I thought this should be of interest: I collected some links to designs using stacked chips - mostly DIP chips - to get high density or to expand an existing circuit board with minimal work.

Richard Goedeken wanted to switch kernal ROMs in his Plus 4
http://www.fascinationsoftware.com/FS/h ... witch.html


Duane Elscott made 4 towers of 16 SRAMs for a wirewrapped graphics board. From
http://web.archive.org/web/200406112215 ... tt/mem.htm
"If you're wondering why one of the stacks in the picture is taller than the rest, those were a different brand of ICs, with a slightly thicker body."


Timo Noko stacked 35 DRAMs to provide tagged lisp node storage in an Osborne luggable.
http://anycpu.org/forum/viewtopic.php?t=235&p=1456


Garth Wilson stacks four 512Kx8 SRAMs on a DIP header to get 2Mx8, with a 74AC139 stood on edge at the end to select the right chip.
viewtopic.php?p=7564#p7564


Garth Wilson's stack of 8 chips with a side order of decoder
viewtopic.php?f=4&t=2322&start=30


(More from Garth on this page)

Duane Degn stacks 8 serial chips to make a byte serial memory
http://forums.parallax.com/discussion/1 ... it-version


Quinn Dunki's Veronica machine piggybacks two RAMs
http://quinndunki.com/blondihacks/?p=1322


IBM's own 64k memory expansion for the 5150 PC used stacked chips.
http://www.minuszerodegrees.net/5150/ea ... _early.htm


And again: this pair of 64Kbit, plastic-packaged DRAMs in DIPs have been stacked and soldered together at the Texas Instruments factory to produce a 128Kbit device with a small footprint. This product is destined for a socket in an IBM PC/AT clone that had broken the 640K barrier"
https://eda360insider.wordpress.com/201 ... packaging/


Stacked chips in John Draper’s 24k Apple II, from "Captain Crunch’s Memory Modification" at
http://www.willegal.net/blog/?p=7246


Ronald Dekker stacks EPROM and SRAM in his "tiny but powerful stand alone BASIC microcomputer, not larger than the size of a package of cigarettes built entirely from salvaged components, just for fun!"
See
http://www.dos4ever.com/8031board/8031board.html


"This early 1980s “advanced” calculator board included dual in-line packages (DIPs) stacked on top of each other."
http://electronicdesign.com/embedded/pa ... rospective


Dave Curran discovered this stacked rom version switcher when refurbishing a ZX80
http://blog.tynemouthsoftware.co.uk/201 ... epair.html


[Previously posted on G+]

Wow! -- some great work there. The byte serial memory is especially clever. And the 35-bit DRAM... Well!

I myself have often stacked chips, usually in unremarkable (though highly expedient) ways. But the photos below show a slight departure from the norm.

What we see is a Z80 SBC that features an 'hc574 used as an 8-bit output port. But because it was sometimes necessary to update fewer than all 8 bits there was a need to know what the existing data was. At first I managed that by maintaining a duplicate copy of the port's contents in RAM -- a workable but slightly cumbersome solution. It'd be better if the port itself could be read back...

Readback capability took the form of an 'hc245 soldered on top of the '574. As you can see, it was necessary to stagger the pins to make the appropriate connections line up!

-- Jeff

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In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html

Yuh got all the angles covered.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

Reminds me of a public housing project for some reason.

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x86?  We ain't got no x86.  We don't NEED no stinking x86!

Nice. Seems like he embedded his own linear accelerator in there as well. Maybe he salvaged it from one of the Ghostbusters back packs.

Those photos are eerily creepy. Like photos of insects.

Those are some fine examples of RAM Stacks indeed!

Here is my 256K Stack, made with 15ns 32K SRAMs and a 3-8 decoder.
Great for dropping on a breadboard when you are out of 512K DIPs....



Brad

These are neither stacked nor DIP, but I thought it fit in here. This is the 8-way stacked QIP-bearing "module" found in a 1985 Cray-2: 300 modules, 750 chips on each, several hundred watts from each module, immersed in 200 gallons of pumped inert coolant. AFAICT, most of the memory chips (75000 of them) would be 256kbit. The logic chips are 16-gate programmable. Four heavy duty CPUs running at 240MHz. More detail here.

I'm going to have to say that I'm happy that I don't have to carry around 200 gallons of inert coolant to keep my iPhone from melting in to my leg every time I get a text.

What would be awesome is if someone made a complete SBC (without the board) using nothing but stacked IC's.

And no micro-contollers or PLD's.

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Cat; the other white meat.

Well, the problem you'd have there is the different package sizes and pin layouts. Stacked RAMs are relatively easy since only one pin needs to be seperately routed, but stacking a RAM, ROM, I/O, 6502 and Glue Logic would be a Frankenstein's Monster, methinks, not to mention a PITA to build.

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Want to design a PCB for your project? I strongly recommend KiCad. Its free, its multiplatform, and its easy to learn!
Also, I maintain KiCad libraries of Retro Computing and Arduino components you might find useful.

Exactly. Which is why it would be awesome.

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Cat; the other white meat.

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

As Dave would say, all of the electrons are going to fall out!

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Cat; the other white meat.

Challenge Accepted.

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Want to design a PCB for your project? I strongly recommend KiCad. Its free, its multiplatform, and its easy to learn!
Also, I maintain KiCad libraries of Retro Computing and Arduino components you might find useful.

Now, I would say PLCC-44 only for MPU and I/O but I think the Geneva Convention prohibits that kind of torcher.

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Cat; the other white meat.