XC5200

This application note covers several related subjects: How does a Xilinx FPGA power up, and how does it react to power supply glitches? What can be done to maintain configuration during loss of primary power? What can be done to secure a design against illegal reverse engineering?

Xilinx FPGAs can be configured in a common daisy chain structure, where the lead device generates CCLK pulses and feeds serial configuration information into the next downstream device, which in turn feeds data into the next downstream device, etc. There is no limit to the number of devices in a daisy chain, and XC3000™, XC4000™, Spartan™, and XC5200™-series devices can be mixed freely with only one constraint: the lead device must be a member of the highest order family used in the chain.

These guidelines describe the configuration process for all members of the XC3000™, XC4000™, XC5200™, and Spartan™ FPGA devices and their derivatives. The average user need not understand or remember all these details, but should refer to the debugging hints when problems occur.

XC4000/XC5200/Spartan FPGA devices contain boundary scan facilities that are compatible with IEEE Standard 1149.1. This application note describes those facilities in detail, and explains how boundary scan is incorporated into an FPGA design.