Date   
Re: new "membership card" format computer in this month's Nuts and Volts

Lee Hart
 

ajparent1/kb1gmx wrote:
If its running CP/M then its not the version shown at the web
site (nutsandvolts). There is at best not enough ram and the
EEprom is in the space where ram is nominally required.

The Altaid at www.sunrise-ev.com <http://www.sunrise-ev.com> however
provides the memory maps and ram needed so yes it can and does.
Yes indeed. :-) Despite the small size, it has bank switching and supports up to 512K of RAM and ROM.

It would not take much to build a version of the NutsandVolts
version with 8085 with adequate ram to run CP/M. Using
similar techniques as the 8080 version or adding the logic
to start at F000H with rom there then a 48K system is set
to go.
Yes. It would also need something to simulate disk drives (a big RAM or SD-card). Though you would be hard pressed to get it on an Altoids-size card.

Been hacking eight bit CP/M since V1.3 on 8080, 8085, Z80, Z180,
Z280 and NSC800.
An impressive history!

THE 1802 runs something that's harder to understand at the
source code level but the result is a far better OS. Mike Riley's
ELFOS (I have it on a EELF2000).
Experience is a wonderful teacher. CP/M is kind of the Ford model T of microcomputer operating systems. Very simple, but also very effective. It was enough to get the job done, and showed everyone what was possible. They learned, and went on to create better and better OS.

We owe a tremendous debt of gratitude to the early microcomputer pioneers. They built computers and wrote code that the big computer companies said was "impossible". Then they shared their work, so others could learn from it and improve it!

--
I have no special talents. I am only passionately curious.
-- Albert Einstein
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

Re: new "membership card" format computer in this month's Nuts and Volts

ajparent1/kb1gmx
 

If its running CP/M then its not the version shown at the web
site (nutsandvolts).   There is at best not enough ram and the
EEprom is in the space where ram is nominally required.

The Altaid at  www.sunrise-ev.com however provides the
memory maps and ram needed so yes it can and does.

That is the big differences from one flavor to another.
It would not take much to build a version of the NutsandVolts
version with 8085 with adequate ram to run CP/M. Using
similar techniques as the 8080 version or adding the logic
to start at F000H with rom there then a 48K system is set
to go.

CP/M requires 16(20)k from 0000h to run that's a very minimal
system and most apps want at least 48K.  

Minimal CCP/BDOS/BIOS eats 6.5K and typically more.

Been hacking eight bit CP/M since V1.3 on 8080, 8085, Z80, Z180,
Z280 and NSC800.

THE 1802 runs something that's harder to understand at the
source code level but the result is a far better OS.  Mike Riley's
ELFOS (I have it on a EELF2000).

Allison

Re: new "membership card" format computer in this month's Nuts and Volts

Lee Hart
 

joshbensadon via Groups.Io wrote:
Lee,

You're missing out on telling the best part of the ALTAID 8800, which is
that it runs CP/M
Good point. It didn't occur to mention it on the cosmacelf list, as the Elf doesn't run CP/M, either. But if they go to the website, it *does* mention that CP/M is running. :-)

Lee Hart

--
I have no special talents. I am only passionately curious.
-- Albert Einstein
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

Re: new "membership card" format computer in this month's Nuts and Volts

joshbensadon
 

Lee,

You're missing out on telling the best part of the ALTAID 8800, which is that it runs CP/M

Cheers,
Josh



On Monday, September 2, 2019, 9:15:59 PM EDT, Lee Hart <leeahart@...> wrote:


gregory simmons via Groups.Io wrote:
> Looks almost familiar...
> https://www.nutsvolts.com/magazine/article/build-a-pocket-sized-altair-computer

Yes; *mighty* familiar! :-) I did an 8080 membership card a couple years
ago. I even called it the Altaid 8800. :-) You can see it here
<http://www.sunrise-ev.com/8080.htm>.

David Hunter did his own version. I guess he felt inspired. Looks like a
nice design. His uses the 8085 CPU, and sticks with 1980's vintage
thru-hole parts. Very much in the spirit of my membership cards. Looks
like he did a nice job on the software, too. Congratulations!

Lee Hart

--
I have no special talents. I am only passionately curious.
    -- Albert Einstein
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com



Re: DS275 substitute on Elf2k

Rob Carnegie
 

Yes, I will do so.

Re: DS275 substitute on Elf2k

Rob Carnegie
 

OK- I have order 2 DS275 for you from Aliexpress (I ordered 2 for myself as well)

I actually went a bit nuts on Aliexpress because I found a bunch of other scarce ICs as well.

Rob

Re: new "membership card" format computer in this month's Nuts and Volts

ajparent1/kb1gmx
 

I'm a long time (started with 8080 in 1974) 8085/z80 user so both are very familiar.

Its pretty slick.  Its close to the base Netronics Explorer-85 though a lot smaller.
I have one I built back in late '77 when it was first introduced.

I've done similar only using 32k Eeprom and 32K ram and about twice as large
for hand wired.  The 80085 is a fun part to use and far easier to use than 8080
with its odd clock and multiple voltages.  The availability of multiple interrupt
inputs and the SIN and SOUT makes for low chip count systems.

Its fun seeing how people apply older cpus with fewer parts than "in the day".

Also check out the low chip count designs from  Grant Searle.    http://searle.hostei.com/grant/

Though many of those are challenged by the minimal chip count 1802
based systems.  That and most eat a lot more power unless you can find
a CMOS Z80 (84c004) or 80C85.

Allison

Re: new "membership card" format computer in this month's Nuts and Volts

Lee Hart
 

gregory simmons via Groups.Io wrote:
Looks almost familiar...
https://www.nutsvolts.com/magazine/article/build-a-pocket-sized-altair-computer
Yes; *mighty* familiar! :-) I did an 8080 membership card a couple years ago. I even called it the Altaid 8800. :-) You can see it here <http://www.sunrise-ev.com/8080.htm>.

David Hunter did his own version. I guess he felt inspired. Looks like a nice design. His uses the 8085 CPU, and sticks with 1980's vintage thru-hole parts. Very much in the spirit of my membership cards. Looks like he did a nice job on the software, too. Congratulations!

Lee Hart

--
I have no special talents. I am only passionately curious.
-- Albert Einstein
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

Re: Microboard Products Available #ELF #microboards

somaspack
 

Chuck, thanks for the comments.

I do have a hand-wired prototype for a CompactFlash Microboard based on a number of sources including Mike Riley's design. It's partially functional and I'm writing the software routines and testing. I don't have an ETA on a PCB hence it not being mentioned elsewhere but it is my current focus.

Regards,

Scott

new "membership card" format computer in this month's Nuts and Volts

gregory simmons
 

Re: Another Home Brew Hexadecimal Display

Lee Hart
 

Mark Moulding wrote:
Actually, I made a sort-of replacement also, except that it doesn't have
the latch. However, it's made entirely with period-correct parts -
Russian old-stock - and it uses Numitron clones for the display. You
can see it here: https://www.ebay.com/itm/322372769842
I've got some, and they are cute and very retro. :-) I've been trying to think of a good "steampunk" application for them.

--
I have no special talents. I am only passionately curious.
-- Albert Einstein
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

Re: Another Home Brew Hexadecimal Display

Mark Moulding
 

Actually, I made a sort-of replacement also, except that it doesn't have the latch.  However, it's made entirely with period-correct parts - Russian old-stock - and it uses Numitron clones for the display.  You can see it here: https://www.ebay.com/itm/322372769842
~~

Mark Moulding

Re: Another Home Brew Hexadecimal Display

Jeff Truck
 

Chuck,

That's an interesting site - thank you for sharing.

Jeff

On Mon, Sep 2, 2019 at 1:51 PM cmdrcosmac <cmdrcosmac@...> wrote:
It's been done.
Go to http://www.paleotechnologist.net/?p=1386
-Chuck

Re: Another Home Brew Hexadecimal Display

cmdrcosmac
 

It's been done.
Go to http://www.paleotechnologist.net/?p=1386
-Chuck

Re: Another Home Brew Hexadecimal Display

Magnus Kesselmark
 

Came think of it right now. I am trying to build a Moog synthesizer clone (Concertmate MG-1) and needed some odd divider ICs for the polyphonics. Find them on eBay or somewhere, but they were more that an arm and a leg EACH.
However found them cloned in UK and this is where my head begin to spin (or just my brain??).
 
It could be possible to design a small PCB with decoder/latch/driver ICs and leds oriented like Jeff’s.
 
Enclosed a pic of my divider. From ‘bottom’, 14 (golden) pins that fit into the standard 14-pin DIL config – PCB or socket.
 
/Magnus
 

From: Jeff Truck
Sent: Monday, September 02, 2019 1:31 AM
Subject: [cosmacelf] Another Home Brew Hexadecimal Display
 
While six TIL311 displays or other suitable chip can do the job with more simplicity it doesn’t beat the fun one gets rigging up a home brew circuit like this.  Utilizing a transistor to switch the power and ground like this puts me in touch with something that I base my current job on - the computer. 
 
The 28C16 EEPROM doesn’t pump out many mA and the inverter doesn’t sink enough mA from the common cathodes so I read Forrest Mims book and hooked up some 2N2222 transistors to supply 28mA per segment (via 180 ohm resistors) to get a nice and bright display.  Lightened the load on the chips. 
 
These NKR163-B3 displays are rated up to 30mA per segment.
 
A 555 timer coupled to an CD74HCT163 4 bit counter paired to a CD74HC137 3 to 8 selector multiplexes the display and the address being supplied to the EEPROM.  74HC373’s latch the data and the tri-state output is managed by a 74HC08 AND fed from the 137.  
 
According to the power supply this entire circuit is pulling 80mA.  I don’t have the high order address hooked up but the proof of concept seems to be running well.  The power supply reads 120mA when 8888 is displayed. 
 
I’ll post a schematic soon.  It’s a bit chicken-scratch right now. 
 
Jeff
 
 
 
 
 
 

Virusfritt. www.avast.com

Re: Okay, let's get really crazy... #csdp #cds #cross-assembly #mcds

taf123
 

Hi again.

You're right of course, was just wondering if you had anything else in mind.

In the meantime, I found the FDC9229BT which does the data separator and write precomp function and directly supports the FDC765.

I also  found the FDC9266 , which is basically both of these combined. And conveniently for me,   a UK based eBay source. I'll probably go with the 9266.

Best regards
Todd

Re: Another Home Brew Hexadecimal Display

cmdrcosmac
 

Lee,

Digi-Key sells the MAX6818 key debouncer for $6.03 by the onesies.
It's a 20-pin SSOP surface mount. The mounting might be a pain but
it's probably the only way to fit the function in your form factor.
Perhaps a multilayer board with the sensitive traces under a ground
layer, and/or a buffer before the cable.
-Chuck

Re: Another Home Brew Hexadecimal Display

Lee Hart
 

the-eagle@... wrote:
I like a stroll down memory lane every once in a while, The Membership
Hex Front Panel Card, only had the stray capacitance when we tried to
use the expansion port of it with a cable attached to it. IF my memory
is serving me correctly about the stray actions of the buttons, however
It is a very great design.
Hi Chuck,

Yes, that's right. The key inputs use a 40106 hex schmitt trigger for debounce. It only has a small amount of hysteresis. The key traces are exposed on the top board, and are also routed to the 26-pin expansion connector. Capacitance between wires in the ribbon cable, or touching the traces on the PCB would falsely toggle the read/write and load/wait/clear/run modes.

It needs a schmitt trigger with more hysteresis and/or RC filtering on the key inputs. But there's no more room on the PCB!

So, I set it aside until that "aha" moment when we think of a better way to do it. :-)

--
Whether we or our politicians know it or not, Nature is party to all
our deals and decisions, and she has more votes, a longer memory,
and a sterner sense of justice than we do. -- Wendell Berry
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

Re: Microboard Products Available #ELF #microboards

cmdrcosmac
 

Beautiful!!!
If I didn't already have an Elf I would be all over this.
 An interesting addition would be a card with a IDE/Compact Flash interface as shown
on Mike Riley's site, and a full 64k of RAM.
 
http://www.elf-emulation.com/index.html

Then you should be able to run Elf/OS or, with a bit of software hacking, RCA's disk-
based development tools.
-Chuck

Re: Another Home Brew Hexadecimal Display

Jeff Truck
 

You are correct and I bought and built his system earlier this year.  I was a little disappointed in his full circuit because it displays three decimal digits and I wanted a hex display to be used in an 1802 system.  So the concepts are the same.  

I love his videos too.  His material is based largely on the book Digital Computer Electronics by Malvino and Brown.   I bought a copy a while ago and love it too.  

Jeff



On Sun, Sep 1, 2019 at 9:44 PM cmdrcosmac <cmdrcosmac@...> wrote:
This looks like something Ben Eater did with his breadboard computer.

See   https://www.youtube.com/watch?v=dLh1n2dErzE&list=PLowKtXNTBypGqImE405J2565dvjafglHU&index=34&t=0s

If you haven't seen his videos please do so. They are excellent.
-Chuck