Justin DavisSo I'm already running into difficulties with parts. Fortunately I can dig well and came up with this guy:
http://www.ti.com/product/SN54LS181/description
It's an active 181 ALU. Sure it's the 54181, but it will work just fine. I'm not against the 5400 series. And it makes my life much easier. And it's an active device, so it qualifies. Sure it's just 4-bit, but it's easy to gang them together.
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I'm not able to find a '381 that's active (or '382). Plus it's not cascade-able because it doesn't have a carry-out bit. I think I can make do with two '181s.
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it's cascadable, IIRC, because it exposes the Propagate and Generate signals.
OK, I don't know either how to use these :-D
Yes, the '181 is bulky but usually a good bet (and nice heater for the long winter nights)
Do you really need "active" parts ? I did find some 381 on the 'bay.
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Even though this is a personal project, I find it difficult to break away from good design practices. One of the highest is don't use obsolete components. If anyone else wants to build the project, I'll want them to gets parts easily. And obsolete components are often more expensive and of questionable quality and functionality. I don't really trust a chip that's been sitting on a shelf for 10-15 years.
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The '181 seems to be trendy these days :-)
I got a few vintage ones https://hackaday.io/project/8121-discrete-yasep/log/28438-what-chips-for-the-alu and I've seen it appear on several projects here, as well as on the main hackaday.com site
https://hackaday.com/2017/03/27/explaining-the-operation-of-the-74181-alu/
https://hackaday.com/2017/01/07/yes-you-can-reverse-engineer-this-74181/
The 381 might be more convenient and smaller as well.
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