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Blast from the past... Z80!

T

Tim Williams

Jan 1, 1970
0
I put together a Z80 microcomputer the other day. Real simple:
processor, clock oscillator, NVRAM holding program and data, pair of
74LS138s for memory and I/O decoding, and two 74LS273 latches for
output. And a forest of jumper wires. Right now I have it scrolling
a message across four matrixed digits of seven-segment display. Seven
segments make really ugly Latin characters though. :-(

Youtubification:

Tim
 
D

David L. Jones

Jan 1, 1970
0
I put together a Z80 microcomputer the other day. Real simple:
processor, clock oscillator, NVRAM holding program and data, pair of
74LS138s for memory and I/O decoding, and two 74LS273 latches for
output. And a forest of jumper wires. Right now I have it scrolling
a message across four matrixed digits of seven-segment display. Seven
segments make really ugly Latin characters though. :-(

Youtubification:

Tim

"Zee" 80?
Must be one of those wimpy copies of a real "Zed" 80 :p

Nice fun stuff BTW, sham it won't last long on that breadboard.

Dave.
 
I put together a Z80 microcomputer the other day. Real simple:
processor, clock oscillator, NVRAM holding program and data, pair of
74LS138s for memory and I/O decoding, and two 74LS273 latches for
output. And a forest of jumper wires. Right now I have it scrolling
a message across four matrixed digits of seven-segment display. Seven
segments make really ugly Latin characters though. :-(

Youtubification:

Tim

Nice, I just picked up a Kaypro for free. When I get around to it I'll
power it up.
A nice display for your project would be one of those serial driven
40x4 matrix VFDs.
http://www.noritake-elec.com/uversion.htm
 
J

James Arthur

Jan 1, 1970
0
Tim said:
I put together a Z80 microcomputer the other day. Real simple:
processor, clock oscillator, NVRAM holding program and data, pair of
74LS138s for memory and I/O decoding, and two 74LS273 latches for
output. And a forest of jumper wires. Right now I have it scrolling
a message across four matrixed digits of seven-segment display. Seven
segments make really ugly Latin characters though. :-(

Youtubification:

Tim

Tim, you're a beast!

Now you need to make it use a Windows PC. You know, as its
slave--a peripheral. As a keyboard interface, maybe?

Cheers,
James Arthur
 
I

ItsASecretDummy

Jan 1, 1970
0
Nice, I just picked up a Kaypro for free. When I get around to it I'll
power it up.
A nice display for your project would be one of those serial driven
40x4 matrix VFDs.
http://www.noritake-elec.com/uversion.htm


Mame emulator emulates the Z80 and about 35 other processors.

The source code is a great learning tool for programmers, and kids too.
 
T

TTman

Jan 1, 1970
0
Tim Williams said:
I put together a Z80 microcomputer the other day. Real simple:
processor, clock oscillator, NVRAM holding program and data, pair of
74LS138s for memory and I/O decoding, and two 74LS273 latches for
output. And a forest of jumper wires. Right now I have it scrolling
a message across four matrixed digits of seven-segment display. Seven
segments make really ugly Latin characters though. :-(

Youtubification:

Tim
Bet I had the most innovative use of a Z80 back in the 80s It was a //
printer buffer that could do auto landscape /portrait flip...The innovative
bit was the memory.... 8x64K dram chips hung directly on the address bus
with /ras/cas driven by I/O control lines. Memory access was I/O
mapped(effectively) and something like 10 instrucions per byte to access.
Happy days :)
 
S

StickThatInYourPipeAndSmokeIt

Jan 1, 1970
0
Bet I had the most innovative use of a Z80 back in the 80s


Nope. That would be "Upright Video Arcade Games", and it made $5B a
year, chucko.
 
A

Archimedes' Lever

Jan 1, 1970
0
Interesting, what do the numbers mean?


Are you joking? It was putting up letters. It said hello, etc. Look
again.
 
M

MooseFET

Jan 1, 1970
0
Some of those ghastly old CPU architectures - Z80, 8051 - are
reappearing as free FPGA soft cores.

I like the Z80 and 8051. They are very nice processors.
Is the CDP1802 available as a free core? Now there's a nasty
processor if there ever was one.
Just when you thought it was safe...

The Spartan6 should be out soon, and some are rumored to include a
hard-core ARM processor. Pricing should be interesting.

I refuse to design it in so the rest of you are safe.

For those who don't remember: I have a 100% hit rate on every CPLD or
other FPGA like part I design in going out of production. So as a
service to others I have decided never to design in a device like that
from a company that I wish to have remain in business.
 
M

Michael

Jan 1, 1970
0
Tim said:
I put together a Z80 microcomputer the other day. Real simple:
processor, clock oscillator, NVRAM holding program and data, pair of
74LS138s for memory and I/O decoding, and two 74LS273 latches for
output. And a forest of jumper wires. Right now I have it scrolling
a message across four matrixed digits of seven-segment display. Seven
segments make really ugly Latin characters though. :-(

Youtubification:

Tim

Ah, the venerable Z80. I have a handful of them and their various peripheral chips. e.g. DMA. My
first uC project was an EPROM burner made with 2MHz (raw power!) Z80. I still have it but haven't
used it in years because ..... well, I haven't had to burn an EPROM! EEPROM is so much nicer to
work with.
 
K

krw

Jan 1, 1970
0
I wouldn't use an 8051 when more modern architectures are around. The
advantage of having the cpu in the fpga is that you get a lot of speed
and save a lot of pins.

Yep. I'd kinda like a DSP in there though. It seems a waste of
high speed logic to do the function our DSP is now doing (and it
works), but saving pins would be a big bonus.
We've been considering going to a new Coldfire processor, with all
sorts of chip selects, dram controllers, timers, stuff like that. But
if we get an FPGA with an ARM inside, the peripherials all just become
adaptable chunks of FPGA, so if we want 17 timers, we get 17 timers.
Or maybe a cpu with 231 parallel port pins.


Yup, the fpgas are great for brute parallel processing. But they're
also great when you just need a lot of counters and latches and port
pins, quantities of dumb stuff.

Yep. Our current design is a mess of SPI and I2C stuff that could
easily be swept into a small FPGA. FPGAs (and CPLDs) are cheap now
too. Hardly any reason for small junk and glue logic anymore. The
new PSoC stuff from Cypress looks interesting too.
 
K

krw

Jan 1, 1970
0
Nobody makes a 100-channel DAC, but it's not hard to put 100
delta-sigma DACs into a small FPGA. I think you could make a decent
ADC, too; most lvds inputs are actully good comparators.

Interesting idea. We have a dozenish audio channels, using six
Burr Brown TLV320s. It sure would save a pile of grief to sweep
those under the rug too. The Cypress chips look like they'd sweep
in a whole log of the external analogs up to the howland pumps and
hybrids.
FPGAs pipeline design a lot, too. You don't have to design the logic
until the PC board is out for fab and assembly. And changes take
hours, no board spins, no red jumper wires.

Absolutely. Not to mention features in flash.
It's really liberating to have 100,000 gates laying around at an
incremental use cost of zero.

Can help with testing too. FPGAs are fun.
 
K

krw

Jan 1, 1970
0
No wonder you hate programming.
You simply never programmed a good processor.

The Z80 is a very very very nice processor to work with.

If you enjoy moving data from here to there and back. I'm with
John. Yuck.
 
K

krw

Jan 1, 1970
0
PSoC has been around for awhile, although Cypress occasionally re-targets it
to different markets... such as their current push into using it for touch
sensors.

The *NEW* stuff (PSoC-III, IIRC) looks like it'll finally be
useful, is my point.
The analog bits are pretty cool. The CPU they include is a rather ugly,
low-performance no-frills design. But hey, it does get the job done, I
suppose...

Have CPU. Planning on adding FPGA. A PSoC-III looks like it'll
make the design almost entirely programmable. ;-)
 
R

Rich Grise

Jan 1, 1970
0
No wonder you hate programming.
You simply never programmed a good processor.

The Z80 is a very very very nice processor to work with.

Hear, Hear! I also enjoyed working with the 6502. The 8051 isn't bad when
you get used to its foibles and learn how to use the timer. ;-)

But the first time I worked with the 68HC11 I fell in love with
its timer system. :)

Cheers!
Rich
 
N

Nico Coesel

Jan 1, 1970
0
John Larkin said:
Some of those ghastly old CPU architectures - Z80, 8051 - are
reappearing as free FPGA soft cores.

Just when you thought it was safe...

The Spartan6 should be out soon, and some are rumored to include a
hard-core ARM processor. Pricing should be interesting.

Now that is going to kick some ass! A sales rep already mentioned an
ARM core in a Xilinx device.
 
K

krw

Jan 1, 1970
0
Ah, gotcha. I did a bit of Googling, and apparently there is some PSOC 3
hardware out (if you know the right people) but software is still being
developed and hasn't been released yet? I'll have to keep on top of it.

The Cypress rep was here last week with the Avenet rep, doing their
dog and pony thing. They said there was hardware available, though
samples and software wouldn't really be available in the spring. I
said I wanted to be on their list when I could actually play with
the software. Maybe April.
 
K

krw

Jan 1, 1970
0
Sorry I do not get that.
Would you care to elaborate on 'moving data from here to there'?

95% of the instructions are moves (load/store register).
 
K

krw

Jan 1, 1970
0
Yeah, sort of a kluged 8008.

A lot better than an 8008. A little bit better than an 8080/5. In
that vintage I liked the NSC PACE better.
 
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