Answers Database Virtex Configuration: Issues on configuring Virtex and 4000X devices in daisy chain Record #5381 Product Family: Hardware Product Line: Virtex Product Part: Virtex General Hardware Problem Title: Virtex Configuration: Issues on configuring Virtex and 4000X devices in daisy chain Problem Description: Urgency: standard Problem description: Issues to be aware of when configuring virtex and xc4000X devices in daisy chain Solution 1: Virtex and XC4000X devices may be mixed in a serial daisy chain, with the following conditions.     Required     --------     1. All DONE pins are wired together with an external pullup        to 3.3V     2. XC4000X devices must have the bitstreams generated        with the following options SyncToDone = Yes OutputsActive = DI, DI_PLUS_1, or DI_PLUS_2 GSRInactive = DI, DI_PLUS_1, or DI_PLUS_2     3. If programming by a micro-device, at least 3 clocks must        be issued after DONE has gone high or the devices must        use a USER clock for the startup sequence. There is no ordering requirements for the daisy chain. For ease of design, families should be grouped togethert, this will also reduce the bitstream size. Solution 2: The following devices are permitted in the serial chain:    XC4000EX    XC4000XL    XC4000XLA    XC4000XV    SPARTANXL All other devices are NOT permitted in the serial chain including:    XC3000*    XC3100*    XC4000    XC4000E    SPARTAN    XC5200 End of Record #5381 - Last Modified: 01/04/00 11:44

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