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Raven PCI Bridge ASIC

PCI Slave

The PCI slave provides the control logic needed to interface the PCI bus to the Raven’s FIFO buffers. The PCI slave can accept either 32-bit or 64-bit transactions, but it can accept only 32-bit addressing.

There is no limit to the length of the transfer that the slave can handle. During posted write cycles, the slave will continue to accept write data until the write-post FIFO is full. If the write-post FIFO is full, the slave will hold off the master with wait states until there is more room in the FIFO. The slave will not initiate a disconnect.

If the write transaction is compelled, the slave will hold off the master with wait states while each beat of data is being transferred. The slave will acknowledge the completion of the transfer only after the data transfer has successfully completed on the MPC bus.

If a read transaction is occurring within an address space marked for prefetching, the slave (in conjunction with the MPC master) will attempt to read far enough ahead on the MPC bus to allow for an uninterrupted burst transaction on the PCI bus. Read transactions within address spaces marked for no prefetching will be acknowledged on the PCI bus only after a single beat read has successfully completed on the MPC bus.

Each read on the MPC bus will begin only after the previous read has been acknowledged on the PCI bus and there is an indication that the PCI master wishes more data to be transferred.

The following paragraphs identify some associations between the operation of the PCI slave and the requirements of the PCI 2.0 Local Bus Specification.

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Motorola MVME2300 Series manual PCI Slave