
Core Memory Upgrade for Arduino - ingve
https://hackaday.com/2018/04/28/core-memory-upgrade-for-arduino/
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userbinator
Core eventually miniaturised into
[https://en.wikipedia.org/wiki/Ferroelectric_RAM](https://en.wikipedia.org/wiki/Ferroelectric_RAM)
, which remains in limited use (TI has a series of MCUs with FRAM instead of
EEPROM) --- and one curious application is in the toner cartridge DRM chip of
a Lexmark laser printer, for which there is this ongoing reverse-engineering
effort:

[https://www.eevblog.com/forum/projects/lexmark-toner-chip-
ti...](https://www.eevblog.com/forum/projects/lexmark-toner-chip-ti046b1/)

(Normally those use EEPROMs, so the choice of FRAM is a bit odd.)

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TickleSteve
You make it sound as tho FRAM is old technology... its actually just starting
to be used in volume (in microcontroller based systems). FRAM has some very
desirable properties compared to current technology uC that use both SRAM &
FLASH. Its still slightly expensive at this point in time but that will solve
itself in time.

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dcbadacd
> FRAM has some very desirable properties compared to current technology uC
> that use both SRAM & FLASH.

Could you please elaborate?

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nerfhammer
it's as fast as sram but persists like flash

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codezero
If you want to spend a while learning more about how magnetic cores work check
out these videos made by the US Army in the 60s:

[https://m.youtube.com/watch?v=HPT7Wtp3yoo](https://m.youtube.com/watch?v=HPT7Wtp3yoo)
[https://m.youtube.com/watch?v=An-GIhx0z4c](https://m.youtube.com/watch?v=An-
GIhx0z4c)

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primitur
I wonder if there is anything unique about this that might make it interesting
to use in a sampler or a synthesizer or something .. maybe some random noises
that could be generated by stroking the core, or some such things ..

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vegetablepotpie
I doubt that storing digital representations of sounds on the cores and then
stroking the cores would result in any modification of the data. You could run
a wire with current next to the cores to induce bit flips, but what happens to
the sound would depend on the format of the data stored on them.

You could put an inductor in or around the array, which could pick up magnetic
impulses from currents used to program the cores. If you amplify the voltage
coming out of the inductor and sample that, it could result in interesting
random sounds.

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MisterTea
> Of course, the Arduino can’t directly run programs out of the memory...

Use the Atmel ATmega2650's external memory bus on the mega and you could. Or
at the very least, a few variables.

