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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Develepor’s Manual
Order Number: 306262-004US
543
PCI Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
In a similar manner, the pci_csr.ADS bit controls byte lane routing when an AHB agent
accesses an external PCI device using memory-mapped accesses (no swapping is
performed during the CSR-controlled non-prefetch cycles).
and
illustrate the data routing in AHB big-endian and little-endian modes respectively.
Figure 96.
Byte Lane Routing During PCI Target Accesses of the AHB Bus – Little-Endian
AHB Bus
B4279-01
31
24
Write,
pci_csr.PDS = 1
AHB Data
3
2
1
0
23
16 15
8
7
0
31
24
11
10
01
00
23
16 15
8
7
0
31
24
3
2
1
0
23
16 15
8
7
0
31
24
11
10
01
00
23
16 15
8
7
0
AHB Data
PCI Data
PCI Data
Read,
pci_csr.PDS = 1
31
24
Write,
pci_csr.PDS = 0
AHB Data
3
2
1
0
23
16 15
8
7
0
31
24
11
10
01
00
23
16 15
8
7
0
31
24
3
2
1
0
23
16 15
8
7
0
31
24
11
10
01
00
23
16 15
8
7
0
AHB Data
PCI Data
PCI Data
Read,
pci_csr.PDS = 0