A Peek into the Future?

[MikeModified]

Alan has been updating his website https://www.retrotronics.org/

Under the "Projects" dropdown -> "IBM PC Jr related" are "jr-IDE", "SuperCART", and "ZM56 Modification". The first leads where one would expect, while the last two lead to "under construction" pages.

However, after scrolling down the jr-IDE page, the last entry in the left-hand column is "Related Projects" with two tabs:

1) "PC JR Super Cartridge" - "Cartridge replacement board that allows up to 512 KB of cartridge ROM images in a single slot fully select-able via DIP switches. It also allows you to replace your system BIOS with an image contained in the Super Cartridge" and

2) "PC Jr ZM56 ROM" - "Instruction on how to modify your PC Jr main board in various ways to allow for Upper Memory Blocks to be added on side-cars in the 'D' and 'E' segments as well as a very experimental modification to allow 128 KB independent CGA video RAM from 640 main memory."

Both of these have "Read More +" buttons that lead to no more info.

Both of the undated "Under construction" pages say "Pardon our Mess" "This page is still pending a brain dump. I will get to documenting this project soon. If this notice remains up here for more than a few weeks, hit me up via the contact form. Thanks."

Have those notices been up for more that a few weeks, Alan?

Mike

[alanh]

Yes.. sadly there just isn't that many hours in the day.

The ZM56 mod is detailed in a thread on this forum.

The super cart was a one off thing. It allowed placing 14 32K ROM images on one cart + a replacement system BIOS and selecting via DIP switches. There are better ways of running all of the past cartridges on demand however.

I do really need to add content to all my projects in the works.

[Shaos]

Where can I read more details about "Super Cart"? Does it have PCB layouts available for replication?...

P.S. In older thread I found this: https://www.retrotronics.org/svn/jride/trunk/supercart/
Is it most latest version?

[alanh]

That's it. I haven't worked on it since. Sorry. RL commitments.

[Shaos]

That's it. I haven't worked on it since. Sorry. RL commitments.

Thanks!

[alanh]

The only issue I am aware of from that design is one row of dip pin tails lined up with a plastic ridge inside of my ROM BASIC cartridge case and did not close all the way. I needed to be shifted down slightly or a new case 3D printed. It works just fine plugged in w/o a case.

Also, it should be possible to use a cheaper more available 22v10 instead of the atf750, but I haven't verified it. It's all combinatorial logic and the 22v10 has more LUT terms so it should fit just fine.

-Alan

[Shaos]

ok, I have 22v10 (and don't have ATF : ) so I believe I can modify your design

[alanh]

OK. At the same link above, I changed the device to 22v10 and created a jed file for programming. Most EEPROM programmers will write SPLDs like 22v10s and 16v8s. And FYI the 22v10 and 750 share common pinouts so you don't need to modify the board. Just order it through OSHPark or similar service. The ATF750 is an 'enhanced' cousin of the 22v10. It has an extra flip-flop per output (for feedback) and support independent sync preset, async reset, and clocks per flip-flop. Doesn't have as many product terms going into the LUTs however. But a nice part.

[Shaos]

Cool, thanks!

[OldComputerGuy]

Are any of the hardware projects available fully assembled? Some of us don't have the ability to make them ourselves.