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4-2
Computer Group Literature Center Web Site
Programming Details
4
PCI Arbitration
PCI arbitration is performed by the PCI-to-ISA Bridge (PIB) which
supports six PCI external PCI masters. The PIB is also a PCI master for
ISA DMA functions. The arbitration assignments on the MTX series are
as follows:
Upon power-up, the PIB defaults to a round-robin arbitration mode. The
relative priority of each request/grant pair can be customized via the PCI
Priority Control Register 1. Refer to the W83C553 Data Book, listed in
Appendix A, Related Documentation
, for additional details.
Table 4-2. PCI Arbitration Assignments
PCI BUS
REQUEST
PCI Master(s)
PIB (internal)
PIB
CPU
Raven ASIC
Request 0
PMC/PCI Slot 2
Request 1
PMC/PCI Slot 1
Request 2
Ethernet
Request 3
SCSI
Request 4
PCI Slot 3