AMD CPU Reccommendations?

[beet1e]

Horn,

I read the article whose link you posted, and I now see that the article I must have read was the 1997 TIME Man of the Year profile. Gawd, was it that long ago?!

[bloom25]

Yes, I meant gate length...  (I'm pretty bad at reading over my posts to make sure I didn't mess up something simple. )  I hate to admit it, but most of my knowledge is based on work with a .5um (HP) and .35um (TSMC) process, so I'm not totally clued in on particular issues dealing with newer processes.  With these two processes, the .5 um, for example, refered to the minimum gate length, and the minimum spacing between contacts and metal layers was .25 um (if I remember right).  You don't really have to worry about it, because when you run DRC (design rule check) it will tell you if you violated any design rules for that particular process.  

Beet1e, most of the stuff I've learned has been through CPU architecture classes, digital logic design classes (most of my interests are in ASIC design which are coded in VHDL, but many of the concepts hold true for both CPUs and Asics), and a LOT of personal interest in the area that give me the drive to actually attempt to "read" books on the subject. I've also done some work with various microcontrollers (Intel 8051/8031, PICs, etc).  (Trust me, engineering books are neither easy to read and really aren't the slightest amount of fun either... )  

If you want a general overview at a slightly higher level than what I posted above, I think there are some good articles at http://www.arstechnica.com .  (Animal posted a link to that site, and I think there were some articles there about the K7 (Athlon) core.  I don't know how accurate it is, but from the few articles I looked at it looked pretty good.)

Most of the design I do (unless it's very basic) is actually done via a programming language called VHDL.  This language is similar to C in structure, and is very easy to read if you have any knowledge in programming. It allows you to define "components" which are somewhat similar to objects in other programming languages (Java comes to mind). It allows you to remove yourself to some degree from the actual hardware and focus more on behavioral aspects.  For example, given the correct library for the type of logic gates you are using, you can just type: a <= vector1 + vector2; and when this code is compiled and synthesized you will actually get an adder (what type depends on whether you wanted it optimized for speed or area).  You can do structural coding as well, and the synthesis tool will make a number of optimizations for you if you code it correctly.  (And gates replaced with Nand gates, ors with nors, etc)  

This language was developed for the DoD and the first version became available in 1987 (VHDL '87), it was revised in 1993.  There is some current work to extend it to analog circuits as well.  Nearly ALL Asic (application specific integrated circuits) designs are now done to some degree using VHDL or Verilog (similar to VHDL, but not as good IMO).

[bloom25]

I'm not sure if this is what you were getting at Skuzzy, but I can tell you that the interconnects themselves account for much of the delay in modern circuits.  As with just about everything else, it all comes back around to RC basics.

These lines have fairly high resistances, and there is often considerable capacitive coupling between metal layers.  (I was looking for some exact values, but I didn't find anything new enough to be very useful.)  It's also worth noting that the contacts themselves have considerable resistance, and unfortuantely that varies widely.  (For the HP .5 um process I did a cascode amplifier design with, I'm thinking it was between 25 - 100 Ohms per contact. )

[Skuzzy]

Close enough bloom.

I got out of hardware design when I realized TTL designs were going the way of the dinosaur.  I did a few ASIC's, and many PAL's, but found the work rather boring.  As a matter of fact, that is one of the reasons I got into software design.  I found it much easier to write the simulation software for the hardware designs and much more mentally challenging.  I wrote a circuit design simulation tool when I was doing those ASIC's and PAL's which allowed me to do basically one shot designs.  Made it really boring after that though, but allowed me to migrate into software design.

I still keep my hand in it, by doing work around the house.  My cat door was a fun project.  I built a 4 bit microprocessor which controls the cats door.
Attached a magnet to her collar and when she comes within 6 inches of the door, it opens for her.  Pretty basic sensing device coupled with some digital controls for the servo stepper that operates the door.
Hehe, I probably have about 5 thousand transistors in use in my home for all the things I have built.

Still, I like to keep my feet in it all.  Of course, I dont find engineering manuals boring at all.  They fascinate me.  Most people would find them incredibly boring though.  I remember getting my first TTL logic parts manual from TI.  Thought I was in heaven.