Custom PCI timing budgets for Spartan-3 Generation FPGAs

The PCI Local Bus Specification, Revision 3.0 (the PCI specification), defines two timing budgets. One timing budget is for use with 33MHz operation, and the other timing budget is for use with 66MHz operation. These two timing budgets define the I/O timing parameters for compliant 33MHz and 66MHz components.

In open systems, compliance with the PCI specification is a requirement to ensure interoperability. However, in embedded designs, it is possible to create custom timing budgets that enable system designers to do one or more of the following:

? Reduce total system cost by using less expensive devices

? Achieve higher data transfer rates than allowed by specification

? Add more loads to the bus to accommodate additional devices and connectors

? Increase the physical length of the bus to accommodate novel bus topologies.

View the PDF document for more information.