Schematic preferences
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From: D Yuniskis on 19 Jan 2010 13:58 Joel Koltner wrote: > "krw" <krw(a)att.bizzzzzzzzzzz> wrote in message > news:1gbal51s9jie6of3ufcf6u98codr531qi3(a)4ax.com... >> I really don't like prefixes (other than power) because the signal >> names don't collate properly. A net and its negative should sort >> together, just as diff pairs should sort together. > > Good point. With a few macros in your favorite text editor this is > pretty easy to "fix," but I can see how that could be more hassle than > it's worth. > > Our schematics often have many hundreds of nets (often over a thousand) > of which typically fewer than 10% are actually named something > meaningful (the rest just being NET0001, NET0002, or whatever the > software uses by default). How about yours? This is the result of either enforcing a name on every signal *or* cutting the schematic into too many pieces (I only require names on signals that go off-page). I worked on a project for a three letter company many years ago. The "boards" were mounted on gates (doors?). I would estimate 2,000-3,000 DIPS on a board (plus two or three decoupling caps per component). Highly repetive design (is that the right way to say that? seems clumsy). Someone could flip the page in the "schematic book" while you weren't looking and you would never know it! Components were all boxes, signals were all plain vanilla names ("Gee, I thought I was just checking on NET1234 yet the schematic says NET2042... <shrug>") You really want the drawing to work *with* you and not against you (e.g., Sl vs. S1 is not a good idea!)
From: D Yuniskis on 19 Jan 2010 14:03 Joel Koltner wrote: > "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in > message news:o3nbl55g2cpeqcso7g0in089sm2hpdv700(a)4ax.com... >> The opposite extreme is amateurs that make up prefixes... TR for >> transistor, RV for pot (RV actually designates a Recreational >> Vehicle), LED for LED even! > > TR and RV are arguably signs of not being familiar with industry > standards. LED I could imagine someone purposely choosing even though > they're well aware that normally it's just D, i.e., they believe they're > creating an improvement. Whether or not that's really the case is pretty > subjective, although it's pretty hard to argue that someone seeing a > reference designator of LED23 wouldn't understand what kind of component > it is. :-) Worse yet is using 'D' but failing to use an LED *graphic* to show that the device emits light! >> Most annoying, especially when combined with the dreadful 2K7 notation >> and the accompanying bad circuits. > > 2k7 is a European thing. As with four-way intersections, historically > there was some decent justification for it (the decimal point easily > getting lost in mechanical reproductions), whereas today it's just a > personal preference, I suppose. I have mixed feelings about 2K7, etc. If you complain about dots (disappearing *or* appearing) in 4WS's, then you can argue that the 2K7 notation reduces the possibility of losing a '.' in document reproduction. Not a big deal nowadays as most lettering is done "by machine". But, when it was done with pointed lead and lettering guide, it would be easy for "2.7" to look like "27" when reproduced (as the '.' need not take up as much horizontal space as a digit! i.e., you won't necessarily see "2.7" appear as "2 7")
From: Nico Coesel on 19 Jan 2010 13:53 D Yuniskis <not.going.to.be(a)seen.com> wrote: >Hi, > >Of course, this is *highly* subjective -- but, I'd enjoy hearing >folks' "conventions" used when preparing schematics (that *others* >will consume -- how you scribble for your own purposes isn't >important as it depends a lot on what *you* want out of the >drawing). > >I try to follow some general rules -- but also feel free to bend >them as needed. Most have evolved over the years from different >employers, standards, experience, etc. > >E.g., I *tend* to prefer landscape orientation -- though I >drew a B size "portrait" this morning in lieu of a C size >landscape. That depends on your printer. On a shitty printer A4/letter size may be the maximum for a readable diagram while a good printer will allow for much more on one page. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico(a)nctdevpuntnl (punt=.) --------------------------------------------------------------
From: Jim Thompson on 19 Jan 2010 14:04 On Tue, 19 Jan 2010 18:53:02 GMT, nico(a)puntnl.niks (Nico Coesel) wrote: >D Yuniskis <not.going.to.be(a)seen.com> wrote: > >>Hi, >> >>Of course, this is *highly* subjective -- but, I'd enjoy hearing >>folks' "conventions" used when preparing schematics (that *others* >>will consume -- how you scribble for your own purposes isn't >>important as it depends a lot on what *you* want out of the >>drawing). >> >>I try to follow some general rules -- but also feel free to bend >>them as needed. Most have evolved over the years from different >>employers, standards, experience, etc. >> >>E.g., I *tend* to prefer landscape orientation -- though I >>drew a B size "portrait" this morning in lieu of a C size >>landscape. > >That depends on your printer. On a shitty printer A4/letter size may >be the maximum for a readable diagram while a good printer will allow >for much more on one page. I rarely produce paper schematics... everything is distributed via Acrobat... everything from A to E-size. Thus my layout guy can then zoom in for something he can't quite make out. (The ultimate check is called "LVS", layout-vs-schematic, where netlists I generate are compared to the netlists that the layout program generates.) I've also kissed off Power Point for presentations. I can do it better in Acrobat with "push/pop" hierarchical schematics, allowing me to zip around during design reviews to exactly what the audience wants to see. I can print up to 13" x 19" on my wife's HP Officejet Pro K850, but I rarely do. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
From: Tim Wescott on 19 Jan 2010 14:16
On Mon, 18 Jan 2010 13:37:16 -0700, D Yuniskis wrote: > Hi, > -- snip -- > > I try to include a block diagram of any "sizable" design early in the > document. I try to draft the individual pages so that they roughly > correspond with the blocks in that diagram. > -- snip -- Having worked on a number of complex boards whose schematics run to a dozen pages or more, I have developed a great liking for schematic capture tools that do hierarchical schematics. You do the block diagram, and then the tool _embodies_ the block diagram. (This, of course, like anything else*, can be misused. But done with a minimum amount of care and some appropriately gleeful criticism from your peers, it clarifies things a lot). * even commas. -- www.wescottdesign.com |