Motorola MVME2400 Series Wartungshandbuch PDF herunterladen (Seite 65)

Functional Description

http://www.mcg.mot.com/literature 2-7

Each map decoder also includes a programmable 16-bit address offset. The

offset is added to the 16 most significant bits of the PPC address, and the

result is used as the PCI address. This offset allows PCI devices to reside

at any PCI address, independent of the PPC address map. An example of

this is shown in Figure 2-3.

Figure 2-3. PPC to PCI Address Translation

Care should be taken to assure that all programmable decoders decode

unique address ranges since overlapping address ranges will lead to

undefined operation.

PPC Slave

The PPC slave provides the interface between the PPC bus and the PPC

FIFO. The PPC slave is responsible for tracking and maintaining

coherency to the PPC60x processor bus protocol. The actions taken by the

PPC Slave to service a transaction are dependent upon whether the

transaction is posted or compelled. During compelled transactions, such as

a read or a non-posted single beat write, the PPC Slave will hold off

asserting AACK_ and TA_ until after the transaction has completed on the

PCI bus. This has the effect of removing all levels of pipelining during

compelled PHB accesses. The interdependency between the assertion of

PPC Bus Address

0801234

16150

XSOFFx Register

000

150

PCI Bus Address

0801234

151631

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Motorola MVME2400 Series Wartungshandbuch Seite 65