-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 (I'm assuming it was an accident your last reply didn't go to the list, so forgive me if it was meant to be a private reply!)
howard parkin wrote: > For analogue and Dual link DVI, freq is the pixel clock. > For Single link DVI, freq needs to be 2 x the pixel clock rate. OK. Out of curiosity, how come analogue and single-link DVI aren't the same, and dual-link DVI a different case (since analog and single-link DVI have pretty much the same max pixel clock) Perhaps this is just a facet of how the external video encoders take their data; single/double wide/edge etc.? >> Is this scheme based on the DCM configurations mentioned here: >> >> http://www.xilinx.com/products/boards/s3estarter/files/s3esk_frequency_generator.pdf >> >> http://www.xilinx.com/products/boards/s3estarter/files/s3esk_frequency_generator.zip > > This is where I first heard of the DCM tweeks, but we are not using > the frequency synthesis scheme described in these papers. In the > Xilinx scheme, there was significant jitter in the input clock because > they used a non-integer division of the source clock, and hence the > period between +ve edges of the DCM input clock varied ie jitter. > We always divide our source clock by an integer, so that the > period between successive clock cycles is always the same, ie > no jitter. Is the clock generator RTL available anywhere - will it be part of the GPL part of the RTL? I'm curious mainly because I've been playing around with VGA output from a Spartan3 starter kit module, and so far, I've pretty much been limited to [EMAIL PROTECTED], due to generating the pixel clock using a simple DCM configuration driven by the 50MHz crystal. Having this kind of flexibility would be great! -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGawy5hk3bo0lNTrURAn/jAJ0SLisjCdK2SGLdpBAHf5a3XMzLhQCg4yK+ XOWxOaXyOVmnt4EpvUOl0oM= =lE6j -----END PGP SIGNATURE----- _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
