MVME5100 Single Board Computer Programmer's Reference Guide

2
Hawk PCI Host Bridge & Multi-Processor Interrupt Controller
PCI Slave
MPIC Control Registers
The MPIC control registers are located within either PCI Memory or PCI
I/O space using traditional PCI defined base registers within the predefined
64-byte header. Refer to the section titled Multi-Processor Interrupt
Controller (MPIC) for more information.
The PCI Slave provides the control logic needed to interface the PCI bus
to the PCI FIFO. The PCI Slave can accept either 32-bit or 64-bit
transactions; however, it can only accept 32-bit addressing. There is no
limit to the length of the transfer that the PCI Slave can handle. During
posted write cycles, the PCI Slave will continue to accept write data until
the PCI FIFO is full. If the PCI FIFO is full, the PCI Slave will hold off the
master with wait states until there is more room in the FIFO. The PCI Slave
will not initiate a disconnect. If the write transaction is compelled, the PCI
Slave will hold off the master with wait states while each beat of data is
being transferred. The PCI Slave issues TRDY_ only after the data transfer
has successfully completed on the PPC bus. If a read transaction is being
performed within an address space marked for prefetching, the PCI Slave
(in conjunction with the PPC Master) attempts to read ahead far enough on
the PPC bus to allow for an uninterrupted burst transaction on the PCI bus.
Read transactions within address spaces marked for no prefetching receive
a TRDY_ indication on the PCI bus only after one burst read has
successfully completed on the PPC bus. Each read on the PPC bus is only
started after the previous read is acknowledged on the PCI bus and there is
an indication that the PCI Master wishes for more data to be transferred.
The following paragraphs identify some associations between the
operation of the PCI slave and the PCI 2.1 Local Bus Specification
requirements.
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