Reconfigure Spartan 3 without losing BRAM?

Question

Hi folks-I was wondering if it is possible to reconfigure a Spartan 3 duringoperation without losing the BRAM contents or overwriting it.  Is thispossible with other FPGAs?  Column-wise reconfiguration, would work, Isuppose.   Jake

Symon · Accepted Answer

Hi Jake,I seem to recall you can read back the whole bitstream from Xilinx FPGAs. I think this includes the current bits in the BRAMs. If you knew which bits were which, you could extract the BRAM bits and plug them into the new bitstream you're downloading.Maybe.Cheers, Syms.

Steven K. Knapp · Answer

Spartan-3 FPGAs only support column-wise reconfiguration.  As long as youavoid reconfiguring the DCM/Block RAM columns, you should be okay.-- SKK

rickman · Answer

I have been meaning to send you an email to ask if the Spartan 3s aresupported for modular reconfiguration yet.  How is that going?  I seemto recall that there were a couple of things that had to be resolvedbefore the work could even begin.  One was a "bug" or some aspect of theISE software and the other was a work around for the fact that Spartan3s don't have any tristate buffers.  Have either of these issues beenworked?  How close are we to having a solution?  -- Rick "rickman" CollinsIgnore the reply address. To email me use the above address with the XYremoved.Arius - A Signal Processing Solutions CompanySpecializing in DSP and FPGA design      URL  King Ave                               301-682-7772 VoiceFrederick, MD 21701-3110                 301-682-7666 FAX

Steven K. Knapp · Answer

[snip]The modular support using bus macros is not supported currently.  It issupported via the "bitgen -r" approach, as described in the following AnswerRecord.Is partial reconfiguration supported on Spartan-3 devices?---------------------------------Steven K. KnappApplications Manager, Xilinx Inc.General Products DivisionSpartan-3/II/IIE FPGAs  Make it Your ASIC

rickman · Answer

Unfortunatly I was not trying to do "partial" reconfiguration, butrather "modular" reconfiguration which seems to not be supportedaccording to the answers record.  At the time we last discussed this, Ithought you had indicated that Xilinx was committed to supportingmodular reconfiguration in the Spartan 3 devices.  Is that no longer thecase?  -- Rick "rickman" CollinsIgnore the reply address. To email me use the above address with the XYremoved.Arius - A Signal Processing Solutions CompanySpecializing in DSP and FPGA design      URL  King Ave                               301-682-7772 VoiceFrederick, MD 21701-3110                 301-682-7666 FAX

Reconfigure Spartan 3 without losing BRAM?

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