Non-volatile FPGA in a small package

On Nov 11, 8:04 am, Thomas Stanka <usenet_nospam_va...@stanka-web.de>
wrote:

> You can't use clk input buffer on non clock input pads, but you can
> use any input as feed for the internal clock buffer (GLint) to drive
> the clocks from any input you like. The perfomance may be much better,
> when using the clock pads, but you are not limited.

Maybe if you tell it exactly what primitives you want you can do it.

But the obvious case of simply writing HDL code that uses a non-clock
input as a clock, fails.  Wheras it works on X or A - albeit with
warnings.

Hi,

On Nov 8, 8:43 am, "John_H" <newsgr...@johnhandwork.com> wrote:
> "Kryvor" <kris.vorw...@gmail.com> wrote in message
>
> > (It looks as thoughActelcarries some smaller ProASICPlus parts in a
> > TQFP 100 package.  Those parts have 2 PLLs and are Flash-based
> > [reprogrammable, immune to SEUs, etc.].)
>
> The Flash cells may be imune to SEUs but the active logic certainly isn't.
> SEUs "tend" to be noticed in SRAM cells first but registers are also
> affected by the same radiation for FPGAs of any flavor as well as ASICs and
> other standard parts.

Fair enough.

It would have been more accurate for me to say that Actel's Flash
FPGAs are immune to configuration loss due to single-event errors.

In the interest of thoroughness, Actel's Flash FPGAs *have* undergone
substantial FIT testing and are quite resilient (compared to SRAM
devices) in terms of their alpha and neutron radiation handling:
http://www.actel.com/products/solutions/ser/


cheers,
K.

Hi,

I apologize if this gets double-posted; I think that Google Groups may
have eaten my first reply.  (So this is attempt #2 :)


> > You might find that Actel suits your needs ...
>
> >http://www.actel.com/documents/selguide.pdf
>
> > (It looks as though Actel carries some smaller ProASICPlus parts in a
> > TQFP 100 package.  Those parts have 2 PLLs and are Flash-based
> > [reprogrammable, immune to SEUs, etc.].)
>
> Yes, however there's a big differnece between developing for these vs.
> Altera or Xilinx SRAM parts: the toolchain is less integrated and thus
> much slower,


I'm not entirely sure what you mean by "less integrated" -- Actel's
toolflow is completely integrated inside the Libero GUI, and is also
completely automatable/scriptable from the command line, using TCL
scripts.  (While the toolflow *does* use Synplify for RTL synthesis,
this is often viewed as a strong point due to the high quality of
results achievable using Synplicity's software.)

Work is being done all the time to improve the runtime and performance
of the designs produced by the toolsuite; if you have a strangely-slow
case, I would urge you to bring this to Actel's attention so that
engineering can take a look at it.



> and the programmer is outrageously slow and pricey for
> what you get.  If you are used to fully integrated toolflow, and to

I believe that the FlashPro programmer comes with most of the Starter
Kits, which I've always found were pretty well-priced.  (I think that
you can also purchase the standalone programmer separately, but to be
honest, I don't recall its price or how it compares to other
companies.)

That said, if you've encountered any strange, slow-programming cases,
you should bring it to Actel's attention.


> It also seems that you can't get pullups on inputs, and instead of

Not true :)  I/Os in Proasic/Fusion/Igloo can be configured for
numerous different I/O standards and have various features, including
low power mode, internal pull-up resistors, Schmitt trigger for
inputs, and selectable drive strength and slew rate.


> merely being cautioned against using non-clock inputs as clocks, you
> literally can't do it - meaning board designs with stupid mistakes

Not true :)  In general, non-clock I/Os in Proasic/Fusion/Igloo can
drive internal clock buffers from basically any input.  (There are
some minor caveats where only certain I/Os can be used when employing
specialized features, like quadrant clocks and certain PLL
configurations and/or I/O bank configurations.)


> On the other hand, if you prefer to do everything in simulation and
> not make incremental trials in hardware, and you value synopsis over X

Incremental trials in hardware are certainly encouraged :)  Actel's
Flash products are reprogrammable, and in practice, the toolflow is
heavily optimized for high-quality, fast runtime.  Again, if you've
encountered an oddly slow case, it can't hurt to bring it to Actel's
attention so that the problems can be looked and rectified.

(Also, a minor point of note -- I don't know if Synopsis' tools work
with Libero.  I know that Synplicity's Synplify ships with all
versions of Libero, and some versions are also compatible with Magma's
Palace software.)


cheers,
K.