Blast from the past... Z80!

Ooooooh! Joerg ought to just love that site... look at all that scripting ;-)

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food

Now, we will be using MRAM.

Courtesy of Freescale

All kinds of chips that you think are gone are likely still available.

I would be wary of your 'distributor' if he comes back with crap responses like that.

Didn't you just say you can't get them? D'oh! Time is not even in that formula.

Not only that i know two other architectures that have such prefix / instructions. There may be more.

You ain't the only one. Never got to build my bit slice machine though. Strange, it influenced the design of many machines along the way.

Maybe i hit them at a bad time, but it is the worst pig dog slow site i have seen for months. I have about 1.5 Mb/s download, but it took over a minute to load, and was crap slow afterwards. That got my attention, negatively.

...and you were from Florida with the name of "chad"...

*my* bit slice didn't get built. Somebody else's did. I also consulted to someone building a 3rd one that I can't go into.

I also did a machine that was a lot like a bit slice that didn't really have an ALU. It was a system that needed to read a bunch of bytes from memory and rearrange the nibbles quickly. The idea of using a registered PROM and a counter to make logic signals has popped up many times.

[... computer stuff ...]

I know someone called Chad. He didn't like hearing about all the hanging chad.

BTW: The term chad got attached because a guy named Chadless invented one that only cut 3 sided and folded the bit of paper over. People mistook it for being a name for one that doesn't make chad and thuse the little bits must be chad.

Hm... I remember that the microcode for the S360/30 was suppied as CCROS (silver(?)-coated mylar(?) capacitor arrays) and the S360/40 used TROS (transformer "loops" embedded in thin plastic strips). You could modify the CCROS cards with an 026/029 keypunch, but you needed a special leather-hole-punch-like tool to "program" the TROS strips.

WCS (writeable, loaded from floppy) was present on the S370/158 and possibly the S360/67, but I'm sure there were other wild and wonderful variants.

Ah, the joys of nostalgia.

Frank McKenney

-- I do not deny that laws are important, but...the passage of new laws has continually served as a substitute for thought. -- Aldo Leopold

-- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney ayut mined spring dawt cahm (y'all)

The 360/75 (and the /195, IIRC) was hardwired. No microcode at all.

History lessons. ;-)

Ahhh. Primitive state machines. Another useful tool that has been around a while. Some of the current tools for state machines help you set up multiple interacting state machines. Now that can be fun.

e

The project I am working on has multiple state machines in the micro. They still make a great way to arrange the problem to be solved.

Some years back, these guys showed up trying to sell a state machine based product development tool for products. It was a very clever scam. Among their claims was that their product output C code that was 100% if your design was correct in their tool. When I got into the details, I discovered that to develop you wrote stuff like:

if (some expression) tra-la-tra-la { Some code to do tra-la-tra-la }

they then ran using that code. When it came time to output, they just had to strip out the "tra-la-tra-la". I spent a weekend and made a more useful tool. Their's required you to basically write your application before you could show what it did to marketing. Mine made a very quick fake up of the user interface with a lot less code.

These days, wouldn't you just plop a Z80 core into an FPGA or whatever?

Cheers! Rich

3898-ND

No. I wouldn't waste the transistors on a Z80. ;-) =20

FPGAs still cost real money and there are far better solutions. I=20 also wouldn't use an unsupported tool chain.

...

You can do that or you could put a part like the 180 or a Rabbit on the board and perhaps not need as large of an FPGA. Everybody and their dog makes compilers etc for them. With using a real chip, you can use one of the in-circuit-emulators to verify your design. With the FPGA based CPU, you have to build in some hooks for debuging.

Variations of Dan Bricklin's "Demo" program of old in there somewhere?

I might do that, or a different core, or no core at all, or an external micro, or something different. Depends on what i conclude the is right solution to the task / problem / opportunity at hand. Now how about the miserable slowness of the site i experienced?

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No, it was a very simple program hunked together from code I had written for other purposes and some new code. Basically it took in some simple ASCII files and made a picture on the screen that you could then click on.

The first file described the outline of the front panel, the outline of the display and the outlines of all of the buttons. The graphics was done with a palette so that each button was a "different color" even if the colors were the same. This let me easily know which button the cursor was over.

The second file contained a list of all the states in the form of:

STATE StateName ON Button1 OtherState ON Button2 DifferentState Text X Y "Hi there the power is now on" END

There were some special cases like the position an nature of the cursor that had their own keywords.