Author Topic: Pictures of Vintage ICs  (Read 4090 times)

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Offline joeqsmith

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Re: Pictures of Vintage ICs
« Reply #25 on: February 28, 2018, 02:53:04 am »
At some intermediate step in the evolution of microcontrollers, we didn't have the technology to make non-volatile memory and the processor logic on the same chip. So kludgy things like this were used to combine the firmware storage on an EPROM which plugged into the CPU package.
AFAIK these were also the first of a kind versions for a new microcontroller to be able to easily "reprogram" during debugging instead of erasing the processor you had a bunch op eproms which were much cheaper to have around.
I could repair a Philips laservision player from the begin of the 70s just because they had these piggyback chips  :)
I plugged a ROM emulator into that Hitachi part to develop the code for the transient generator.   
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Offline Alex Eisenhut

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Re: Pictures of Vintage ICs
« Reply #26 on: February 28, 2018, 03:54:37 am »
Still got this little gem in its original alufoiled inside covered box, 24kB SRAM for the Tandy Model 200.
They only had 8kB chips in those days so they put three of them on a ceramic carrier and added a H138 address decoder  :)




That would look sweet on my VIC-20...
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Online dexters_lab

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Re: Pictures of Vintage ICs
« Reply #27 on: February 28, 2018, 09:01:16 am »
those ceramic hybrid sram things seem to have been very popular, did the sram makers stop making them in pdip or something? :-//
I am not exactly sure that I understand your question.
In any case the Tandy Model200 and 100 were the portable small computers of that day, lcd display, running on AA batteries for what I remember 12 hours or something like that, size did matter. So 8kB pdip srams would occupy too much space.

there just seems to be a lot of ceramic pdip hybrids that have multiple smd srams mounted on them, i have some in my little collection, like the world needed pdip parts but the makers were only producing smd
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