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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Develepor’s Manual
Order Number: 306262-004US
525
PCI Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
This interface receives the address, word count, byte enables and PCI command type
from the AHB side and performs the specified transaction on the PCI bus, handling all
bus protocol and retry/disconnect situations.
lists the supported transaction
types.
10.3.2.2.1
Initiator Write Transactions
The PCI Master Interface receives write requests from the AHB Slave Interface or AHB-
to-PCI DMA Controller via the Initiator Request FIFO. Write data is supplied using the
Initiator Transmit FIFO. The Master Interface transfers the indicated number of words
from the FIFO to the PCI bus. The following rules apply to the write transfers:
• If the Transmit FIFO becomes empty, the Master Interface terminates the cycle on
the PCI bus. When more data becomes available, the transfer resumes using the
address of the next word to be delivered.
• If the master’s Latency Timer expires, the Master Interface terminates the cycle on
the PCI bus (see
“Master Latency Timer” on page 526
for a description of the
Latency Timer). The transfer resumes at the first opportunity using the address of
the next word to be delivered.
• If a retry or target disconnect is received before the transfer ends, the Master
Interface resumes the transfer at the first opportunity using the address of the next
data word to be delivered.
• If a master abort occurs, all of the write data is discarded and the Received Master
Abort bit is set in the PCI Configuration status register.
• If a target abort is received, all of the write data is discarded and the Received
Target Abort bit is set in the PCI Configuration status register.
Table 196.
PCI Initiator Interface Supported Commands
PCI Byte Enables
Command Type
Support
0x0
Interrupt Acknowledge
supported
0x1
Special Cycle
supported
0x2
I/O Read
supported
0x3
I/O Write
supported
0x4
Reserved
0x5
Reserved
0x6
Memory Read
supported
0x7
Memory Write
supported
0x8
Reserved
0x9
Reserved
0xa
Configuration Read
supported
0xb
Configuration Write
supported
0xc
Memory Read Multiple
supported
0xd
Dual Address Cycle
not supported
0xe
Memory Read Line
supported
0xf
Memory Write and Invalidate
not supported