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Table 191.
PCI Memory Map Allocation
Description
First 16-Mbyte window
Second 16-Mbyte window
Third 16-Mbyte window
Fourth 16-Mbyte window
The four 16-Mbyte windows translate their South AHB addresses to the PCI Bus
addresses using the PCI Memory Base Address Register (PCI_PCIMEMBASE).
The PCI Memory Base Address Register (PCI_PCIMEMBASE) register consists of four 8-
bit fields. Each of these fields corresponds to a given 16-Mbyte window:
• Bits 31:24 of the PCI Memory Base Address Register (PCI_PCIMEMBASE) register
correspond to the first 16-Mbyte window from South AHB address 0x48000000 to
0x48FFFFFF
• Bits 23:16 of the PCI Memory Base Address Register (PCI_PCIMEMBASE) register
correspond to the second 16-Mbyte window from South AHB address 0x49000000
to 0x49FFFFFF
• Bits 15:8 of the PCI Memory Base Address Register (PCI_PCIMEMBASE) register
correspond to the third 16-Mbyte window from South AHB address 0x4A000000 to
0x4AFFFFFF
• Bits 7:0 of the PCI Memory Base Address Register (PCI_PCIMEMBASE) register
correspond to the fourth 16-Mbyte window from South AHB address 0x4B000000
to 0x4BFFFFFF.
The PCI Memory Base Address Register (PCI_PCIMEMBASE) register is used to
determine the upper eight PCI address bits when the IXP45X/IXP46X network
processors access the memory spaces of external Targets on the PCI bus.
10.2.4.2
Example: PCI Memory Base Address Register and
South-AHB Translation
The following example discusses the operation of the PCI Memory Base Address
Register (PCI_PCIMEMBASE) and the South AHB translation.
1. Assume that PCI_PCIMEMBASE = 0xC3A24169.
2. The next example shows an access to the first 16-Mbyte window.
The South AHB address is for the access is 0x48123450. The address presented on
the PCI bus is 0xC3123450.
3. The next example shows an access to the second 16-Mbyte window.
The South AHB address is for the access is 0x49123450. The address presented on
the PCI bus is 0xA2123450.
4. The next example shows an access to the third 16-Mbyte window.
The South AHB address is for the access is 0x4A123450. The address presented on
the PCI bus is 0x41123450.
5. The next example shows an access to the fourth 16-Mbyte window.
The South AHB address is for the access is 0x4B123450. The address presented on
the PCI bus is 0x69123450.
®
®
Intel
IXP45X and Intel
IXP46X Product Line of Network Processors
Develepor's Manual
508
®
®
Intel
IXP45X and Intel
Starting Address
0x48000000
0x49000000
0x4A000000
0x4B000000
IXP46X Product Line of Network Processors—PCI Controller
Ending Address
0x48FFFFFF
0x49FFFFFF
0x4AFFFFFF
0x4BFFFFFF
August 2006
Order Number: 306262-004US
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