Zilog Z80 bites the dust

dougw 11 months ago

I just noticed this extinction event.

Littelfuse who own the Zilog Z80 IP announced the Z80 would cease production in June 2024. (Semiconductor fab lines are not interested in running a 4 micron process)

Fortunately the eZ80 system-on-a-chip is still in production if you want to pursue this technology.

At one time I was ultra keen to obtain or build a Z80 microcomputer, but never managed to scrounge enough money until recently when I made a low cost emulator on an ESP32....

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0 colporteur 11 months ago

Play taps for the Z80 housed in a Sinclair.
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0 md_steve 11 months ago in reply to colporteur

I ordered a Sinclair kit but it was backordered. Much to my surprise, the next month they sent me a fully assembled unit!
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0 dang74 11 months ago in reply to shabaz

Just read the excerpt you posted. I've suffered a bit in PCB layout when it's a challenge to fit everything onto a tiny board... but yeah what Federico went through would have been a hundred times worse.
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0 shabaz 11 months ago in reply to dang74

Hehe yes, it's quite interesting, having never done chip design, I would never have thought there could be such a simple problem, but it totally makes sense, that in the manual drafting days, once one dimension of the chip was established, you kind of just had to continue designing the chip to be as long as required to fit all the functionality : )
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0 dang74 11 months ago in reply to shabaz

Yeah, I try and imagine it as having the constant fear of painting yourself in a corner.
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0 dougw 11 months ago in reply to dang74

When laying out with tape, you can't even see the corners, which are in different directions on different layers, until it is too late. Sometimes they are more like land mines hidden on different layers....
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0 dang74 11 months ago in reply to dougw

Land mine is a scarier analogy than paint.... and I'll have to read up on historic IC design to fully appreciate your post. Sounds like you aren't talking about fitting concerns but accidentally connecting to the trace on a layer you can't see. If so, then yeah, land mine sounds about right.
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0 michaelkellett 11 months ago in reply to dougw

We used translucent tape (blue and red) for top and bottom.

I did the initial design with 1:1 scaling on 0.1" graph paper using blue and red pencils - the tape up was 2:1.

Never had to tape up anything worse than two layers before PCB CAD on PC turned up and saved the day !.

MK
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0 dougw 11 months ago in reply to dang74

Transistors necessarily have overlapping structures but the amount of overlap affects properties of the transistors including diffusion of impurities to dope the silicon. It was much more than just a 3D juggling act.
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0 dang74 11 months ago in reply to dougw

Thanks Doug. I have a clearer picture now.
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