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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!"
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.
However, anything close to being as complex as Intel/AMD chips requires an army of highly experienced architects/engineers with many of them having pHD's. Even the software design tools, such as Mentor, cost well over $100,000
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.
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).
Sure you can outsource. Practically all design houses outsorce fabbing (current estimates indicate that you need a turnaround of approx $7 billion to justify your own fab)
As a small time operator no fab is going to talk to you however. You are going to go through a middleman (just as well since these often supply design services like P&R(Place and route) and synthesis, withouth these services you'll be looking at a investment at approx $200 000 in tools)
For a pure digital diesign you can then get away with a tool investment of $2-5000 for simulation.
For fabbing you should expect $20-50000 in expenses to ready your design for tape-out. The cost of the manufacture will depend of wether you are going for an engineering run of MPW (Multi Project Wafer). An MPW will cost you $10-100 000 depending on process sophistication and size and yield 10-200 chips. An engineering run requires a dedicated mask set which will cost $100-500 000. The engineering run itself is consisderably cheaper and the masks may be reused for manufacture.
If you are going to do any leading edge design you will however need to do your own synthesis and P&R. If you target 0.18um of better you propably are going to need som degree of physical synthesis capability ($100000 and up). Fo manufacture you will also need to prepare a test procedure (ATPG tools (Automatic Test Pattern Generator) check in at approx $100000)
Also remeber that all tools will usually require a maintenance fee of 10-20% annually of purchase price (pays for upgrades and support)
At last don't forget computer hardware to run your tools on. Linux suffices for most tools, but some will only run on Sun/HP workstations.
Prototyping can be done much cheaper through MOSIS. If you just want to play with a simple processor (say an 8 bit processor in the 0.5 micron process) you can get in the game for $5,900 US. If you want to play in a 32-bit world, but don't need the hottest process, big onboard cache, etc., consider $15,500 US for 40 parts in a 0.25 micron TSMC process.
In amy case, the real advantage to a roll-your-own processor is not to build a better general purpose processor better than P4/SPARC/ARM/MIPS/PPC but to create a special purpose processor that does the one thing you care most about very well.
No electrons were harmed creating this post, though some may have been subjected to electrical and/or magnetic fields.
I agree with most of your points but the ARM is an interesting counter-example. It was designed by four or five guys at Acorn Computers in the UK. They had just been told to sod off by Intel when they wanted to license the 8086 as a base design. It took about five man years of work - five guys working for just under a year - everything worked first time when plugged in (including all the IO and the peripherals), and they got around the manufacturing problem by licensing the design to OEMs who wanted to embed it. It was (and is) a joy to program for, has very low power consumption and is easily extensible.
In a supreme irony, Intel ended up licensing the ARM from Acorn RISC machines in the early 90s. Right now ARMs are everywhere - PDAs, cellphones, routers and switches. Now of course a 200Mhz ARM running in an iPAQ is a little less complex than a modern P4 with SSE 2 and all its other bells and whistles, but it's close. I think its encouraging that designing a successful microprocessor has been shown to be not solely the domain of giant corporations with billions of dollars in fabs and armies of PHD-wielding staff.
--- Hot Shot City is particularly good.