[geeks] WANTED: chip level design software for UNIX/Linux

[Geoffrey S. Mendelson]

On Wed, May 09, 2007 at 08:12:15PM -0400, Charles Shannon Hendrix wrote:
> I've been playing with more low level toys lately, so I have some
> questions about learning small computers.  I know that Bill mentioned
> Z80 stuff in the past and some of the rest of you, so I figure you'll
> have some ideas at least.

I have some suggestions:

1. Look at the following: I was looking at them for using on my MAC and for
   analog circuts, but some have Windows or Linux versions, are free or
   cheap for students (including self-educating ones).

	http://www.swcp.com/~jchavez/osmond.html
	http://www.mccad.com/
	http://geda.seul.org/
 
	There are also some DOS programs that work pretty well and are
	free, but I've lost touch with them.

2. Ask around in the computer experimenter and HAM community and see if there
   is someone local who does one-off boards for experimenters. They may
   suggest a program for you to use. 

3, Look at the Z8. It's still in use as a microcontroller, there are
   lots of documents, projects, and programing for it. You can download
   PDF files of all the documents, a free software development kit,
   and last I checked buy a simple test kit for about $40.

   There are many versions of the chip, and I expect you can get one
   with I/O, a ROM monitor and RAM as a package for the development
   kit.



> First thing: I'm going back and relearning basic computer circuits. I
> can't really afford to set up the real hardware since I've gradually
> thinned out my parts over the last 15 years.

Things have changed, you don't need a lot of hardware. There are zillions
of emebeded chips, development tools and systems available now. Microprocessors
are so cheap and powerfull these days that ASIC (application specific IC)
design is becoming a lost art.

Almost five years ago I was taught a hard lesson that ASIC designs for
startups was a good way to schnoor millions of dollars of development
money from unsophisticaed investors. By then 99% of what was being done
in ASIC work could have been done with an emebeded processor and a few
thousand dollars worth of development tools. More than half for a
few hundred dollars in tools, or less.

Old chips live on in cheap low power versions. One famous ham radio
company uses a top of the line embeded CPU in their latest $5,000 radio.
If you look it up it's really a small footprint, SMT, low power
version of the 68000. Of course now it's made by FreeScale instead
of Motorola (they spun off the semiconductor divsion) and has a 
fancy name, but it does the same things, in exactly the same way
as the 68000 in my Mac/SE from 1988.



> In college we used Cadence, but that was mega expensive back then, and I
> imagine still would be.

You should contact the company they may have a student version or
a demo you can use. 

> Almost forgot... I have a lot of Forest Mims books on circuitry.  One
> set I seem to have lost was where he gave the basics of a 4-bit computer
> system.  I recall it was his usual clear style.

Forest Mims, the inventor of fiber optic communication. I still have
and love his basic circuit books. Don't forget Don Lancaster too.

http://en.wikipedia.org/wiki/Don_Lancaster 

> Does anyone know of a reference like that, except covering 8 and/or 16
> bit circuits? I know you can learn and expand on the 4-bit systems, but
> it might be easier to start with them.

Lancaster's "TTL Cookbook"? Didn't he do one for microprocessors. 


Lancaster has a web site: http://www.tinaja.com/


> I'm looking for recommendations on trainer systems.  Primary interests
> are 8-bit micros, and maybe 32-bit MIPS.
> 
> So far what I've found is pretty expensive, at least for me right now.

Again, ask. Sometimes the companies will provide you with free tech
support, samples, etc. AMD and Intel have wonderful developer support
programs, you have to sign up (free) and sign an NDA for access to
information on unreleased products. 

Since you don't care about them, you probably can dispense with the NDA.

AMD bought the National Semiconductor line of GEODE chips in 2003 and
has done well for them. New chips, better support etc. They have
both X86 and ARM versions.

So does Intel. 

Another thing you can do is collect broken iPods and Palm pilots.
iPods, etc use ARM processors, Palms, 68000. Pocket PCs use ARMs too.

Lots of good parts if you can learn how to remove and re-use SMD
devices. If you are bad at it and destroy 99% of them, the price is 
right anyway. :-)

I've played with several projects that would have been built on recycled
iPods. Unfortunately they never got off the ground, but I had a lot
of that in the last year.

Geoff.

-- 
Geoffrey S. Mendelson, Jerusalem, Israel gsm at mendelson.com  N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838 
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