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Universe (VMEbus to PCI) Chip

Universe as PCI Slave

Read transactions from the PCI bus are always processed as coupled. Write transactions may be either coupled or posted, depending upon the setting of the PCI bus slave image. (Refer to PCI Bus Slave Images in the Universe User Manual.) With a posted write transaction, write data is written to a Posted Write Transmit FIFO (TXFIFO) and the PCI bus master receives data acknowledgment from the Universe with zero wait states. Meanwhile, the Universe obtains the VMEbus and writes the data to the VMEbus resource independent of the initiating PCI master. (Refer to Posted Writes in the Universe User Manual for a full description of this operation.)

To allow PCI masters to perform RMW and ADOH cycles, the Universe provides a Special Cycle Generator. The Special Cycle Generator can be used in combination with a VMEbus ownership function to guarantee PCI masters exclusive access to VMEbus resources over several VMEbus transactions. (Refer to Exclusive Accesses and RMW and ADOH Cycles in the Universe User Manual for a full description of this functionality.)

Universe as PCI Master

The Universe becomes PCI master when the PCI Master Interface is internally requested by the VME Slave Channel or the DMA Channel. There are mechanisms provided which allow the user to configure the relative priority of the VME Slave Channel and the DMA Channel.

Interrupter

The Universe interrupt channel provides a flexible scheme to map interrupts to either the PCI bus or VMEbus interface. Interrupts are generated from either hardware or software sources (refer to the Interrupter section of the Universe User Manual for a full description of hardware and software sources). Interrupt sources can be mapped to any of the PCI bus or VMEbus interrupt output pins. Interrupt sources mapped to VMEbus interrupts are generated on the VMEbus interrupt output pins VIRQ∗[7:1]. When a software and hardware source are assigned the same VIRQn∗ pin, the software source always has higher priority.

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Computer Group Literature Center Web Site

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Motorola MVME2300 Series manual Interrupter, Universe as PCI Slave Universe as PCI Master