PI7C8150AMAE Pericom Semiconductor, PI7C8150AMAE Datasheet - Page 26

• Manufacturer Part Number: PI7C8150AMAE
• Description: IC PCI-PCI BRIDGE 2PORT 208-FQFP
• Manufacturer: Pericom Semiconductor

Specifications of PI7C8150AMAE

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

06-0057
3.5.4
3.5.5
3.5.6
Table 3-3. Write Transaction Disconnect Address Boundaries
PI7C8150A implements a discard timer that starts counting when the delayed write
completion is at the head of the delayed transaction completion queue. The initial value of
this timer can be set to the retry counter register offset 78h.
If the initiator does not repeat the delayed write transaction before the discard timer
expires, PI7C8150A discards the delayed write completion from the delayed transaction
completion queue. PI7C8150A also conditionally asserts P_SERR_L (see Section 6.4).
WRITE TRANSACTION ADDRESS BOUNDARIES
PI7C8150A imposes internal address boundaries when accepting write data. The aligned
address boundaries are used to prevent PI7C8150A from continuing a transaction over a
device address boundary and to provide an upper limit on maximum latency. PI7C78150A
returns a target disconnect to the initiator when it reaches the aligned address boundaries
under conditions shown in Table 3-3.
BUFFERING MULTIPLE WRITE TRANSACTIONS
PI7C8150A continues to accept posted memory write transactions as long as space for at
least one DWORD of data in the posted write data buffer remains. If the posted write data
buffer fills before the initiator terminates the write transaction, PI7C8150A returns a target
disconnect to the initiator.
Delayed write transactions are posted as long as at least one open entry in the delayed
transaction queue exists. Therefore, several posted and delayed write transactions can exist
in data buffers at the same time. See Chapter 6 for information about how multiple posted
and delayed write transactions are ordered.
FAST BACK-TO-BACK TRANSACTIONS
PI7C8150A can recognize and post fast back-to-back write transactions. When
PI7C8150A cannot accept the second transaction because of buffer space limitations, it
returns a target retry to the initiator. The fast back-to-back enable bit must be set in the
command register for upstream write transactions, and in the bridge control register for
downstream write transactions.
Note 1. Memory write disconnect control bit is bit 1 of the chip control register at offset 40h in the
configuration space.
Type of Transaction
Delayed Write
Posted Memory Write
Posted Memory Write
Posted Memory Write and
Invalidate
Posted Memory Write and
Invalidate
bit = 0
Condition
All
Memory write disconnect control
Memory write disconnect control
bit = 1
Cache line size ≠ 1, 2, 4, 8, 16
Cache line size = 1, 2, 4, 8, 16
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(1)
(1)
2-PORT PCI-TO-PCI BRIDGE
Aligned Address Boundary
Disconnects after one data transfer
4KB aligned address boundary
Disconnects at cache line boundary
4KB aligned address boundary
Cache line boundary if posted memory
write data FIFO does not have enough
space for the cache line
APRIL 2006 – Revision 1.1
PI7C8150A