Hi all,
I want to know whether it is possible to program Spartan 3a for a run time partial reconfiguration. If yes are there any detailed demo programs available?
Regards, Parunoy
Hi all,
I want to know whether it is possible to program Spartan 3a for a run time partial reconfiguration. If yes are there any detailed demo programs available?
Regards, Parunoy
Parunoy,
What you describe is not supported in Spartan 3A.
Austin
I did think s3a ICAP has access to FPGA configuration ? I know there are no demos available, but to say that S3a is totally incapable of runtime reconfig? or I have i missed something? the lack of tools, demos and documentation doesnt always mean that the feature itself is missing, only that is harder to use.
Antti
kill the glitch-bitch!
ok, things there are things potentially doabl (but not recommended) and things really doable and working ,
Antti
Antti,
Yes. For example, if you stopped the system clock, reconfigured, and started the clock again, that would probably work just fine.
It was decided (long ago) that some features were more important to some customers, and since Spartan parts are concerned with: cost, cost, cost (in order of importance), things like reconfigurability are reserved for the Virtex line (where we are not so greatly constrained).
Austin
Hi.
Thanks for replying so soon. Is there a detailed explanation for the demo (OUT-OF-BOX) as I think that demo program uses the reconfigurability of s3a by accessing the on board PROMs? The demo uses a Picoblaze controller to select the confign from the specific PROM. Does the FPGA reset everytime it is configured from the PROM?
Parunoy
Hi again,
Actually what i currently want to do is:
Regards, Parunoy.
yes, the FPGA will go FULL reset and re-configuration cycle during triggered multi-boot
Antti
Austin,
Just for clarification - for all S3 devices partial reconfiguration is either: A) guaranteed to work by stopping clocks, so to avoid glitches or B) not supported at all, so everyone just forget it
Scenario "A" leaves for external reconfiguration, but rules out internal one.
Have you considered using both an up counter and a down counter and functionally selecting between the two of them?
I just reported on 3A,
I would have to go ask about 3, 3E.
Austin
no need go asking.
S3A is first ever Spartan with ICAP.
ditto.
whatever the supported features of Spartan3A-ICAP are, no other spartan family has anything related to self-reconfig at all, there is no ICAP.
Antti
page 248:
Tells you exactly what is supported by ICAP (and the list does not include partial reconfiguration).
If you want to reconfigure to a new, or different bitstream, ICAP may be used to do that.
Austin
well, page 248 says "same as slave-map"... via slavemap writing bitstream on frame-by-frame basis should be possible. if the same is possible via ICAP, i would say it is partial reconfiguration ??
maybe there are reasons why it would not work properly or have side issues glitches?
but it should be possible to reconfigure some cells in S3a in runtime using ICAP?
Antti
Here is a radically different idea: Why (partial) reconfiguration? Anything you can do with reconfiguration, you can also achieve by logic duplication. Reconfiguration is just more efficient and might give higher performance. The OP seems to aim for small changes, like changing up-count to down- count. For that, reconfiguration is gross overkill. I suggest looking at the traditional solution to such designs, namely logic duplication. An up/down counter is hardly bigger than an up-counter... Peter Alfke, Xilinx Applications
sure, the OP was maybe barking under wrong tree.
the topic itself is still interesting, if I have some soft-core say in right half of the die and if i want to change the PULLUP to PULLDOWN on the left side of the die
I would assume this could be done by S3A ICAP ???
most MCU's can have pullup control in software, FPGA's have that control only via configuration, I could see S3A adds at least partially this possibilty or is there some thing that prevents such runtime reconfig?
Antti
Possible,
Yes.
Supported,
No.
'Play' all you like, but it is unsupported.
If it does something useful for you, great. But, as an unsupported feature, we have no obligation to provide it (it might go away, doubtful, but a possibility if we change something to fix something else, if something needs fixing -- or if we cost reduce something to reduce costs).
The pdf lists the supported features. Reprogramming live is noticeably absent.
Austin
Antti, in partial reconfiguration (as in many things) the devil is in the details. Partial reconfiguration can inherently change only one frame at a time. In Virtex, the change is guaranteed to be glitchless (no erroneous codes), but in Spartan there will be glitches =3D erroneous codes. If you stop the clock, these glitches will probably (?) not cause any harm...
If Xilinx were to support such a feature in Spartan, there would be so many "ifs and buts" that we would would perhaps make some designers happy, but definitely alienate others. So we decided not to support this feature in Spartan. Use Virtex if you need partial reconfiguration... Peter
LOL, i may wanna want to support features available in Xilinx silicon that useable in some given application. If I have such application I may also do some reconfig in S3A, not matter it is officially supported.
But agreed, what is not officially supported is no on the recommended list of things to be done. right.
Antti to Peter, I have an application where even glitchy reconfig could be VERY useable in S3, the project is on ice right now, but i may get it active some day
interface:
LOL, yes I have seen that paper too of course. I forgot and did write incomplete I should have said no other spartan has self-reconfiguration WITHOUT special externak wiring, i.e. using on chip resources onlye (ICAP)
Antti
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