59
PEB383 User Manual
July 25, 2011
Integrated Device Technology, Inc.
Confidential - NDA Required
7. PCI
Arbitration
Topics discussed include the following:
•
•
•
7.1
Overview
The PCI internal bus arbiter manages access to the PCI bus for up to five requesters, including the
PEB383. The bus arbiter has the following features:
•
Supports five requests (four external and one internal, the PEB383)
•
Can be programmed to give high and low priorities for requesters
•
Bus is parked on latest master given grant
7.2
Block Diagram
The bus arbiter handles internal requests from the PCI Core and external requests from devices on the
PCI bus (see
). When the arbiter is enabled, the PEB383 asserts the grant for PCI devices and
for the PCI Core. When the arbiter is disabled, there must be an external arbiter on the PCI bus that
handles PEB383 requests through the PCI_REQ[0]n signal, and grants bus access using the
PCI_GNT[0] signal.
Grants and Requests are bi-directional pins. PCI_REQ[0]n is output enabled when the internal arbiter
is disabled. Enable of PCI_REQ[3:1]n are always hardcoded to 1’h0. PCI_GNT[0] is an input pin
when the internal arbiter is disabled.
Figure 17: PCI Arbiter Block Diagram