Intel® IXP42X product line and IXC1100 control plane processors—PCI Controller
Intel® IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
DM September 2006
244 Order Number: 252480-006US
In a similar fashion — as described for PCI Target accesses directed towards the IXP42X product line and IXC1100 control plane processors — bit 2 (AHB Memory Mapped Byte Swap) of the PCI Controller Control and Status Register (PCI_CSR) controls byte-lane routing when an AHB agent accesses an external PCI device using memory-mapped accesses (0x48000000 to 0x4BFFFFFF). Figure 49 and Figure 50 illustrate the data routing when the AHB is configured as big endian and little-endian modes.Figure 48. Byte Lane Routing During PCI Target Accesses of the AHB – AHB Configured as a Little-Endian Bus
31 24
Write,
pci_csr.PDS = 1
AHB Data
3210
23 16 15 870
31 24
11 10 01 00
23 16 15 870
31 24
3 2 10
23 16 15 870
31 24
11 10 01 00
23 16 15 870
AHB Data
PCI Data PCI Data
Read,
pci_csr.PDS = 1
31 24
Write,
pci_csr.PDS = 0
AHB Data
3210
23 16 15 870
31 24
11 10 01 00
23 16 15 870
31 24
3 2 10
23 16 15 870
31 24
11 10 01 00
23 16 15 870
AHB Data
PCI Data PCI Data
Read,
pci_csr.PDS = 0