LVDS for lcd panel and RocketIO

Hi,

I want to connect a LCD Panel with LVDS to my Virtex2Pro. The LVDS 
frequency is max 80 MHz. My fpga runs at 100 MHz and is speed grade -5. 
Do I have to get into the RocketIO stuff now, or does it have nothing to 
do with it?

regards,
Benjamin

On Sun, 10 Apr 2005 22:21:07 +0200, Benjamin Menk�c wrote:

> Hi,
> 
> I want to connect a LCD Panel with LVDS to my Virtex2Pro. The LVDS 
> frequency is max 80 MHz. My fpga runs at 100 MHz and is speed grade -5. 
> Do I have to get into the RocketIO stuff now, or does it have nothing to 
> do with it?
> 
> regards,
> Benjamin

Nothing to do with it. RocketIO is for serial protocols like InfiniBand,
Fibrechannel or PCI Express. The data rates on those is multiple
gigabits/second not a puny 80MHz. You can easily run LVDS at 80MHz, I've
run it at 266MHz across ribbon cables using a Spartan3 which is slower
than a V2P.

> I want to connect a LCD Panel with LVDS to my Virtex2Pro. The LVDS 
> frequency is max 80 MHz. My fpga runs at 100 MHz and is speed grade -5. Do 
> I have to get into the RocketIO stuff now, or does it have nothing to do 
> with it?

LVDS Panels use a multiplexing scheme, whereby the LVDS link runs at a 
multiple (eg 7 x) of the incoming clock. So, if what you are trying to build 
is an equivalent to the usual LVDS TX chip (90C383 or similar) then you will 
need to generate LVDS signals at (max) 80 MHz times 7, ie 560 Mb/sec

I don't know enough about V2Pro to know how you would do this.

Dave




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Hi,

yes a LVDS clock of 500 MHz would be possible. I have read some appnotes 
and I guess that I need an external oscillator for that frequency. 
However I am not sure yet howto generate the fraction of 500 MHz, for 
the parallel data, 71,42 MHz. I think 500 MHz is to high as input for a 
DCM.... Thats my question about appnote xapp622 that I have posted in a 
different topic.

Do I still don't need to do anything with rocketIO at 500 MHz?

regards,
Benjamin

"Benjamin Menk&#4294967295;c" <benjamin@menkuec.de> schrieb im Newsbeitrag
news:d3dh00$dli$00$1@news.t-online.com...
> Hi,
>
> yes a LVDS clock of 500 MHz would be possible. I have read some appnotes
> and I guess that I need an external oscillator for that frequency.
> However I am not sure yet howto generate the fraction of 500 MHz, for
> the parallel data, 71,42 MHz. I think 500 MHz is to high as input for a
> DCM.... Thats my question about appnote xapp622 that I have posted in a
> different topic.
>
> Do I still don't need to do anything with rocketIO at 500 MHz?
>
> regards,
> Benjamin

YES positive nothign todo with RocketIO

there is no 560MHz clock involved ore needed, you can achive 560MBit/s data
rate using normal LVDS and DCM the DCM output frequency is 280MHz, that
gives you 560Mbit data rate as you use DDR io what effective doubles the
datarate.

read the xilinx appnote there is an example of this

antti