Offpage connector symbols

D Yuniskis · 2010-01-19T21:17:24+00:00

Hi,As a side-comment to the schematic preferences thread(hopefully not another lengthy thread :> ), I'm curiousas to what folks use as an offpage connector symbol.Given that I prefer these to be *at* the edges of the schematic*and* given that the signal name will be "outboard" of it,I try to use very narrow symbols. And, since it is common forother such "offpage" symbols to be located immediately aboveand/or below, I try to keep the height of this symbol to"one intersignal spacing unit" (IsSU? :> ).I also like to show direction of signal flow in the symbol.This has led me to a set of six () symbols:Output RightInput Right (blech!)BiDir Rightand the corollaries for "Left". (I.e., left and right referto the edges of the page at which it is most appropriate toplace these symbols).For unidirectional signal flow, I use a pair of "concentric"(wrong word) arrow heads. E.g., >> or

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D Yuniskis 16 years ago

Yes. Though the schematic is the driving document in both cases. I.e., it wins all arguments ("Oh, I thought RESET was on pin 23..." "No, it's not.")

The biggest consumer of the document is the end user. He needs to be able to quickly understand what the design is trying to do and how it is trying to do it. To that end, you have to balance "information" with "clutter".

Ouch! Your schematics must be very "dark" :>

I only name things that *need* names. E.g., if I have an RC snubber across a switching diode, I don't name the signal

*between* the R and the C. Chances are, I will never have to refer to it in my written commentary. And, if I actually *do* need to refer to it (e.g., to tell a technician to probe the signal there), I would simply say "the junction of Rx and Cy".

Yes, but everything you put on a document is one more thing that has to be maintained. It's like putting comments on each line of code in a program. Or, using "FirstArrayIndex" and "SecondArrayIndex" (as in array[FirstArrayIndex][SecondArrayIndex]) instead of array[i][j]). I.e., it's just more than you need.

YMMV. The whole point of this was to elicit

*preferences* as none of these things are cast in stone...

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WangoTango 16 years ago

OK, well then who makes a symbol that isn't grouped into a cohesive unit, or what CAD package can't handle such things? All in/out/bi symbols I have EVER seen are not treated as individual parts/lines/primitives. They are a equivalent to a symbol or part that is manipulated as a unit. So ---> becomes --- rotating around what would be the electrical connection point. I guess I assumed you spent more than $1.50 on the software..... :)

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D Yuniskis 16 years ago

Sure. "Create a symbol". I think if you read upthread, that's where this discussion started.

If you are starting with;

--- ---< becomes >--- rotating around what would be the electrical

Only if that connection point is located in the *center* of the symbol. (Many eCAD packages put the PoE's on the *edge* of the symbol boundary).

This was OrCAD 9. I'll check Altium/Protel this afternoon if I get a chance. I know STRIDES would do it correctly (because I could always move the PoE manually if need be). I *really* don't want to fire up the Mentor Graphics workstation to see how *that* does it...

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D Yuniskis 16 years ago

Argh! I mispoke (confusing placement of signal name with signal PoE).

You have:

X--< SIGNALNAME

(standard OrCAD symbol "OFFPAGELEFT-L")

You want:

X--> SIGNALNAME

Tell me some combination of flips and rotates (remember, you're alleging that "silly me" doesn't need to bother editing the symbol itself -- creating a new one) will transform the first into the second?

Unhappy with "OFFPAGELEFT"? You can always try OFFPAGERIGHT:

SIGNALNAME >--X

But, I think you will find you can't rotate *that* either to get to

X--> SIGNALNAME

(even if you are willing to manually *move* "SIGNALNAME" each time you place a connector).

Perhaps your eCAD program works in N-dimensional space??

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WangoTango 16 years ago

Not in any package I have used. Maybe in some I evaluated and tossed out.

I have never had to get there to begin with.

Never seen a package where you couldn't add or expressly set the reference point location. I guess maybe I have just been lucky?

I used P-CAD which became Altium and it doesn't have any such issues, my ANCIENT DC-CAD no such problems, and I know CAD-Star handles things just fine too. Like I said, maybe I have just been lucky. Strange.

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WangoTango 16 years ago

I see. Now that makes sense. I never saw where you were referring to a signal name, just the symbol itself.

Well, now there's your problem. That doesn't even make sense for an off page left signal to me at all. Shouldn't that be :

off pageright X Bidir left X Bidir right

Where X is your electrical Connection AND rotation point?

I wasn't alleging anything. I guess I misunderstood your original point. I didn't understand that you were starting with a bizzaro symbol layout to begin with.

That looks more like onpage left to me.

No, it just didn't straddle me with some RPN-esque symbols from the get go. I'm sorry to have wasted your time.

I think that CAD-Star's default is to place the signal name over the 'wire' and then you move it to where you want. I will have to play again to find out. I only use P-CAD to support our older products, so I don't remember EXACTLY how it handles the names.

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larwe 16 years ago

of

I don't suppose you're hiring? :) This company has crossed the event horizon where it is no longer possible to do anything except procedure.

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krw 16 years ago

Not necessarily. In fact, it's dangerous to have the schematic be the definition of correct. The specification is *supposed* to be the definitive document. Also, it's not unusual to 'fix' the I/Os on an FPGA first. The schematic then picks up the pinouts from the FPGA.

The "end user" never sees our schematics. They see the product.

Confusing, too.

Test point: TP1234 ;-)

Sure, and it's been a good discussion. I think a lot of this stuff is driven by the tools used, though.

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Meindert Sprang 16 years ago

No, unfortunately not. Unless you bring in a couple of fine long term jobs, of course... :-)

Meindert

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JosephKK 16 years ago

snipped-for-privacy@seen.com=20

and

off-

that=20

I have not yet found a case where PoE itself was bidirectional. Of course Ethernet itself intrinsically is. It may be that=20 directionality being confused or conflated caused the symbol issues.

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