Hi all, I am actually trying to switch a virtex2 project to spartan3. While implementing the design I got several timing errors. One reason is that the timing parameter "CLK to valid Data on Pad" (Tiockon). The data sheet of virtex2 gives a value of 3.51ns. The value for spartan3 is 5.865ns - which is much higher!!! . I got this value for spartan3 from Timing Analyzer (Vers. 6.1.03i). In the newest datasheet of the spartan3 the chapter "switching characteristics" is still quite empty. So I really wonder what the XILINX guys do. Selling a chip without timing specs? Is the spartan3 really much slower than the Virtex2? Any comments? Any Spartan3 Users?
The Spartan-3 speeds files were recently updated to better reflect actual silicon measurements. The previous speeds files, v1.27, were considered PREVIEW level and were based primarily on simulation data. The recent speeds files, v1.29, have now graduated to ADVANCE level, indicating that the data is based on actual device characterization data measured on Spartan-3 devices.
The particular parameter that you mentioned, Tiockon, ranged from 1.099 ns to 6.197 ns using the -4, v1.27 speeds file. The value reported by the timing analyzer, 5.865 ns, is specific for the way that your application was implemented in the FPGA.
The Tiockon parameter now ranges from 1.127 to 4.000 ns using the -4, v1.29 speeds file. Re-running the design using the speeds files will improve the performance. Similarly, setting some timing constraints on the particular path may improve the results further still.
Optionally, the v1.29 speeds files now also include a -5 speed grade, which is about 13% to 15% faster than the new revision of the -4 speed grade.
Now for the next logical question: Where can I obtain the new speeds file?
Please point your browser to the following web link.
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Then please download and extract the referenced ZIP file. Then, please re-run the Xilinx implementation software to take advantage of the extra performance.
--------------------------------- Steven K. Knapp Applications Manager, Xilinx Inc. General Products Division Spartan-3/II/IIE FPGAs
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--------------------------------- Spartan-3: Make it Your ASIC
Hi Steve, I have a question about spartan 3. We are xilinx customers and have ordered spartan 3 device long back. Also we have ordered engineering samples. But the distributor can't answer when the order comes to us. Can you please tell me whether spartan 3 1.5m devices are being shipped(engineering samples)? Anjan
"Anjan" skrev i melding news: snipped-for-privacy@posting.google.com...
We have the same problem here.. Prototyping boards are ready and we have been promised devices for a quite long time. I hear xilinx has problems in production, wich is boring for us having quite a few boards ready :/ We were also promised a few samples with 2.5v max io, but they showed up either. From now on , we will be VERY careful to go for future devices. However, I hope they will appear in the near future.
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