwarding of I/O
transactions, the master enable bit must be set in the command register. If the master-
enable bit is not set, PI7C8150A ignores all I/O and memory transactions initiated on the
secondary bus.
The master-enable bit also allows upstream forwarding of memory transactions if it is set.
CAUTION
If any configuration state affecting I/O transaction forwarding is changed by a
configuration write operation on the primary bus at the same time that I/O transactions are
ongoing on the secondary bus, PI7C8150A response to the secondary bus I/O transactions
is not predictable. Configure the I/O base and limit address registers, ISA enable bit, VGA
mode bit, and VGA snoop bit before setting I/O enable and master enable bits, and change
them subsequently only when the primary and secondary PCI buses are idle.
4.2.1
I/O BASE AND LIMIT ADDRESS REGISTER
PI7C8150A implements one set of I/O base and limit address registers in configuration
space that define an I/O address range per port downstream forwarding. PI7C8150A
supports 32-bit I/O addressing, which allows I/O addresses downstream of PI7C8150A to
be mapped anywhere in a 4GB I/O address space.
I/O transactions with addresses that fall inside the range defined by the I/O base and limit
registers are forwarded downstream from the primary PCI bus to the secondary PCI bus.
I/O transactions with addresses that fall outside this range are forwarded upstream from the
secondary PCI bus to the primary PCI bus.
The I/O range can be turned off by setting the I/O base address to a value greater than that
of the I/O limit address. When the I/O range is turned off, all I/O trans-actions are
forwarded upstream, and no I/O transactions are forwarded downstream. The I/O range has
a minimum granularity of 4KB and is aligned on a 4KB boundary. The maximum I/O
range is 4GB in size. The I/O base register consists of an 8-bit field at configuration
address 1Ch, and a 16-bit field at address 30h. The top 4 bits of the 8-bit field define bits
[15:12] of the I/O base address. The bottom 4 bits read only as 1h to indicate that
PI7C8150A supports 32-bit I/O addressing. Bits [11:0] of the base address are assumed to
be 0, which naturally aligns the base address to a 4KB boundary. The 16 bits contained in
the I/O base upper 16 bits register at configuration offset 30h define AD[31:16] of the I/O
base address. All 16 bits are read/write. After primary bus reset or chip reset, the value
of the I/O base address is initialized to 0000 0000h.
The I/O limit register consists of an 8-bit field at configuration offset 1Dh and a 16-bit field
at offset 32h. The top 4 bits of the 8-bit field define bits [15:12] of the I/O limit address.
The bottom 4 bits read only as 1h to indicate that 32-bit I/O addressing is supported. Bits
[11:0] of the limit address are assumed to be FFFh, which naturally aligns the limit address
to the top of a 4KB I/O address block. The 16 bits contained in the I/O limit upper 16 bits
register at configuration offset 32h define AD[31:16] of the I/O limit address. All 16 bits
are read/write. After primary bus reset or chip reset, the value of the I/O limit address is
reset to 0000 0FFFh.
Note: The initial states of the I/O base and I/O limit address registers define an I/O range
of 0000 0000h to 0000 0FFFh, which is the bottom 4KB of I/O space. Write these registers
Page 42 of 111
APRIL 2006 – Revision 1.1
06-0057