Design Your Very Own Microprocessor

LightJockey writes: "CircuitCellar has a great article on designing and building your own microprocessor using FPGAs and openly available processor designs, ranging from ARM and MIPS based to custom designs, and even a couple SPARC based chips, and also a really cool 'processor toaster,' start with a base processor design, and using a webpage to select upgraded components, it spits out the VHDL file you need to create it. Brings garage hackerdom up to a whole new level!"

Comments

Amateur chip designers

[ObviousGuy]

Without training and experience in hardware design at the college level, it is doubtful that any amateur could come up with a design that improved on existing chip designs or create a fundamentally new design that would be of interest to chip companies.

The hope springs eternal, though.

Re:Amateur chip designers

[MoneyT]

I could swear I read something about this being the reaction Steve & Steve got from people about home computers. Too complex to buid a useful computer, never be able to compete with the big guys. Guess they were wrong too.

Besides, I wouldn't be aiming to build a computer processor. I'd just wna tto build a processor that could process something.

Re:Amateur chip designers

[raytracer]

Designing a modern microprocessor can not be done by amateurs or a group of people with a B.S. degrees in electrical engineering. Sure, many of us have taken undergraduate architecture classes and maybe have designed a simple pipelined microprocessor in Mentor Graphics or VHDL/Verilog. Some of us maybe even implemented it with FPGAs.

This is either irrelevant or just stupid, depending on how you look at it,

It is true that no amateurs are going to build their own 747 either, but there are no lack of people who build their own planes and gliders. Using FPGAsof modest cost, amateurs can implement processors which are perhaps 8 years back in the power curve. I don't know about you, but I found the computer that I owned 8 years ago to be quite a useful gadget. The ability to reprogram the core of your microprocessor to (say) add new instructions, peripherals and capabilities seems to be a cool one. As the FPGA industry moves forward, experimenters in this technology will also track Moore's law improvements. Yes, they will always be behind what billion dollar fabs can produce, but I fail to see why this is a problem for amateur chip designers.

Microprocessors are becoming so complex to design and build, that only a few companies are surviving. Sort of like the aircraft industry. There are only 2 remaining companies in this world that design and build 300+ passenger commercial aircraft (Boeing and Airbus). It is infeasible for a new competitor to arise because of the capital involved (unless of course it is nationally sponsored).

Again, so what? We were talking about amateur designs, not going into competition with Intel and AMD. I imagine that Linus heard similar arguments about the infeasibility of writing his own operating system.

Linus took the wide availability of inexpensive PC computers and leveraged those to create a new operating system. Amateur FPGA designers could try to leverage the availability of inexpensive FPGA chips to design their own processors. If you asked me the likelihood that anyone would be using them in a commercial environment a year from now, I'd say it was pretty low, but in a ten year time span....

Re:Amateur chip designers

[kilrogg]

Then building the chip is another beast requiring a fab facility in the order of $1 billion for any process with feature sizes smaller than 0.5.

You don't need to build your own fab, there are fabs out there that will gladly build your IC for you, the most popular being TSMC. Many companies use external fabs (so called "fabless" semiconductor companies), including house hold names like Nvidia or ATI.

Mind you its still expensive as hell (0.25 ~ 1million US$ for your own mask set for an advanced process) which is why many amatures use FPGAs instead.

Point of FPGA processors

[brejc8]

The whole point of having an FPGA implementation is to allow you to get the latest version of the processor with a patch debug or improvement. Imagine compiling the latest distribution down to your processor and off you go. If you want it to do something special then hack the code.
www.opencores.org has many processors allready. I made a MIPS R3000 with a cache and MMU etc with minimal knowledge of hardware design.

Don't have to make the new Intel chip...

[fcrick]

I took a class in college where we learned how do this, with the last assignment ending with implementing a processor with 12 or so instructions.

The one thing I think I came away with is that you can built just about anything with FPGA's, whether you mean CPU's, or just controllers for large LED's, garage door openers, mp3 players or whatever...

There is a huge gap to fill in terms of geeks designing neat household or hobby chips that just do something that you need to implement in hardware (or firmware i guess). These devices don't need to be as fast as Intel or something, but there can certainly do something Intel's never done. I've always wondered why there aren't more open source projects built on this idea...any know? Anyone know where to look for these projects?

I guess a reality to recognize is that miniaturization (sp?) and faster processors with more features will eventually drive almost everything into the software arena (arguably already happened), so you might as well just write your cool device in and run it on your Linux iPaq or whatever replaces it...

Of course, I'm far from being an expert in this arena so this is just amatuer speculation...

Companies take this stuff seriously.

[brejc8]

When I made my MIPS clone MIPS hot straight on my back sending me many threatening letters. Firstly they wanted to make sure I wasn't breaking any of their IPs. Then they wanted me to place a massive blurb to state I want anything to do with their company. Then they went down to the level of requesting my report of the building of this processor to use mips and a perfect adjective rather than a noun. Each time recommending that it would me much easier if I just gave up and took it off the web.

Hate to say it, but this won't fly...

[redhatbox]

NOTE TO MODERATORS: Yeah, this is off-topic, but comes up often enough that I thought I'd take a stab at it anyhow. Thanks.

This would probably make a lot of people angry. Your motives are great; you want the subscriber base of /. to enjoy the articles, without having to brutally flood some guy's server(s).

Trouble is, a lot of sites look to ad revenue to pay for at least some of the cost of hosting and bandwidth. If you mirror the article, most ad systems are "cut out of the equation." Now, this is sounding better and better for /. readers, but not so hot for the site operators' bottom lines. Even if the server goes down, the revenue from our traffic may be well worth the downtime (depending on the site, of course).

Maybe mirroring of academic articles (without ads or other profit-generation methods) would be appropriate, though. Or, maybe /. could try to contact a site owner prior to posting an article. Say, give the owner a couple of hours advance notice, and let the guy decide for himself if he'd rather be mirrored or /.'ed.

Just a few thought. :)

Re:FPGAs

[svirre]

Right. You do _not_ want to deped on the supplied xilinx software for synthesis. It's pretty much crap. Use Synplicity or Leonardo Spectrum (to be replaced with Precicion synthesis this summer) instead.

Also, you do most definetly not want to design your circuit graphically. The time you are going to use to draw a single state machine graphically, I will have designed the whole circuit. Graphical design tools are OK for the structural design phase (this is however a miniscule part of the whole process), otherwise they ar pretty much toys. The best digital hardware design tool availible is Emacs.

Once you have learnt hardware design, and understood the difference between a programming language and a hardware description language, VHDL is quite easy to deal with (I don't know much verilog, and from what I have see I don't want to deal with it. It's a verification hell)

Open Source Hardware

[Niscenus]

I had an article on this awhile back ago (toasted like AlaskanUnderachiever's previous four AMD's), but with the site now gone, I can't seem to find it in either google or wayback.

Anyhow, I think it is important that even hardware move over to the open source world. There are three requirements for this to kick off:

An inexpensive system for creating them

Knowledge and understanding of the standards involved

A central repository for updating and dissemination

If a common public utility for creating wafers could come out at fair cost (say, atleast equal to a computer, estimate $800 or so) that would be a major step for the first part. If the group involved at the IEEE for processor standards could freely distribute some or all of the necessary information, similar to as PARC did with POSIX, that would assist in the second. Finally, we would need a FreshMeat equivelant for hardware designs.

Processors are only a beginning...solid state technology, drives and cards would come fast thereafter. Is it an emerging field or something that will remain in the hands of the elite few who actually know the difference between a PSU and an FPU? I can wait you people out...I've been waiting out for the creation of massively distributed Open Source Software before many of you were born!

Re:Open Source Hardware

[sunspot55]

An inexpensive system for creating them

Good luck.. as a fab engineer I can attest that the last thing companies want to do is to make a die for every Joe Schmoe that comes along. The name of the game in fab is yield, yield, yield. As like a recipe for different cakes, each chip design has it's own recipe that must have the kinks worked out of. There is an enormous ammount of overhead going into starting a process and an enormous ammount of money going into improving the yield of a process. In short, the companies care about the bottom line, and unless people had millions to pony up for their custom designs it isn't going to be happening anytime soon. A company isn't going to let hundreds of millions of dollars of equipment run Joe Schmoe's home grown microprocessor when they could be churning out far more profitable Pentiums, etc. It's just like Boeing or Airbus, as someone mentioned earlier. Boeing can't afford to build a plane from scratch (ie VHDL) for everyone who had $800, it's just not feasible.