Forums

DDR2 @ 400 MHz and Xilinx Spartan-3A[N] kits

Started by Tommy Thorn August 15, 2007
Xilinx has three very similar kits:
- Spartan-3A Starter Kit,
- Spartan-3AN Starter Kit, and
- Spartan-3A DDR2 SDRAM Interface Development Kit.

Only the latter is promoted as supporting DDR2 @ 400 MHz, but the only
difference listed between it and the Spartan-3A Starter Kit is the 133
MHz Crystal Oscillator and the lack of a 16 character, 2-Line LCD
display.

Is there some special about that kit, or will they all run the memory
@ 400 MHz given the right oscillator?

Thanks,
Tommy

Tommy Thorn wrote:
> Xilinx has three very similar kits: > - Spartan-3A Starter Kit, > - Spartan-3AN Starter Kit, and > - Spartan-3A DDR2 SDRAM Interface Development Kit. > > Only the latter is promoted as supporting DDR2 @ 400 MHz, but the only > difference listed between it and the Spartan-3A Starter Kit is the 133 > MHz Crystal Oscillator and the lack of a 16 character, 2-Line LCD > display. > > Is there some special about that kit, or will they all run the memory > @ 400 MHz given the right oscillator? > > Thanks, > Tommy
No FPGA kits for low cost FPGA families will deliver 400 MHz DDR speeds. 400 Mbps/pin is more likely with most vendors supplying the 200 MHz DDR2 capability and a few up to 233 MHz. If you expect 800 Mbps/pin, you are mistaken. For support of 200 MHz DDR2 memories, it may be the other kits have troubles with routing that would support the needed timing. The "right" pins need to be selected for the highest speed support.
On Aug 15, 6:48 pm, John_H <newsgr...@johnhandwork.com> wrote:
> No FPGA kits for low cost FPGA families will deliver 400 MHz DDR speeds. > 400 Mbps/pin is more likely with most vendors supplying the 200 MHz > DDR2 capability and a few up to 233 MHz.
Thanks John. My bad, I should have written "DDR2 @ 400 MHz data rate", following the terminology of ug226. Anyway, I should had read ug334 as it answers my question. The answer is they can all do it (rev C of the Spartan-3A starter kit requires a rework though). Regards, Tommy
Hi Tommy,

All three of these kits you mention have the slower -4 speedgrade component 
on them and will run the MIG-generated DDR2 controller at 133 MHz, giving 
you DDR2-266 performance.

The recently announced support for DDR2-400 performance requires a faster -5 
speedgrade component, and this solution was tested on Spartan-3A Starter 
Kits which had been built with the faster components.  The demonstration 
design posted on the web will generally run in a slower -4 speedgrade 
component -- at room temperature and nominal supplies -- as a science 
experiment.  If you want robust operation, you absolutely need the faster 
component.

Eric

 -- and I believe all three of these kits have the oscillator.  I think a 
natural question is
"Tommy Thorn" <tommy.thorn@gmail.com> wrote in message 
news:1187226750.867256.134160@i13g2000prf.googlegroups.com...
> Xilinx has three very similar kits: > - Spartan-3A Starter Kit, > - Spartan-3AN Starter Kit, and > - Spartan-3A DDR2 SDRAM Interface Development Kit. > > Only the latter is promoted as supporting DDR2 @ 400 MHz, but the only > difference listed between it and the Spartan-3A Starter Kit is the 133 > MHz Crystal Oscillator and the lack of a 16 character, 2-Line LCD > display. > > Is there some special about that kit, or will they all run the memory > @ 400 MHz given the right oscillator? > > Thanks, > Tommy >
Ah, I know it's bad form to reply to my own post, but I noticed some 
straggling text at the end of my response, which is a note I forgot to 
complete...

I believe all three of the kits actually have the 133 MHz oscillator.  I 
think a natural question is why this isn't on the product descriptions.  It 
has been the case on all of the Revision D kits I've material transferred to 
myself (now several dozen...)  I've contacted the owner of the product 
descriptions and asked him to review your comments and correct any 
discrepancies.  Given the content of my first post regarding DDR2 
performance levels, if knowing the exact differences in the kits is going to 
affect your purchasing decision, please email me directly and I'll find 
someone with the answer for you.

Thanks,
Eric

"Eric Crabill" <eric.crabill@xilinx.com> wrote in message 
news:fa0mc8$g2q2@cnn.xilinx.com...
> Hi Tommy, > > All three of these kits you mention have the slower -4 speedgrade > component on them and will run the MIG-generated DDR2 controller at 133 > MHz, giving you DDR2-266 performance. > > The recently announced support for DDR2-400 performance requires a > faster -5 speedgrade component, and this solution was tested on Spartan-3A > Starter Kits which had been built with the faster components. The > demonstration design posted on the web will generally run in a slower -4 > speedgrade component -- at room temperature and nominal supplies -- as a > science experiment. If you want robust operation, you absolutely need the > faster component. > > Eric > > -- and I believe all three of these kits have the oscillator. I think a > natural question is > "Tommy Thorn" <tommy.thorn@gmail.com> wrote in message > news:1187226750.867256.134160@i13g2000prf.googlegroups.com... >> Xilinx has three very similar kits: >> - Spartan-3A Starter Kit, >> - Spartan-3AN Starter Kit, and >> - Spartan-3A DDR2 SDRAM Interface Development Kit. >> >> Only the latter is promoted as supporting DDR2 @ 400 MHz, but the only >> difference listed between it and the Spartan-3A Starter Kit is the 133 >> MHz Crystal Oscillator and the lack of a 16 character, 2-Line LCD >> display. >> >> Is there some special about that kit, or will they all run the memory >> @ 400 MHz given the right oscillator? >> >> Thanks, >> Tommy >> > >
On 16 Aug., 07:27, "Eric Crabill" <eric.crab...@xilinx.com> wrote:
> Ah, I know it's bad form to reply to my own post, but I noticed some > straggling text at the end of my response, which is a note I forgot to > complete... > > I believe all three of the kits actually have the 133 MHz oscillator. I > think a natural question is why this isn't on the product descriptions. It > has been the case on all of the Revision D kits I've material transferred to > myself (now several dozen...) I've contacted the owner of the product > descriptions and asked him to review your comments and correct any > discrepancies. Given the content of my first post regarding DDR2 > performance levels, if knowing the exact differences in the kits is going to > affect your purchasing decision, please email me directly and I'll find > someone with the answer for you. > > Thanks, > Eric > > "Eric Crabill" <eric.crab...@xilinx.com> wrote in message > > news:fa0mc8$g2q2@cnn.xilinx.com... >
Xlinx S3A starterkit (and I belive S3-AN) kit have 50MHz oscillator and to my knowledge DDR2 solution will NOT work at 200MHz bus rate Xilinx tools have BIG TROUBLE meeting timings at 133Mhz already I have hard times beliving that the same design woud work at 200MHz as science experiment (at room temperature) Antti
Eric Crabill wrote:
> All three of these kits you mention have the slower -4 speedgrade component > on them and will run the MIG-generated DDR2 controller at 133 MHz, giving > you DDR2-266 performance. > > The recently announced support for DDR2-400 performance requires a faster -5 > speedgrade component, and this solution was tested on Spartan-3A Starter > Kits which had been built with the faster components.
Does the Spartan-3A DDR2 SDRAM Interface Development Kit have the -5 speed grade FPGA?
Hi Eric,

No, it does not -- it has a -4 speed grade FPGA like the other two similar 
kits.

Eric

"Eric Smith" <eric@brouhaha.com> wrote in message 
news:m3wsvvgfji.fsf@donnybrook.brouhaha.com...
> Eric Crabill wrote: >> All three of these kits you mention have the slower -4 speedgrade >> component >> on them and will run the MIG-generated DDR2 controller at 133 MHz, giving >> you DDR2-266 performance. >> >> The recently announced support for DDR2-400 performance requires a >> faster -5 >> speedgrade component, and this solution was tested on Spartan-3A Starter >> Kits which had been built with the faster components. > > Does the Spartan-3A DDR2 SDRAM Interface Development Kit have the -5 speed > grade FPGA?