Topics

1861 Replacement


joshbensadon
 

Of course not.  Please feel free to do so.  I am so busy these days.


From: cosmacelf@groups.io <cosmacelf@groups.io> on behalf of COSTAS SKORDIS <conneth@...>
Sent: Wednesday, September 16, 2020 1:19 PM
To: cosmacelf@groups.io <cosmacelf@groups.io>
Subject: Re: [cosmacelf] 1861 Replacement
 
Do you mind if I try?

On Sep 16, 2020, at 10:44 AM, joshbensadon <jbensadon@...> wrote:


Sorry, never did this in Kicad


From: cosmacelf@groups.io <cosmacelf@groups.io> on behalf of COSTAS SKORDIS <conneth@...>
Sent: Wednesday, September 16, 2020 11:01:40 AM
To: cosmacelf@groups.io <cosmacelf@groups.io>
Subject: Re: [cosmacelf] 1861 Replacement
 
Josh,

Are there any KiCad files for the schematic?

Costas Skordis
Austin, Texas

On Sep 15, 2020, at 12:24 PM, joshbensadon <jbensadon@...> wrote:


*Great!*!*!!  After your wife kills you, she'll put it up on Ebay and the cycle starts all over again!

How about building the VELF?  I think the schematics and firmware is in my folder somewhere....

Cheers,
Josh Bensadon
Toronto




From: cosmacelf@groups.io <cosmacelf@groups.io> on behalf of COSTAS SKORDIS <conneth@...>
Sent: Tuesday, September 15, 2020 1:00 PM
To: cosmacelf@groups.io <cosmacelf@groups.io>
Subject: Re: [cosmacelf] 1861 Replacement
 

It was pricey and my wife is going to kill me but I bought the 1802 and 1861 all for $105 including tax

 

From: cosmacelf@groups.io <cosmacelf@groups.io> On Behalf Of P Todd Decker via groups.io
Sent: Tuesday, September 15, 2020 9:31 AM
To: cosmacelf@groups.io
Subject: Re: [cosmacelf] 1861 Replacement

 

FYI -- There is an RCA COSMAC 1861 being offered on eBay from a domestic seller for $70 plus $4.80 shipping:  https://www.ebay.com/itm/184448193087?ul_noapp=true


joshbensadon
 

Will,   LoL,  and Murphy's law strikes again!



From: cosmacelf@groups.io <cosmacelf@groups.io> on behalf of wrcooke@... <wrcooke@...>
Sent: Wednesday, September 16, 2020 2:21 PM
To: cosmacelf@groups.io <cosmacelf@groups.io>
Subject: Re: [cosmacelf] 1861 Replacement
 
Wrapping is fine.  It's when you find the wire that is the bottom of three wraps needs to move to another pin with three wraps that my blood pressure sky rockets.

Will

On 09/16/2020 1:12 PM COSTAS SKORDIS <conneth@...> wrote:


Todd,

You should try wire wrapping, it’s so relaxing.

Costas Skordis
Austin, Texas

On Sep 16, 2020, at 1:09 PM, P Todd Decker via groups.io <ptdecker@...> wrote:

Oh I so need to learn wire wrap 

---
P. Todd Decker
913-284-8814

On Sep 16, 2020, at 12:24 PM, COSTAS SKORDIS <conneth@...> wrote:

Thanks Lee but I have one already that I built a few years  back.

Regards 

Costas Skordis
Austin Texas
<image0.jpeg>
<image1.jpeg>

On Sep 16, 2020, at 10:41 AM, Lee Hart <leeahart@...> wrote:

From: COSTAS SKORDIS <conneth@...>
Josh,

Are there any KiCad files for the schematic?

Josh can answer that one. But another possibility for your vintage 1802 and 1861 might to build an original ELF from the PE articles. Josh and Chuck Yaykm and I and did one for the VCFMW show a couple years ago, and provided updated parts lists and sources, schematics, and layout. The plans for it are here:

<https://apc01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.sunrise-ev.com%2Fvcf-elf.htm&amp;data=02%7C01%7C%7Cb0e8942489304fc96de208d85a5703a0%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637358677051723274&amp;sdata=qSi2kZE1Pzku7%2B8sXXdN4CeP4tBfCfdUZEG2IqBbnV8%3D&amp;reserved=0>

Lee Hart


--
Excellence does not require perfection. -- Henry James
--
Lee A. Hart https://apc01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.sunrise-ev.com%2F&amp;data=02%7C01%7C%7Cb0e8942489304fc96de208d85a5703a0%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637358677051723274&amp;sdata=o8qD%2F3uZqCBlePlx2B%2BM5GCDWTLF1T4paPOM9q%2FtpOU%3D&amp;reserved=0






"A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away." --  Antoine de Saint-Exupery

"The names of global variables should start with    // "  -- https://isocpp.org



P Todd Decker
 

Lee — do you happen to remember that later issue? I have downloaded PDFs of the part one and two for the original article. I’d like to get that next one if you remember it

---
P. Todd Decker
913-284-8814

On Sep 16, 2020, at 1:21 PM, Lee Hart <leeahart@...> wrote:

From: "P Todd Decker via groups.io"
Oh I so need to learn wire wrap

Yep; that's how it was done. :-)

Lest you fear the time and effort it would take, we had visitors to our table at VCFMW *build an Elf from scratch* using wire-wrap. Each visitor added a wire or two. Most had never wire-wrapped before in their lives. Yet by the end of the show, we had darned near finished wiring it!

With regards to the 1861, a later PE article added it to the Elf, with only a few changes to the layout. With wire-wrap, such changes are easy to make.

Lee


--
Excellence does not require perfection. -- Henry James
--
Lee A. Hart http://www.sunrise-ev.com


COSTAS SKORDIS
 

Thank you.

Once I have created it I will make it available to the group, especially for review!

Regards,


Costas Skordis


On Sep 16, 2020, at 13:28, joshbensadon <jbensadon@...> wrote:


Of course not.  Please feel free to do so.  I am so busy these days.


From: cosmacelf@groups.io <cosmacelf@groups.io> on behalf of COSTAS SKORDIS <conneth@...>
Sent: Wednesday, September 16, 2020 1:19 PM
To: cosmacelf@groups.io <cosmacelf@groups.io>
Subject: Re: [cosmacelf] 1861 Replacement
 
Do you mind if I try?

On Sep 16, 2020, at 10:44 AM, joshbensadon <jbensadon@...> wrote:


Sorry, never did this in Kicad


From: cosmacelf@groups.io <cosmacelf@groups.io> on behalf of COSTAS SKORDIS <conneth@...>
Sent: Wednesday, September 16, 2020 11:01:40 AM
To: cosmacelf@groups.io <cosmacelf@groups.io>
Subject: Re: [cosmacelf] 1861 Replacement
 
Josh,

Are there any KiCad files for the schematic?

Costas Skordis
Austin, Texas

On Sep 15, 2020, at 12:24 PM, joshbensadon <jbensadon@...> wrote:


*Great!*!*!!  After your wife kills you, she'll put it up on Ebay and the cycle starts all over again!

How about building the VELF?  I think the schematics and firmware is in my folder somewhere....

Cheers,
Josh Bensadon
Toronto




From: cosmacelf@groups.io <cosmacelf@groups.io> on behalf of COSTAS SKORDIS <conneth@...>
Sent: Tuesday, September 15, 2020 1:00 PM
To: cosmacelf@groups.io <cosmacelf@groups.io>
Subject: Re: [cosmacelf] 1861 Replacement
 

It was pricey and my wife is going to kill me but I bought the 1802 and 1861 all for $105 including tax

 

From: cosmacelf@groups.io <cosmacelf@groups.io> On Behalf Of P Todd Decker via groups.io
Sent: Tuesday, September 15, 2020 9:31 AM
To: cosmacelf@groups.io
Subject: Re: [cosmacelf] 1861 Replacement

 

FYI -- There is an RCA COSMAC 1861 being offered on eBay from a domestic seller for $70 plus $4.80 shipping:  https://www.ebay.com/itm/184448193087?ul_noapp=true


gregory simmons
 

If I can jump in here, I think it was July, 1977, page 41:  https://worldradiohistory.com/Archive-Poptronics/70s/1977/Poptronics-1977-07.pdf

greg AB8IM

On Wednesday, September 16, 2020, 03:28:29 PM EDT, P Todd Decker via groups.io <ptdecker@...> wrote:


Lee — do you happen to remember that later issue?  I have downloaded PDFs of the part one and two for the original article.  I’d like to get that next one if you remember it

---
P. Todd Decker
913-284-8814

On Sep 16, 2020, at 1:21 PM, Lee Hart <leeahart@...> wrote:

From: "P Todd Decker via groups.io"
> Oh I so need to learn wire wrap


Yep; that's how it was done. :-)

Lest you fear the time and effort it would take, we had visitors to our table at VCFMW *build an Elf from scratch* using wire-wrap. Each visitor added a wire or two. Most had never wire-wrapped before in their lives. Yet by the end of the show, we had darned near finished wiring it!

With regards to the 1861, a later PE article added it to the Elf, with only a few changes to the layout. With wire-wrap, such changes are easy to make.

Lee


--
Excellence does not require perfection. -- Henry James
--
Lee A. Hart http://www.sunrise-ev.com










David Schultz
 

On 9/16/20 2:28 PM, P Todd Decker via groups.io wrote:
Lee — do you happen to remember that later issue? I have downloaded PDFs of the part one and two for the original article. I’d like to get that next one if you remember it
http://billr.incolor.com/elf/html/elf-4-41.htm



--
http://davesrocketworks.com
David Schultz


Lee Hart
 

P Todd Decker wrote:
Lee — do you happen to remember that later issue?
gregory simmons wrote:
If I can jump in here, I think it was July, 1977, page 41:
https://worldradiohistory.com/Archive-Poptronics/70s/1977/Poptronics-1977-07.pdf
That's the one! You beat me to it. :-)

Lee

--
A designer knows he has achieved perfection not when there is
nothing left to add, but when there is nothing left to take away.
-- Antoine de Saint Exupery
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com


the-eagle@att.net
 

Here is the complete article that I know of, all 4 parts in one PDF file.

 

Regards,

Chuck

 


P Todd Decker
 

Wonderful!

---
P. Todd Decker
913-284-8814

On Sep 16, 2020, at 8:58 PM, the-eagle@... <The-Eagle@...> wrote:

Here is the complete article that I know of, all 4 parts in one PDF file.

 

Regards,
Chuck

 

<PopularElecwebc.pdf>


cmdrcosmac
 


 Just wanted to say thay I've built Chuck Yakym's Rev. E 1861 replacement and it works beautifully!
I used 74HC-series logic and a 28C256 EEPROM for the timing ROM. There is no image jitter.

 I entered the program in the Pop'Tronics article into the MicroDOS editor, assembled and CDSBIN'ed
it and found an issue worth noting. The code in the Pop'Tronics article does not enable
interrupts, so if the program is started under UT71 or under MicroDOS as a .CM app the interrupt
code doesn't run and the display is hash. After Reset,Go the starship is shown.
So I added RET DC000H to the beginning of the code, reassembled it and now it works as a .CM file.

 I would recommend this circuit for an expansion board for the other Elf designs out there. No hard
to get parts, no GAL's to program, and a "just works" design. A "Thank you" to Chuck Yakym.

-Chuck


the-eagle@att.net
 

Chuck,

 

            I have attached the 1861 animation program that I wrote to test the 1861 replacement circuit. It demonstrates all 3 video resolutions that the 1861 uses.

 

Regards,

Chuck Yakym


the-eagle@att.net
 

It appears that the group didn't allow my last attached files, so I am trying once again. Hopefully these file come thru now.

Regards,
Chuck Yakym


cmdrcosmac
 

Chuck,
 Thanks much for the demo program! I converted the source listing to RCA's AS8
format, assembled and ran it under MicroDOS. It works excellently.
-Chuck


the-eagle@att.net
 


Chuck,
          I have found a "Readme.txt" file that I wrote a day after I wrote the 1861 animation program. This file will tell you how to define and/or use the undefined user commands. Please remember that this file is based on the original program being ORG"ed" at 3000 hex. If you change the ORG of the original program then the addresses within this text file should be offset to reflect the new ORG"ed" addresses used. Enjoy.

Regards
Chuck Yakym


cmdrcosmac
 

After building Chuck Yakym's Rev. E 1861 replacement I got to thinking...
(Dangerous, I know.)

 Could the horizontal resolution be doubled?
The idea is to double the CPU clock and double the shift register clock.
The timing ROM would need to be modded so as to keep the CSYNC timing the same
as the original, and the rest of the timings changed to accommodate 16, rather
than 8 DMA cycles per line, giving 128 pixels per line.

 This would double the CPU throughput, so game timing loops would need to be changed,
mostly by doubling (or halving) any timing constants affecting gameplay.
 The size of the screen RAM buffers would double.

A possible limiting factor is the access time of the timing ROM. EEPROMs are convenient
to use, and my build uses a 28c256 at 150 ns. with standard PIXIE timing.
 I don't have a good enough scope to read the timings, but as UT71 can run
in the same type EEPROM at 4.9MHz, so the 150 ns. device might do. if not, the next
practical step might be a one time programmable 27c device. These are made up to 512kX8
and speeds down to 45 ns.

 As the PIXIE is usually turned on by an OUT or IN 1 instruction, perhaps the content of
an OUT 1 instruction could select which of 2 timing ROMs (or address spaces in one
512kX8 device) is active, so as to preserve backward compatibility.

 Another possibility is to change the CSYNC timing to use a VGA monitor because NTSC
yellow-jack inputs on monitors are getting scarce.

 Does this sound reasonable.. or harebrained?

-Chuck


Peter Renaud
 

This the rev B output on a mini tv I picked up on Aliexpress. So there are still some composite video monitors still available. 



Image.jpeg


From: cosmacelf@groups.io <cosmacelf@groups.io> on behalf of cmdrcosmac <cmeyer@...>
Sent: Tuesday, October 27, 2020 7:20:04 PM
To: cosmacelf@groups.io <cosmacelf@groups.io>
Subject: Re: [cosmacelf] 1861 Replacement
 
After building Chuck Yakym's Rev. E 1861 replacement I got to thinking...
(Dangerous, I know.)

 Could the horizontal resolution be doubled?
The idea is to double the CPU clock and double the shift register clock.
The timing ROM would need to be modded so as to keep the CSYNC timing the same
as the original, and the rest of the timings changed to accommodate 16, rather
than 8 DMA cycles per line, giving 128 pixels per line.

 This would double the CPU throughput, so game timing loops would need to be changed,
mostly by doubling (or halving) any timing constants affecting gameplay.
 The size of the screen RAM buffers would double.

A possible limiting factor is the access time of the timing ROM. EEPROMs are convenient
to use, and my build uses a 28c256 at 150 ns. with standard PIXIE timing.
 I don't have a good enough scope to read the timings, but as UT71 can run
in the same type EEPROM at 4.9MHz, so the 150 ns. device might do. if not, the next
practical step might be a one time programmable 27c device. These are made up to 512kX8
and speeds down to 45 ns.

 As the PIXIE is usually turned on by an OUT or IN 1 instruction, perhaps the content of
an OUT 1 instruction could select which of 2 timing ROMs (or address spaces in one
512kX8 device) is active, so as to preserve backward compatibility.

 Another possibility is to change the CSYNC timing to use a VGA monitor because NTSC
yellow-jack inputs on monitors are getting scarce.

 Does this sound reasonable.. or harebrained?

-Chuck


Lee Hart
 

cmdrcosmac wrote:
After building Chuck Yakym's Rev. E 1861 replacement I got to thinking...
Could the horizontal resolution be doubled?
Yes! My VIP2K does exactly this to triple the horizontal resolution. I raised the 1802 clock to 4 MHz, then programmed the EPROM for 32 (instead of 14) bytes per horizontal scan line. 24 (instead of 8) of those bytes are displayed via DMA.

Lee Hart

--
A designer knows he has achieved perfection not when there is
nothing left to add, but when there is nothing left to take away.
-- Antoine de Saint Exupery
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com


cmdrcosmac
 

Peter,
Very similar to what I have. Mine was a Dumpster score. It was made in the days when
analog video was on the way out and has RF, S-Video, composite yellow jack, component,
VGA, HDMI. Guess the designer didn't know which way the cat was gonna jump and wanted
to cover all his bases. I also have a more recent 32" cheapie with only HDMI inputs.
 While component inputs aren't extinct now, I do think VGA will outlive it, though
maybe not for long. Product lifecycles are getting shorter now. Adapting Chuck Yakym's
design to VGA may postpone the day it will be difficult to find a monitor for an Elf.

 another note- Some of these early small LCD tv's (many but not only Emerson) had a nasty
design bug. If the set was operating and the power plug pulled or powered down with the
switch on a power strip, next time you turned it on the thing would come up in "burn-in"
mode- cycling thru red, green, blue screen. The only to get it working was to use the remote
to send it a secret sequence on the buttons. So always shut it off with the power button.

Best,
Chuck