Offpage connector symbols

I use bigger things with the signal name inside--arrow directed outwards for outputs, inwards for inputs, like this:

/------------ < CONV_CLOCK |----- and \------------

---| DONE >

Cheers

Phil Hobbs Dr Philip C D Hobbs Principal ElectroOptical Innovations

email: hobbs at electrooptical dot net

Nah, I do it in pencil--the name can be as long as my ruler. ;)

Cheers

Phil Hobbs

Yeah, but that implicitly limits the length of a signal name. I opted for small symbols (so they don't consume much lateral space) which lets me dynamically rearrange the space adjacent to the symbol for a lengthier name, etc. :-/

Most of the schematic editors I've used distinguish an innie from an outie, at least graphically (if not as part of a hierarchical schematic editor that even does some rules checking, like no nets with all inputs, no nets with two alway-on outputs, etc).

That's why it's important to make sure the pin attribute on such connectors is correct.

ted text -

Yes!! Working in production is one thing, fixing it in the field is something else!

For me, I definitely prefer signal names inside the offpage connector (arrow). NOT adjacent to the connector, or squished between the lines. Very cumbersome outside the factory.

Also, try to avoid all nomenclatures that attempt to describe the function (such as "in" or "out", etc..) when the interpretation depends on some outside intervention (such as the prespective of the tech).

For example, I wouldn't recommend using "Audio Out Right" because that same term won't make any sense when it gets to where it's going. Try "Unamplified Audio, R+", or something like that.

You get the idea.

Jesus H. Christ on a stick YES. Every, EVERY time we have to connect two boards that have "RXD, TXD, GND", there is confusion over whether that means "data from me to you" or "data from you to me". ARGHHH!! We have literally boards that go through six "flips" of RX/TX lines because of this. Each time something in the middle got revved, someone got it wrong, and someone else added a buffer and a flip in a different subsystem.

Pretty much. Output right (input left) makes sense at times, though I try not to use them either.

Yeah, I'd like to fit the sheet number cross references in there, but that's asking for too much.

Diamond works for me.

Wouldn't it be simpler to have pads for zero ohm resistors to configure the port? Or two positions to put the connector to chose the right configuration?

The subsystems are designed by different groups, and the adage about design resembling organizational structure is completely true.

I use a CAD program. It has "input", "output", "bidirectional", and "passive" (none of the above, AKA don't care) for off-page and off- sheet.

I've never seen a reason to change them from the default.

AL

This is, by far, the best idea that this thread has dredged up! I'm not sure that it can be done universally, though. E.g., you may *think* your signals are "the end of the line"...

To build on your example, designing a home stereo you would *think* that "left" and "right" are intuitive *and* descriptive. Yet, if someone plugs something else into it, all bets are off.

I frequently have to check manuals when hooking up record/playback devices to stereos, for example: is Tape In an input *from* the tape deck or an output *to* the Input on the Tape deck, etc.

I'll have to reexamine designs I have done over the years to see how I could have changed things to be less "descriptive" :>

Thanks!

Yes, all of the tools I use do this. I am just not happy with their symbol choices. And, since I can change them, I have.

E.g., I don't like an output on the right side of the page drawn as <

The canned OrCrap symbols don't include all six varieties. We don't have them in our library (gotta talk to the librarian again...) so I copy them from another schematic when I need them.

Mmm.... time for some company-wide standard design rules?

Meindert

Something to bear in mind is that many users of your design won't use the schematic, eg your layout guy isn't going to look at the schematic for every net he picks up, nor is your firmware guy going to constantly check when he defines and uses an FPGA pin. We name almost every net on the board :-

{source}_{destination}_{major function name}_{minor function name}

With not much thought you can define three letter acronyms for every source and destination and probably major function name. Suddenly you have a schematic where you don't have to drill up and down through hierarchy and fewer mistakes are made.

Colin

Believe me when I tell you the last thing this company needs is any more rules or procedures.

I know (from your earlier posts :-) ). Lucky for me I'm on the other end of the scale. I'm the only engineer here, accounting for 50% of the eployees and 100% for management :-)

Meindert

I guess your CAD package doesn't have a rotate or flip? Funny what these guys will forget. ;)