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How hard is to build a processor?

D

Don McKenzie

Jan 1, 1970
0
It seems that “Google” engineer Bill Buzbee isn’t interested in
microprocessors that can be purchased in marked. There is more fun to
build own. Several years ago he built first “Magic-1” processors
, but now he makes its documentations widely available in his project
website.

http://www.embedds.com/how-hard-is-to-build-a-processor/


Cheers Don...


--
Don McKenzie

Site Map: http://www.dontronics.com/sitemap
E-Mail Contact Page: http://www.dontronics.com/email
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Product Sellout: 15% OFF 4DSystems OLED Displays & modules.
http://www.dontronics-shop.com/micro-oled.html
 
F

fritz

Jan 1, 1970
0
Don McKenzie said:
It seems that “Google” engineer Bill Buzbee isn’t interested in
microprocessors that can be purchased in marked. There is more fun to
build own. Several years ago he built first “Magic-1” processors
, but now he makes its documentations widely available in his project
website.

http://www.embedds.com/how-hard-is-to-build-a-processor/

Why not ?
Someone should be keeping the old craft alive. Good on him !
You could ask 'why build museums' ?
I think you agree.
 
J

Jon Kirwan

Jan 1, 1970
0
It seems that “Google” engineer Bill Buzbee isn’t interested in
microprocessors that can be purchased in marked. There is more fun to
build own. Several years ago he built first “Magic-1” processors
, but now he makes its documentations widely available in his project
website.

http://www.embedds.com/how-hard-is-to-build-a-processor/


Cheers Don...

Thanks, Don. I absolutely LOVE doing this kind of thing. It
should be required work for anyone in embedded programming,
at least. 35 years ago I tried my hand at it and failed to
get much useful. It wasn't until I later got access to a
logic simulator that I was finally able to complete a
successful processor design with 7400 logic, not using the
74181 ALU by the way, though I never built what seemed to
work so well. Later, I picked up a Xilinx 4000 series demo
board and, for the very first time, learned to write VHDL and
finally coded up my first processor that worked!!! (I didn't
do the floorplanning by hand -- way over my head at the
time.)

I learned so much doing this, though.

Anyway, thanks for the link!!

Jon
 
P

petrus bitbyter

Jan 1, 1970
0
Don McKenzie said:
It seems that “Google” engineer Bill Buzbee isn’t interested in
microprocessors that can be purchased in marked. There is more fun to
build own. Several years ago he built first “Magic-1” processors
, but now he makes its documentations widely available in his project
website.

http://www.embedds.com/how-hard-is-to-build-a-processor/


Cheers Don...


--
Don McKenzie

Site Map: http://www.dontronics.com/sitemap
E-Mail Contact Page: http://www.dontronics.com/email
Web Camera Page: http://www.dontronics.com/webcam
No More Damn Spam: http://www.dontronics.com/spam

Product Sellout: 15% OFF 4DSystems OLED Displays & modules.
http://www.dontronics-shop.com/micro-oled.html


Back in '74 Elektor published a design of a computer built with TTL-logic.
They really made it work though I doubt any subscriber built it too.

petrus bitbyter
 
J

Joe Pfeiffer

Jan 1, 1970
0
Cool! Over on alt.folklore.computers there was a recent thread about
projects implementing old CPUs with an FPGA. Very neat stuff out there
for the retrocomputing world.
 
I

Ian Bell

Jan 1, 1970
0
petrus said:
Back in '74 Elektor published a design of a computer built with TTL-logic.
They really made it work though I doubt any subscriber built it too.

petrus bitbyter

Back in '73 I worked on a 16 bit mini computer built entirely out of
TTL, complete with a row of toggle switches on the front panel so you
could enter machine code by hand. It had a paper tape reader and along
with a paper tape punch you could use the two pass assembler - that's a
lot of paper.

Cheers

ian
 
T

Tim Watts

Jan 1, 1970
0
That reminds me that there are some excellent course videos by David
Culler of Berkeley showing how to build a CPU from logic gates. A bit
of searching for his webcasts for course 61CL Fall 2009 in H.264 video
should bring them up.

I had no idea until working through the lectures that *I* could build
a CPU using components I already knew about. As part of the course he
shows how to do so by working up from logic gates.

James

I knew a chap (York University Computing Services) who claimed to have a
mate who built an elementary CPU from fruit machine relays[1]. Occupied a
bit of board about one square yard. He lost interest in building RAM from
more relays, so wedged a 1k RAM chip with suitable interfacing on the side.
Ran at about 1 IPS apparently...

[1] he got a box load from a surplus store, old stripped out ones. Had an
unusual contact configuration that made them quite suitable.
 
W

Walter Banks

Jan 1, 1970
0
Don said:
It seems that “Google” engineer Bill Buzbee isn’t interested in
microprocessors that can be purchased in marked. There is more fun to
build own. Several years ago he built first “Magic-1” processors
, but now he makes its documentations widely available in his project
website.

http://www.embedds.com/how-hard-is-to-build-a-processor/

It is a lost art. In the 70's I taught a course that students built
a small computer out of lab modules of TTL chip's. My first
personal computer was micro coded PDP-8 hand built.

Ram was 1K (bits) parts on a wirewrap board.

Walter..
 
J

Jon Kirwan

Jan 1, 1970
0
It is a lost art. In the 70's I taught a course that students built
a small computer out of lab modules of TTL chip's. My first
personal computer was micro coded PDP-8 hand built.

Ram was 1K (bits) parts on a wirewrap board.

Walter..

Oh, my, Walter. That would have been a wonderful class to
have taken. I only wish...

Jon
 
B

Bill Cooke

Jan 1, 1970
0
Walter said:
It is a lost art. In the 70's I taught a course that students built
a small computer out of lab modules of TTL chip's. My first
personal computer was micro coded PDP-8 hand built.

Ram was 1K (bits) parts on a wirewrap board.

Walter..
In 1961 a colleague told me of a machine in a lab at Cornell named
CADET, which reputedly stood for "can't add, doesn't even try". But it
was a universal (Turing) machine. Most everyone has stood on the
shoulders of software to extend behavior. In another sense, cpu
development has also stood on the shoulders of software arts, for needs
drive real engineering, not possibilities, and software disciplines
provide the languages for expressing these needs.

Each to his own. Some yearn to create a theory, some to create a
bridge, some to create an impression. I still ponder the structure of a
(programmable) computer of light and heavy marbles, gates, and a bunch
of elevators.

-- Bill Cooke
 
J

Joe Pfeiffer

Jan 1, 1970
0
Bill Cooke said:
In 1961 a colleague told me of a machine in a lab at Cornell named
CADET, which reputedly stood for "can't add, doesn't even try". But
it was a universal (Turing) machine. Most everyone has stood on the
shoulders of software to extend behavior. In another sense, cpu
development has also stood on the shoulders of software arts, for
needs drive real engineering, not possibilities, and software
disciplines provide the languages for expressing these needs.

IBM 1620. See http://en.wikipedia.org/wiki/IBM_1620
Each to his own. Some yearn to create a theory, some to create a
bridge, some to create an impression. I still ponder the structure of
a (programmable) computer of light and heavy marbles, gates, and a
bunch of elevators.

Another fun project!
 
S

Swanny

Jan 1, 1970
0
Walter said:
It is a lost art. In the 70's I taught a course that students built
a small computer out of lab modules of TTL chip's. My first
personal computer was micro coded PDP-8 hand built.

Ram was 1K (bits) parts on a wirewrap board.

Walter..

I wonder how many kiddies these days actually own a wirewrap tool?
 
D

D Yuniskis

Jan 1, 1970
0
Don said:
It seems that “Google” engineer Bill Buzbee isn’t interested in
microprocessors that can be purchased in marked. There is more fun to
build own. Several years ago he built first “Magic-1” processors
, but now he makes its documentations widely available in his project
website.

http://www.embedds.com/how-hard-is-to-build-a-processor/

In the early 80's it was common to build "custom" processors
out of 2900 bit-slice components. There was an excellent text
(and some good AMD appnotes) devoted entirely to this (Mick 'n'
Brick? yellow dust jacket).

In grade school, I build a combination (burglar) alarm using
(bistable?) inter-latching relays for the code store. With
a fire department klaxon as the annunciator (you *really*
didn't want to get the combination wrong! :> )

In high school, I built a two-player (offense + defense) football
(left-pondian football, that is :> ) game out of analog computers
(integrators, adders), DTL and VOM's (to display: "down", field
position, yards gained/lost on the play and yards 'til first down)
but that just ran at "DC". It was also quite large (4' x 8'
sheet of plywood to hold all the bits) and, thus, impractical
to preserve.

Many years ago, I built a "digital clock" out of relays. But,
it was very noisey and cost a fortune to keep replacing the
incandescent lamps used in the "7 segment" displays.

Now, I am much more fascinated by electro-mechanical *mechanisms*.
I have been working on a kinetic "sculpture" to act as a timepiece
in the back yard. A tribute to Rube Goldberg -- with the exception
that it must run *continuously* (most of his contraptions were
"one-shot" devices). But, in order to keep *good* time, I need
to "close the loop". Doing so without being noticed means
using some "non-discrete" device that you can control. I.e.,
something like a liquid whose rate of flow can be varied without
a critical observer being able to *easily* determine that this
is happening. Living in the DSw poses a problem using water as
it evaporates too fast (replenishing it from the domestic water
supply would be "cheating" :< ). I also need to locate some
larger solar panels so the device has no connection to the electric
utility.

I would also like to build a "Jetson's" style doorbell (though
programmable) to replace the electronic version I made some years
ago. But, apparently, the design of tubular bells is more art
than science (and, mistakes can be costly). So, I have a lot
more research to do. :<

"Toys" <grin>
 
D

D Yuniskis

Jan 1, 1970
0
TTman said:
But you have to add to that all the software to make it do something....
starting with a boot loader...

.... and there's the rub! :>

I designed a processor some years ago. A friend was responsible
for writing the code for it.

*Nothing* worked! :< This was completely unexpected as we were
both very competent in our individual responsibilities.

We soon realized that I had designed the instruction set expecting
"word" addresses (memory was 16b wide and only accessible *as* 16-bit
words -- hence it seemed *obvious* that addresses would be of "words")
whereas he had assumed *byte* addresses. :< Simple fix. Took
all of the drama out of the event! ;-)

I've seen other silly issues like this confound the initial
startup of custom processors: e.g., confusion over which
way the stack grows, whether the SP points to the last *used*
location on the stack or the next *available*, etc. They are
almost always "fun" problems to solve as they usually are
easy to find and have dramatic consequences once found!
 
J

Jon Kirwan

Jan 1, 1970
0
Hah! My leg's been pulled. and to think I'd just finished a year on
1401, 705 code! I'd thought 'cadet' was a lab project, not a for-real
machine. I've even read a 1620 manual, but never got to write for one.

-- Bill
<snip>

I can remember hearing that phrase from time to time when I
worked on the 1620. It was a fun machine. I used to swap
out the colored bezels on the control panel just to tease.

Jon
 
T

Thad Smith

Jan 1, 1970
0
I can remember hearing that phrase from time to time when I
worked on the 1620. It was a fun machine. I used to swap
out the colored bezels on the control panel just to tease.

I was working at a small shop that had a hand-me-down 1620. They had a simple
Fortran compiler, "PDQ Fortran", but it lacked some features they wanted. On my
own, I wrote a disassembler for the 1620, disassembled the compiler, studied the
code, figured out how to save some code space (memory was limited), then add
some features, basically enhanced write commands and formatting, all with no
external documentation. When the code was almost ready I was so excited I
couldn't sleep, so went into work at 4 AM or such and got it working. Fun days!
 
J

Joe Pfeiffer

Jan 1, 1970
0
D Yuniskis said:
In the early 80's it was common to build "custom" processors
out of 2900 bit-slice components. There was an excellent text
(and some good AMD appnotes) devoted entirely to this (Mick 'n'
Brick? yellow dust jacket).

Yes, Mick and Brick. An absolutely outstanding book on datapaths. and
microprogramming; it was all based on 2900-series, but the concepts
mapped to everything.
 
J

Joe Pfeiffer

Jan 1, 1970
0
The clock/calendar I hope to build over the next year or so will be
solar. The shadow of a post uniquely determines both date and time, if
you look at both angle and length....
 
D

D Yuniskis

Jan 1, 1970
0
Hi Rick,
Yup! I read Mick and Brick cover to cover and learned a lot from it.
I never built anything with bit slice other than on paper. But I have
a lot of respect for those who did. I even used a "high end"
workstation once that was a suped up 68000 made out of bit slice. I
think it had a marketing window of 15 minutes before Moto came out
with a 680xx or something much faster than the 68000.

AMD published a lot of app notes and manuals that really catered
to the 2900 family of devices. In my Great Databook Purge, they
are among the few items that I kept! (along with Mick 'n' Brick,
of course!)
I have thought about how to make a time piece that is actually
regulated by the flow of water. It would be hard to get this to be
accurate, but I havae some ideas on how to make it fairly good. I am

I plan on cheating: detecting the "displayed time" and using
that in a feedback loop to control the pump speed. It would
probably need to be a terribly overdamped control system
given all the other "cruft" between the pump and the
"display".
in the mid-east US, so we normally have lots of rain. I have thought
about ways to make it "self-winding". One is to simply catch rain
from the roof and keep the top reservoir full. Another would be to
use wind power to pump water from the lower reservoir to the top.

Yes, that's my approach. We don't have enough rainfall to
"self wind". I suspect it would be very difficult to keep
enough water in the system to span the gaps between rains!
(or, if you could keep enough water, trying to keep that water
"clean" of algae, etc. over that long of a time period).

We get *lots* of sun so PV seems to be an essential part
of any solution.
That would be doubly cool. It might even allow the clock hands to be
in front of the windmill blades!

Ah, I don't plan on displaying the time in such a "traditional"
format. :> I don't want folks to recognize it as a timepiece
unless they *know* how to "read" it. Instead, it will just
look like a kinematic sculpture...
But this project is way off in the distance. I have many other things
to do first.

<grin> Yup. In my case, the problem is figuring out what
*will* work "on paper" before investing lots of time building
something that just turns out to be a nonfunctional eyesore.
 
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