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Role of the Raven ASIC
Because the PCI bus is little-endian, the Raven performs byte swapping in
both directions (from PCI to memory and from the processor to PCI) to
maintain address invariance while programmed to operate in big-endian
mode with the processor and the memory subsystem.
In little-endian mode, the Raven reverse-rearranges the address for PCI-
bound accesses and rearranges the address for memory-bound accesses
(from PCI). In this case, no byte swapping is done.
PCI Domain
The PCI bus is inherently little-endian. All devices connected directly to
the PCI bus operate in little-endian mode, regardless of the mode of
operation in the processor’s domain.
PCI and Ethernet
Ethernet is also byte-stream-oriented; the byte having the lowest address
in memory is the first one to be transferred regardless of the endian mode.
Since the Raven maintains address invariance in both little-endian and big-
endian mode, no endian issues should arise for Ethernet data. Big-endian
software must still take the byte-swapping effect into account when
accessing the registers of the PCI/Ethernet device, however.
Summary of Contents for MCPN750A
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Page 53: ...1 32 Computer Group Literature Center Web Site Hardware Preparation and Installation 1 ...
Page 67: ...2 14 Computer Group Literature Center Web Site Startup and Operation 2 ...
Page 105: ...5 14 Computer Group Literature Center Web Site Remote Start Via the PCI Bus 5 ...
Page 167: ...7 38 Computer Group Literature Center Web Site Connector Pin Assignments 7 ...
Page 171: ...A 4 Computer Group Literature Center Web Site Specifications A ...
Page 187: ...Index IN 10 Computer Group Literature Center Web Site I N D E X ...