RAM5006E-016 Emerson Network Power, RAM5006E-016 Datasheet - Page 99

• Manufacturer Part Number: RAM5006E-016
• Manufacturer: Emerson Network Power

Specifications of RAM5006E-016

• Lead Free Status / RoHS Status: Compliant

Table 7-5. Devices Affected by Various Resets
Endian Issues
Processor/Memory Domain
Power-On reset
Reset switch
Watchdog reset
VME
SYSRESET∗signal
VME System SW
reset
VME Local SW reset
VME CSR reset
Hot reset (Port 92)
PCI/ISA reset
The MVME5100 supports both little-endian (e.g., Windows NT) and big-endian (e.g., AIX)
software. The PowerPC processor and the VMEbus are inherently big-endian, while the PCI
bus is inherently little-endian. The following sections summarize how the MVME5100 handles
software and hardware differences in big- and little-endian operations. For further details on
endian considerations, refer to the MVME5100-Series Single Board Computer Programmer’s
Reference Guide.
The MPC750 processor can operate in both big-endian and little-endian mode. However, it
always treats the external processor/memory bus as big-endian by performing address
rearrangement and reordering when running in little-endian mode. The MPC registers in the
Hawk MPU/PCI bus bridge controller, SMC memory controller, as well as DRAM, Flash and
system registers, always appear as big-endian.
Role of the Hawk ASIC
Because the PCI bus is little-endian, the PHB portion of the Hawk 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 PHB 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.
Device Affected
Reset Source
MVME51005E Single Board Computer Installation and Use (6806800A38B)
√
√
√
√
√
√
√
√
Proces
sor
√
√
√
√
√
√
√
√
Hawk
ASIC
√
√
√
√
√
√
√
√
√
Devices
PCI
√
√
√
√
√
√
√
√
√
Devices
ISA
7 Programming the MVME5100
√
√
√
√
√
(as system
controller)
VMEbus
81