Functional Description
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Functional Description
MPC Bus Interface
The MPC Bus Interface is designed to be coupled directly to up to two
MPC601, MPC603, or MPC604 microprocessors as well as a
memory/cache subsystem. It uses a subset of the capabilities of the
MPC60x bus protocol.
MPC Arbiter
The MPC Arbiter is an optional feature in the Raven. The Raven MPC
Arbiter is enabled if both CPUID pins are sampled high on the rising edge
of RST*. When this feature is enabled, the MARB bit in the General
Control/Status Register (GCSR) will be set. When this feature is not
enabled, the MARB bit will be cleared and the Raven will be configured
for external arbitration.
The MPC Arbiter function is responsible for determining address bus
ownership. The MPC Arbiter function does not provide data bus
arbitration. Determining data bus ownership is the responsibility of each
MPC master and follows the ownership ordering established on the
address bus.
The MPC Arbiter supports a total of four participants. One participant is
the Raven MPC master function, which represents PCI initiated MPC
transactions. The remaining three participants are external to the Raven,
and are represented as request/grant signal pairs.
The MPC Arbiter supports a mixture of Fixed Priority and Round-Robin
Priority arbitration schemes. PCI initiated transactions will always have
the highest priority over all external requests. The external requests will be
honored in a Round-Robin algorithm. This algorithm enforces fairness for
bus ownership by assigning the lowest priority to the most recently granted
bus requester. If a bus requester is not granted bus ownership during an
arbitration event, the priority of that requester will be increased for the next
arbitration event.
Содержание MVME2700 Series
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Страница 70: ...Introduction 2 3 2 Four 31 bit tick timers Two 64 bit general purpose registers for cross processor messaging ...
Страница 151: ...2 84 Raven PCI Host Bridge Multi Processor Interrupt Controller Chip 2 ...
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