7 ms·
This is a fascinating article. Footnote 8 is an especially fascinating insight; > One puzzling feature of the shift register is that there is no wiring betwe
by phab 8y ago
This is a fascinating article. Footnote 8 is an especially fascinating insight;
> One puzzling feature of the shift register is that there is no wiring between the stages!
> How do bits get from one stage to the next? Did the chip have another layer of wiring that wasn't in
> the photos? Was there some sort of hidden connection? Eventually I noticed that there wasn't an isolation
> ring between the stages—a silicon barrier that separated most I2L circuits. Without this isolation ring,
> an "invisible" PNP transistor exists between the stages, apparently allowing one stage to flip the next
> stage to the right value. Each shift-register stage is constructed from two NAND-gate latches. When the
> clock is low, the first latch is forced into an indeterminate state. When the clock goes high, the latch
> ends up as 0 or 1 based on the bias it receives from the previous stage through the "invisible" PNP
> transistors. Thus, the latch becomes edge-sensitive since it will change right on the clock's rising edge.
> I found a paper ("Injection-Coupled Synchronous Logic", 1978) that describes a similar technique for an I2L
> shift register9, so I think this is the right explanation, even though the circuit seems a bit sketchy.
- sjwright 8y agoA direct link to the footnote, as the above is unreadable. (Hint: don’t use code formatting for quotes. It is semantically wrong and is unreadable on many devices.) http://www.righto.com/2018/05/inside-76477-space-invaders-sound.html?m=1#fn:connection http://www.righto.com/2018/05/inside-76477-space-invaders-so...
- digi_owl 8y agoThe basic problem is that it is "labeled" as a form of quote...
- phab 8y agoI'm curious as to why you find this unreadable... it renders pretty readably for me? (https://pasteboard.co/HlW8oMh.png https://pasteboard.co/HlW8oMh.png). As far as I can tell, formatdoc[0] doesn't provide a "semantically correct" method for formatting quotes. Hence, the age-old usenet quote (as codified in RFC3676[1]) seems to me to be the best way of indicating a quotation, and rendering it via a verbatim block ensures that the line-based quotation indication isn't disrupted by the text all being in a <p> tag when rendered in HTML. [0] https://news.ycombinator.com/formatdoc https://news.ycombinator.com/formatdoc [1] http://www.ietf.org/rfc/rfc3676.txt http://www.ietf.org/rfc/rfc3676.txt
- CamperBob2 8y agoSemantically wrong or not, it's all the HN developers have chosen to give us for blockquoting. That's not the users' fault. For mobile, it helps if you manually truncate lines, like so: One puzzling feature of the shift register is that there is no wiring between the stages! How do bits get from one stage to the next? Did the chip have another layer of wiring that wasn't in the photos? Was there some sort of hidden connection? Eventually I noticed that there wasn't an isolation ring between the stages—a silicon barrier that separated most I2L circuits. Without this isolation ring, an "invisible" PNP transistor exists between The site is called "Hacker News," after all. Apparently that's because we're expected to, well, hack.
- scarface74 8y agoItalics are more readable.
- CamperBob2 8y agoAnd semantically just as broken. Would it be that hard for the '1337 h4x04s at YC to support '>' blockquote markup like so many other forums?
- scarface74 8y agoSo what's more important "semantic correctness" or having a readable post?
- CamperBob2 8y agoThat question excludes an obvious middle ground, which is supporting a reasonable feature set in the BBS software so that the question never even comes up. Let's stop carrying water for lazy programmers. The lack of a proper quoting syntax has been a problem on HN for a long time.
- scarface74 8y ago
- pasbesoin 8y agoOn HN, you can just "star" the paste at the beginning and end. One puzzling feature of the shift register is that there is no wiring between the stages! How do bits get from one stage to the next? Did the chip have another layer of wiring that wasn't in the photos? Was there some sort of hidden connection? Eventually I noticed that there wasn't an isolation ring between the stages—a silicon barrier that separated most I2L circuits. Without this isolation ring, an "invisible" PNP transistor exists between the stages, apparently allowing one stage to flip the next stage to the right value. Each shift-register stage is constructed from two NAND-gate latches. When the clock is low, the first latch is forced into an indeterminate state. When the clock goes high, the latch ends up as 0 or 1 based on the bias it receives from the previous stage through the "invisible" PNP transistors. Thus, the latch becomes edge-sensitive since it will change right on the clock's rising edge. I found a paper ("Injection-Coupled Synchronous Logic", 1978) that describes a similar technique for an I2L shift register9, so I think this is the right explanation, even though the circuit seems a bit sketchy.
- deleted 8y ago[deleted]