Hi,
Does anyone know the frequency of the internal oscillator of Xilinx VirtexE FPGAs which is used to generate the CCLK for Master-Serial configuration mode? I'm aware that the datasheet specifies 4 MHz as default CCLK frequency but that isn't necessarily identical to the frequency of the oscillator.
What's the behavior of this oscillator after configuration? Is it turned off or can it be disabled through some option in the bit file?
Regards
Stefan Tillich
From the datasheet:
The CCLK frequency is set using the ConfigRate option in the bitstream generation software. The maximum CCLK frequency that can be selected is 60 MHz. When selecting a CCLK frequency, ensure that the serial PROM and any daisy-chained FPGAs are fast enough to support the clock rate. On power-up, the CCLK frequency is approximately
2.5 MHz. This frequency is used until the ConfigRate bits have been loaded when the frequency changes to the selected ConfigRate. Unless a different frequency is specified in the design, the default ConfigRate is 4 MHz.It doesn't specify whether the internal oscillator stops running when config is complete, but the CCLK output certainly does. Since Virtex no longer allows user access to the internal CCLK oscillator I don't see why they would leave it running.
If they dont respond here, email Xilinx one of those addresses under "contact" link, then (additinally) open a 'Webcase" (under tech support" links) for which you need to be registered. Registration takes 24 hours but do NOT specify yourself as a student, make it professional engineer otherwise they refuse to talk (as happened to me and I had to get answers from here... thanks to all you people).
Finally call their tech support hotline, again need to be registered on their Web... Maybe Peter Ryser can answer you - look for him under "Question on Xilinx VirtexProII" I posted on this group, hi sresponse was MOST COMPLETE, so you may want to ask him YOUR question. My posting was dated by October 15 here.
do NOT email Peter Ryser, ask on this Newsgroup instead. He is already overloaded, if gets any mor eemails he won't respond ever and reduce ability to respond even to Newsgroup, so... ask on this Newsgroup and not email.
Madman
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.