Re: SimmStick FPGA module

From: Antti Lukats (antti_at_openchip.org)
Date: 02/08/05 

Date: Tue, 8 Feb 2005 11:04:04 +0100

Hi Martin,

Nice to see that some of my project are still live - I am the "inventor" of
the "SimmStick(tm)" standard :)

Please see my SHORT first comments below..

>"Martin Schoeberl" <martin.schoeberl@chello.at> schrieb im Newsbeitrag
news:sO%Nd.34738$2e4.30046@news.chello.at...
> Hi all,
>
> I'm thinking about a new board for JOP (or MB, NIOS). The board should be
small and
> cheap (below the S3 Starter Kit). It should only contain the absolute
necessary parts for a
> CPU design. Here is the suggested part list:
>
> FPGA: Cyclone EP1C3 or Spartan XC3S200
> 256Kx16 15ns SRAM
-- here I would like to argue a lot!
I understand that JOP runs ok in that memory, but... all the rest (if using
XC3S200) is uCLinux ready, except memory is not enough, so I would use 1
16bit SDRAM chip, not SRAM
XC3S200 is large enough to hold ucLinux ready MicroBlaze setup.
> 2 MBit serial Flash
-- again the 2MBit is enough for config, not for OS image, so if there would
be some means of having more, that would be nice, sure thats an price issue
> 3.3V linear regulation
> switching regulator for the core voltage
for a small FPGA linear regulator is ok, too cheaper sure burns more energy,
Trenz S3-1000 module as example has small linear regulator supplying max
0.9A for core
> 20MHz clock to the PLL input
NEEDED 5V compliance quickswitches !!!
all new FPGAs are not 5V tolerant and for both mech standards simmstick and
stamp 5V compliance is highly recommended to have, its a pain for
manufacturer but a big + for the user
>
> I've not yet decided about a X or A device.

hard decision hugh?
answer is simple. BOTH
it doesnt cost so much more todo both variants, you may supply more support
for either A or X as of your preferences (or customer interest) but from the
hardware build expenses its even cheaper (per board) to order a combined pcb
patch

> A remaining question is about the form factor. I still think it makes
sense to build
> the board as a module that can be integrated in a board with the
peripherals (similar
> to the ACEX and Cyclone modules I've done). There are two 'standards'
available:
>
> 1.) SimmStick, where the boards are designed as the 'old' PC SIMMs (see
[1]).
>
> 2.) The 'Basic Stamp' design is a board in the form of an old 40-pin (or
less) DIL IC.
> An example (from a Java processor competitor): [2]

You mean Parallax or those other guys? There are actually several stamp like
clones thing.
the stamp form factor is more challenging as the pcb are is very constrained
:(

> For a Java solution in an FPGA this board should beat the Systronix aJ100
Java processor
> modules (JStamp or JStick [3] - they have both form factors) in
performance and price.
> One nice thing about the SimmStick is that there are plenty of I/O boards
already available
> (see [4, 5, 6]).
> It seems a relative 'old' design, but it's a bus and I can build my first
JOP cluster with those
> boards ;-)

hm if you make the simmstick form factor board, here is a deal - I will
donate all my leftover simmStick stuff that includes some connectors and
protoboards etc, you can use all those boards and stuff as promotional bonus
give away for the early customers :)

> What do you guys think about this idea? Does it make sense to build a
another FPGA board?

hm.. I just recently looked at the parallax pricing.. still selling basic
interpreter for $49 (or more!) and still doing business. highend stamp are
in $99 range! So a fpga plugin module in $99 range, sure it might be
business idea still

>
> [1] http://www.simmstick.com/
> [2] http://jstamp.systronix.com/jstamp_photos.htm
> [3] http://www.jstik.com/
> [4] http://www.dontronics.com/dt.html
> [5] http://www.hobbyengineering.com/SectionSS.html
> [6] http://www.simmstick.com/simmstic1.htm
>
> Martin
> ----------------------------------------------
> JOP - a Java Processor core for FPGAs:
> http://www.jopdesign.com/
>
>

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