Motorola MVME2300 Series - Manual (Page 245)

5-1
5
5 Programming Details
Introduction
This chapter discusses details of several programming functions that are
not tied to any specific ASIC chip.
PCI Arbitration
PCI arbitration is performed by the PCI-to-ISA Bridge (PIB) which
supports six PCI external PCI masters. The PIB can also be a PCI master
for ISA DMA functions. The arbitration assignments on the MVME2300
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 PCI
Priority Control Register 1. Refer to the W83C553 Data Book for
additional details, in
Appendix A, Related Documentation .
Table 5-1. PCI Arbitration Assignments
Pci Bus Request PCI Master(s)
PIB (internal) PIB
CPU Raven ASIC
Request 0 PMC Slot 2
Request 1 PMC Slot 1
Request 2 PCIX Slot
Request 3 Ethernet
Request 4 Universe ASIC (VMEbus)