A replacement 64K memory and display expansion module for the IBM PCjr.
Files
pcjr-64k-display.xls
Bill of Materials (BoM) - This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. CC-BY-NC 4.0, Copyright (C) 2020, David Anders. All Rights Reserved.
PDF Schematic - This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. CC-BY-NC 4.0, Copyright (C) 2020, David Anders. All Rights Reserved.
Adobe Portable Document Format -
23.95 kB -
06/21/2020 at 21:29
Eagle CAD Design Files - This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. CC-BY-NC 4.0, Copyright (C) 2020, David Anders. All Rights Reserved
Gerber PCB Files - This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. CC-BY-NC 4.0, Copyright (C) 2020, David Anders. All Rights Reserved
i've added a Bill of Materials to the files list as well as a datasheet for the 64k x 4bit DRAM used on the project. if you have any questions feel free to give me a shout! side note, i have plenty of the parts in stock, so i could make a "parts kit" for you and sell it via ebay if you are interested!
i generally don't post log entries these days as they don't garner much feedback and consume a lot of time to do properly. The IBM PCjr has an internal memory expansion slot intended to add 64K of memory that can be shared for system resources as well as serve as resource for the equivalent of a CGA (Color Graphics Array). simply plug in the card into the memory slot and you are done!
OK, fair, but I'm missing something. Does this genuinely *replace* a display controller (MGA, which does not 'do' graphics, as well as CGA/EGA/VGA/PGC/etc which do), or just augment its memory abilities...?
If it *does* replace the display controller, then how does it generate and control the screen?
If not, perhaps a better name for it would be "64k Dual Mode System/Display RAM Expansion Card" or the like.
Also: forgive me, the PCjr is one of a few older boxes I've neglected my education on. I'm mostly a Commodore and MS-DOS kinda guy ;)
This is simply a 64K memory upgrade. the memory is shared between the system resources and the display controller. this just gives the CGA controller more memory to work with for additional screen/color modes. the name is a duplicate of the original name of the board as it was sold by IBM...
where i can get part list?