Author Archives: Jan

Wednesday, December 18, 2002

Free Xilinx PicoBlaze Microcontroller Expands Support to Virtex-II Series FPGAs and CoolRunner-II CPLDs. PicoBlaze User Resources.

Earlier coverage.

Regarding PicoBlaze for CPLDs, e.g. CoolRunner-II, lacking any on-chip block RAM instruction memory, the PB for CR2 requires you provide an external 16-bit wide instruction RAM.  This may prove prove prohibitive in board area and cost.  You can reduce the requirement to 8-bit external memory using a few more macrocells, of course, but in my opinion this application is a better fit for a device with embedded block memory (e.g. Spartan-IIE, etc.).

This does illustrate the utility and value of a modest amount of embedded RAM and/or FLASH in these larger CPLDs — an idea whose time has come.

Monday, December 16, 2002

Xilinx: 90nm Process Technology Drives Down Costs.

IBM: IBM and Xilinx prepare for production of first 90nm chips on 300mm wafers.

UMC: UMC AND XILINX ON TRACK TO MANUFACTURE 90NM PROGRAMMABLE CHIPS ON 300MM WAFERS IN 2003.

Anthony Cataldo, EE Times: IBM, Xilinx tape out first 90-nm FPGAs.

Therese Poletti, San Jose Mercury News: IBM-Xilinx new chip moves to production.

John Blau, IDG News Service: IBM, UMC ready first 90-nanometer chips.

1.2V!

Tuesday, December 3, 2002

Xilinx:Tarari adopts Xilinx Technology for Reconfigurable Content Processor Solutions.

“Tarari content processors are hardware and software-based subsystem building blocks (silicon, boards, etc.) that snap into servers, appliances and network devices, allowing for the first time the inspection of application layer content at network speeds…”

Tarari.

Here, March: Applications of racks full of FPGA multiprocessors:

“I suppose my pet hand-wavy application for these concept chip-MPs is lexing and parsing XML and filtering that (and/or parse table construction for same). Let me set the stage for you. “”Imagine a future in which “web services” are ubiquitous — the internet has evolved into a true distributed operating system, a cloud offering services to several billion connected devices. Imagine that the current leading transport candidate for internet RPC, namely SOAP — (Simple Object Access Protocol, e.g. XML encoded RPC arguments and return values, on an HTTP transport, with interfaces described in WSDL (itself based upon XML Schema)) — imagine SOAP indeed becomes the standard internet RPC. That’s a ton of XML flying around. You will want your routers and firewalls, etc. of the future to filter, classify, route, etc. that XML at wire speed. That’s a ton of ASCII lexing, parsing, and filtering. It’s trivially parallelizable — every second a thousand or a million separate HTTP sessions flash past your ports — and therefore potentially a nice application for rack full of FPGAs, most FPGAs implementing a 100-way parsing and classification multiprocessor.”

Friday, November 29, 2002

Lauro Rizzatti, in EEdesign: Gates, lies and common sense. Rizzatti revisits the marketing gates issue.

“Realistically, now there is a simple, practical way to compare the design capacity of two emulation solutions based on the Virtex-II components. By listing type and quantity of Virtex-II devices allocated to mapping the design-under-test, possibly augmented by one or more external memory banks, you can now truthfully and reliably evaluate two or more emulation systems.”

Well that’s not very helpful. Far better is to simply describe a capability vector of total resources. Then you can compare across families and across vendors.

The vector should include (#LUTs, tILO, amt. of each layer of memory hierarchy, external RAM). Thus a system with two XC2V6000-5’s might be

(68 KLUT, 410 ps, 1056 Kb LUT RAM, 2.6 Mb BRAM, ?) * 2 => (135 KLUT, 410 ps, 2 Mb LUT RAM, 5.2 Mb BRAM, ?)

and a system with four EP1S60s might be something like

(57 KLUT, ? ps, 574 M512s, 292 M4096, 6 MegaRAM, ?) * 4 => (228 KLUT, ? ps, 1.1 Mb M512s, 4.6 Mb M4096s, 13.5 Mb MegaRAM, ?).

If your problem domain warrants it, by all means, grow the capability vector to include multiplier resources, embedded processors, high speed serial resources, etc.

Congratulations to Altera for simply naming their new parts with the most imortant element of this capability vector, KLUTs.

See also these two articles.

Thursday, November 28, 2002

Ch-ch-ch-changes
I have returned full time to the software world; without discussing specifics, my aim is to significantly improve the lives of software developers and software users alike.

Fear not, I anticipate that this site will continue to report upon news, and muse aloud about ideas, in the FPGA CPU and SoC space. However, expect the reports to be more sporadic, and any musings to be less elaborate.

Thanks giving
To my wonderful family, thank you. How happy I am that we are here together to share life’s rich pageant.

Thanks to my friends. I am so fortunate to share friendship with some most excellent kindred spirits who are so generous with their time, regard, insights, kindness, well wishes, and good cheer. Special thanks to those several of you whom I am privileged to count as close friends. Thank you for being one in a thousand.

I thank and remember those who have gone before, who lived and worked and fought and died to make the world a happier place for this ungrateful entitlement generation. Many of us here in the western world have never known want, disease, hunger, strife, nor war in our backyard. Let us remember those that still live with these hardships.

Apropos of this site, I also thank the vast legions of hard working engineers and scientists, and their collected and focused embodiments in corporations, for ceaselessly advancing the science and the processes and the devices and the platforms and the tools and the infrastructure so as to deliver, free, the miracle of modern programmable logic, that empowers even the little guy to turn ideas into tangible hardware.

And I thank you, dear reader, for frequenting this site, warts and all.

New Xilinx Spartan-IIE devices — like manna from heaven
In September, Altera announced Cyclone, and last November, Xilinx announced Spartan-IIE.  Back then I wrote,

“You might think that as Virtex-E is to Virtex, so is Spartan-IIE to Spartan-II.””But you would be wrong.  According to data sheets, whereas an XCV200 has 14 BRAMs (56 Kb) and the XCV200E has 28 BRAMs (112 Kb), in the Spartan-II/E family, both the XC2S200 and (alas)the XC2S200E have the same 14 BRAMs (56 Kb).”

“If your work is “BRAM bound”, as is my multiprocessor research, this is a disappointment.”

Now Xilinx announces two new, larger Spartan-IIE devices, the XC2S400E and XC2S600E.  And lo and behold, unlike the BRAM deficient XC2S300E, the 2S400E and 2S600E have the same BRAM to LUT ratios as the original V400E and V600E.  Thanks Xilinx!

A good thing too, for otherwise these parts would be seriously RAM poor vis-a-vis their Cyclone competition.

Xilinx: … Extends World’s Lowest Cost FPGA Product Line.FAQ.Data sheet (alas, no single PDF).

“In 2003, the company is on track to deliver a fifth generation of the Spartan Series, reaching even higher densities at significantly lower price points.”

Here is the updated competitive landscape. Since Xilinx is making a big noise about the greater number of I/Os available with Spartan-IIE devices (an observation first noted by Rick “rickman” Collins), I thought I would oblige them and add a column for I/O.

(The concept of the Cyclone parts, as I understand it, is the pad ring limits determine the area of the device and hence the area for the programmable logic fabric.  So what, then, does the higher ratio of I/O to logic in the Xilinx devices tell us?)

 BRAM 02 03 04 03 Device Kb KLUT I/O BAP BAP BAP Ref $/KLUT
XCS05XL     0    0.2   77 $2.5         [3] $12.75
XC2S50E    32    1.5  182   $7         [2]  $4.67
EP1C3      52      3  104       $7  $4 [1]  $2.33
EP1C6      80      6  185      $17  $9 [1]  $2.83
XC2S300E   64      6  329  $18         [2]  $3.00
XC2S400E  160     10  410      $27     [4]  $2.70
EP1C12    208     12  249      $35 $25 [1]  $2.92
XC2S600E  288     14  514      $45     [4]  $3.26
EP1C20    256     20  301      $60 $40 [1]  $3.21
XC2V1000  640     10
EP1S10    752     11
EP1S20   1352     18
XC2V2000  896     22
 
BRAM Kb: Kbits of block RAM
         (excludes parity bits, LUT RAM, and "M512s")
KLUTs:   thousands of LUTs
I/O:     maximum user I/O
BAP:     approximate best announced price, any volume
$/KLUT:  approximate 2003 BAP/KLUTs

References:

[1] Altera Cyclone Q&A:“High-volume pricing (250,000 units) in 2004 for the EP1C3, EP1C6, EP1C12, and EP1C20 devices in the smallest package and slowest speed grade will start at $4, $8.95, $25, and $40, respectively. … Pricing for 50,000 units in mid-2003 for the EP1C3, EP1C6, EP1C12, and EP1C20 devices in the smallest package and slowest speed grade will start at $7, $17, $35, and $60, respectively.”

[2] Xilinx Spartan-IIE press release:“Second half 2002 pricing ranges from $6.95 for the XC2S50E- TQ144 (50,000 system gates) to $17.95 for the XC2S300E-PQ208 (300,000 system gates) in volumes greater than 250,000 units.”

[3] Xilinx Spartan prelease:“Spartan pricing ranges from $2.55 for the XCSO5XL-VQ100 (5,000 system gates) to $17.95 for the XC2S300E-PQ208 (300,000 system gates) in volumes greater than 250,000 units.”

[4] Xilinx 2nd Spartan-IIE press release:“XC2S400E … and XC2S600E … and are priced at $27 and $45 respectively (250K volume).”

Other reports Anthony Cataldo, EE Times: Xilinx packs more I/O into its top-selling FPGA line.

Crista Souza, EBN: Xilinx drives Spartan-IIE to high end.

Peter Clarke, Semiconductor Business News: Xilinx adds two FPGAs to Spartan family.

(I think it is interesting to note that no one else picked up on the much more generous servings of BRAM ports and bits in the newer devices.)

What XC2S600E means to me Please refer back to this piece that sketches how in April ’01 I PAR’d a multiprocessor of 12 clusters of 5 processors in a single V600E, using 1 1/5 BRAMs per processor.

At the time, the V600E was not inexpensive.

Now with the advent of the XC2S600E, we can see practical and inexpensive supercomputer scale meshes of simple processing elements implemented completely and cost effectively in programmable logic.

At 60 processors per $45 device (in huge volumes), that works out to just $0.75 per processing element.  Loaded up with DRAM, this implies a total component cost of ~$1.50/PE, and a density of about 20-40 processors per square inch.

[comp.arch.fpga] Why FPGA CPUs?

Subject: Re: Minimal ALU instruction set.
Date: 19 May 1998 00:00:00 GMT
Newsgroups: comp.arch,comp.arch.fpga,comp.arch.embedded

Peter wrote in message <3561443d.214920709@news.netcomuk.co.uk>...
>
>I may have missed the original post, but may I ask why anyone wants to
>do this project? Is it just an exercise?

>
>Many people have thought about doing a CPU in an FPGA, but AFAIK it is
>always a futile exercise because one can buy a CPU with a given
>capability for far less than the cost of the FPGA.

You're right. But what fun! I used to envy processor designers in industry
and academia. Now I can do my own processors, on-chip peripherals, cache,
etc. In fact, I have it far better. I can design the entire system, the
ISA, the microarchitecture, and get working hardware in a few days. In
contrast, the typical big company CPU designer works for months at a stretch
on a small piece of a huge and complex system. And there is a certain
pleasure in minimalism and self-sufficiency.

It is one thing to read about simple microarchitectures in H&P, it is
another to go build and debug and boot them. You can "squish the CLBs
between your toes" -- you become familiar with the same pipe stages, clock
speed, area, IPC tradeoffs, although your units are CLBs and ns rather than
rbes and ps.

The resulting designs are only as fast as seven year old commodity
processors, but that's OK. Maybe 20X a VAX is fast enough for your
application -- you don't need 200X a VAX. And whether you have a StrongARM,
an R4640, or a custom FPGA CPU, you are using the same external memory, more
or less -- cache misses still cost 100 ns.

True, commodity processors are cheaper on an absolute basis, especially if
you don't take into account total system cost. But FPGA prices are coming
down. By end of 1998, the Xilinx XCS20 will be $6.50 Q100K (ref:
http://www.xilinx.com/prs_rls/spartan.htm). This part, equivalent to the
XC4010 that hosts the J32 (1995), can implement a 33 MHz conventional
pipelined 32-bit RISC processor leaving 5,000 gates of logic for
system-on-chip peripherals. You will soon be able to build highly
integrated and customized glueless systems with just FPGA+SDRAM for ~$10.
And there is the soon-to-be-$3 XCS05, adequate for a nice little 10 MIPS
16-bit processor with logic to spare.

Implications/Predictions
(some from other folks)

* falling FPGA prices will eventually clamp an upper bound on the price of
many custom parts, including embedded CPUs

* RISC CPU design is no longer rocket science -- HDLs, tools, and the FPGA's
abstraction of all the hard EE, means that undergrads will increasingly
design their own processors. Of course, these designs will never complete
with commodity microprocessors for specmarks.

* a number of these designs will be published under GPL or put in the public
domain. There will be communities of users of certain free CPU designs,
similar to the open software movement. There will be GCC tools chains,
lunatic fringe Linux ports, etc.

* there will be free implementations of legacy ISAs. Or perhaps free
implementations of cross-assemblers/cross-loaders from legacy ISAs to
simplified minimalist FPGA CPU ISAs.

* embedded CPU vendors will start to ship with some FPGA on chip (Motorola
and Atmel have announced this).

Jan Gray
(J32 described at http://www3.sympatico.ca/jsgray/homebrew.htm)