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 2 MBit serial Flash 3.3V linear regulation switching regulator for the core voltage 20MHz clock to the PLL input
I've not yet decided about a X or A device.
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]
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 ;-)
What do you guys think about this idea? Does it make sense to build a another FPGA board?
[1]
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Martin
---------------------------------------------- JOP - a Java Processor core for FPGAs:
-- 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.
-- 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
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
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
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
sense to build
peripherals (similar
available:
[1]).
less) DIL IC.
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 :(
Java processor
performance and price.
already available
JOP cluster with those
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 :)
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 $99 range, sure it might be business idea still
Sorry, I should have given the credits to you! BTW.: Is this format still alive?
However, SRAM is way much simpler to handle. I think SDRAM is a pain.
Could be an option. However, handling options are a pain in the manufacturing.
The 3.3V linear regulation is only for the IO. The core voltage gets a switching regulator. If you are using this module in a 3.3V SimmStick bus you can go without the linear regulation on board (will be a sloder jumper)
That's again pain. I was thinking about being not 5V compliant. It's time to stop these 5V designs! Or, add series resistors - bad for the bandwidth.
I don't think it's possible to build one pcb for both. I want the module to be small. As small as the 9 part SIMMs (79mm x 21mm).
Yes, I would need parts on both sides of the pcb. However, it's only a little bit more expensive in the manufacturing.
That's a deal :-) However, it's an indication that you don't buy ino the bus anymore.
"Martin Schoeberl" schrieb im Newsbeitrag news:H41Od.35105$ snipped-for-privacy@news.chello.at...
of
no problem. hm alive I think yes, I a havent be doing much (read anything) for years but there are still products around
using
yes no, once the SDRAM controller is once configured it works, but agree from the ip core side its more painful, still 4MByte of onboard RAM would just GREAT!
hm I think it is possible to make a layout for either 54TSOP sdram and SRAM (that would be beneath it) please consider.. that would be a mount option, :( but well I would consider. I have several FGPA boards with 0.5MB RAM, and all of those are "bad" as they can not boot linux :( hm I have 40 PCS of those SDRAM overleft in cut tape, again if there is place to solder them those are yours for the project...
would
issue
manufacturing. yes I, know the manufacturing options are pain, its a mistake I have done and learned as well, I wanted the first simmstick so be cheap and flexible by providing lots of mounting options, that was bad actually would have been better to add it all and sell a bit higher
energy,
switching
hm ok, besides for spartan at least 2.5V is also needed !! even if 2.5 ios are not used that an additional small regulator :(
and
to stop
yes pain, would be so much easier to go only by 3.3 or 2.5
support
the
pcb
to be small.
yes that should be the small board, I meant to produce two different boards!! (not one that can be used with both FPGAs) each time you order PCB so you always get both X and A, if there comes big overleft of X or A boards you can etiher sell away the remaining plain PCB or then order the best seller as separate PCB
(or
like
constrained
little bit
depends how much you squeeze and what production quantities are.
The original STAMP in DIP28 where partially hand made, the Parallax people had a barbeque at behind the office and a tin-pot in the middle so they had a party and at the same time soldered those DIP pins to the stamp modules - that also in large numbers. I think they dont have those BBQ anymore but for the long time this was the procedure. ah old good days ;)
boards
first
bonus
bus anymore.
not necessarily - I have been occupied.
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some older pictures of family (part of it) there are now 3 kids. Anna youngest is 1y3months. sick right now :(
basic
are
Good luck, and I see what support I can give on the way, there are some ideas for SimmStick that I did not realize, maybe its time for them to become true.
the cheapest mm with XC3S200 is 114.84EUR add 5 EUR for the special connectors, then you would need to always make a custom PCB with those 0.8mm headers that adds up price. A simmstick can be plugged into solderless breadboard or any 0.1 proto board and requires no special connectors, so its a little bit of different in the use. If the fgpa-simmstick is sub 99USD then, well there is room for everybody on this planet. :)
the micromodules are nice too of course ! Antti PS I am little disappointed in the designer of the RetroBB for the trenz micomodules, the delta sigma AD DA circuitry, there are some very important caps and resistors missing... for sound applicaiton the input should be AC coupled and comparator biased with vcc/2 and the output again should be AC decoupled (well thats not so big mistake, but still it isnt nice to feed 2V DC into headphones..) I think the circuitry is 1:1 copied from Xilinx appnote without thinking. Sometimes thinking is good, even I consider that as heavy physcial work (to be minized if possible). Sorry - I was really terrified when I looked at the retroBB schematics!
What is the use of the finger connector on Micromodule
Larry
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Yes, I will go with the SDRAM. Do you have an idea what chips are used these days. I've found Micron MT48LC4M16A2 could be a choice.
switching
Nice, but still many external components. However, as it looks like that I will use the Cyclone I only need one switched power supply (1.5V).
Why? You can use the internal PLL. And I'm not using an XTAL, but an integrated osci. If you really need a different frequency than you can change the osci yourself.
could be nice Do you mean LVDS standard with the termination resistor network?
He he. You do not need a real motherboard. Just single row connectors on a breadboard and go (or the expensive version of this that I provide: Simpexp)
Yes, looks good to me. If you still have spare IO, routing the address lines for the superior model might be interesting. Maybe there is no more line to route actually, I didn't check
May I ask why ?
The EP1C3 has 2910 L.E., 1 PLL and 60kbits of ram. The XC3S200 has 4320 L.C., 4 DCM/DLL, 216kbits of ram and 12 dedicated multipliers
(Note that it's _not_ a A vs X issue ! Theses chips are just not of the same generation ...)
integrated osci.
First yes sorry I always write XTAL while I mean a complete osc ... ;) Why : It's not big and when you have a specific frequency for a screen / uart / ... generating it with the PLL is sometimes annoying ...
could be nice
Yes, that what I meant. Don't put the resitors by default, just route them as if they were differential.
I personally thought that the simmstick standard has way too few pins (30) for any serious work. That was the main reason for me to 'invent :-)' my own bus standard. The latest incarnation is called 'H-Storm' and can be found here:
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I would suggest you to take a look. It has more pins (72) and thus much more versatile than the simmstick. It's already 3.3V powered so you can save the regulator. Even better: it has pins for 2.5 and 1.8V power as well, so you might not need to deal with power at all (not with the SpartanIII, the core power there is 1.2V).
I'm in the process of building an FPGA board to that bus myself, using a spartan II-e device, but it shure would be nice to see someone else building something along those lines.
Hi Martin, I would not support the design of your product based on the simmstick for the following reasons:
(1) The signaling standards supported by the simmstick are very limited and I doubt very much whether you could support any of the newer, low voltage , high speed, differential signaling standards.
(2) It is very difficult for hobbyists to create their own simm sticks to run in parallel to your proposed design as most Internet based prototyping companies will not support the thickness of the pcb required( this was the case, as far as I know, from my inquires last year).
(3) As mentioned previously and discussed in other Internet based discussions the limited number of GPIOs pins that will be available to the user is an extreme disadvantage.
It seems to me that your best bet is to use a SODIMM socket compatible design, but this will be only reinventing the wheel.
It's almost the same pinout for up to 64MByte (only one additional address line).
multipliers
A little correction: The Spartan-3 has 3,840 LC/Es (multiply the Slices by two and you get the LUT count).
Yes you're right, S3-200 is larger, has more memory (but less memory blocks 12 vs. 13) and multipliers. However, my main application for this board, JOP, can be clocked higher in the Cyclone than in the Spartan-3 (101MHz vs 83MHz, both fastest speed grades). The S3-200 is more expensive than the EP1C3. However, both are large enough for a CPU with some peripherals. That's the main application, in my opinion, for this board.
And another reason: There are many Xilinx boards (and also cheap one) available, but not so many for Cyclones. This board would be very similar to Koljas Micromodule.
integrated osci.
yourself.
/ ... generating
Yes, a good idea! I will add the spare pads on the back side of the pcb. That does not cost pcb place resources.
connector could be nice
if they were
You mean same lenghth, constant distance. However, there will be almost no routing from the FPGA to the connector. I'll expect only a few mm from pin to connector.
Martin
---------------------------------------------- JOP - a Java Processor core for FPGAs:
If you do decide to build a new proto board make sure you've got some form of securely mounting it. If you go with a SimmStick this is taken care of, but I had problems mounting your Cyclone JOP boards for prototyping. I didn't have time to design/build a motherboard to plug the modules into to get access to the connectors so had to build a complicated jig to hold them securely.
Nial.
------------------------------------------------------------- Nial Stewart Developments Ltd FPGA and High Speed Digital Design
Another idea: What do you guys think about adding a slot for a SD Card [1]. They are cheap (about EUR 10,- for 128MB) and you get them up to 1GB! However, the impact on the board is high: The connector is 'big' and increases the board hight. A FPGA with a higher pin-count is needed. For the solution without the SD Card a 100pin TQFP would fit, but now a 144pin is needed - again a larger board. And this adds again a few EUR/$. All these design decissions! You start with a minimal core design and than start adding (unnecesssary) features again.
BTW: Has somebody inplemented an SD Card interface in an FPGA. It should not be too hard [2]. The simplest solution would be the SPI bus.
[1]
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[2]
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Martin
---------------------------------------------- JOP - a Java Processor core for FPGAs:
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"Martin Schoeberl" schrieb im Newsbeitrag news:sO%Nd.34738$ snipped-for-privacy@news.chello.at...
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