Motorola MVME2400 Series Wartungshandbuch PDF herunterladen (Seite 86)

2-28 Computer Group Literature Center Web Site

Hawk PCI Host Bridge & Multi-Processor Interrupt Controller

Arbitration:

The PCI Master can support parking on the PCI bus. There are two cases

where the PCI Master continuously asserts its request.

❏ If the PCI Master starts a transaction that is going to take more than

one assertion of FRAME_, the PCI Master continuously asserts its

request until the transaction has completed. For example, the PCI

Master continuously asserts requests during the first part of a two

part critical word first transaction.

❏ If at least one command is pending within the PPC FIFO.

The PCI Master always removes its request when it receives a disconnect

or a retry.

There is a case where the PCI Master could assert a request but not actually

perform a bus cycle. This may happen if the PCI Master is placed in the

speculative request mode. Refer to the section titled PCI/PPC Contention

Handling for more information. In no case will the PCI Master assert its

request for more than 16 clocks without starting a transaction.

Fast Back-to-Back Transactions:

The PCI Master does not generate fast back-to-back transactions.

Arbitration Latency:

Because a bulk of the transactions are limited to single-beat transfers on

PCI, the PCI Master does not implement a Master Latency Timer.

Exclusive Access:

The PCI Master is not able to initiate exclusive access transactions.

Address/Data Stepping:

The PCI Master does not participate in the Address/Data Stepping

protocol.

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Motorola MVME2400 Series Wartungshandbuch Seite 86