OrCAD fun & games

Phil Munro wrote: : I'll be teaching a course starting Monday, and we will be using and : learning about OrCAD v10. We have demo version and licensed full : version access. I am using the full version.

: Just when I think I'm starting to figure our OrCAD, it will do : something crazy, giving me a message but not giving any answers.

Ummm, is there any reason you aren't using a free, open-source CAD package for your class? Both gEDA and Kicad are great for an academic setting, and your students can get fully-featured versions of these programs without shelling out scarce money for the software.

And if OrCAD is too buggy for the teacher, how will the students learn from it?

I often wonder why we teach students using programs they can't afford in school, aren't any better than the FOSS versions, and they may not use in real life anyway....

Stuart

That's what Task Manager is for. ;-) You should be able to identify the process that is running and kill it.

Best regards, Spehro Pefhany

...and if that won't do it:

You probably re-booted.

OrCAD Capture sucks the biggest lemon ;-)

...Jim Thompson

All software has a paradigm behind it, ie the expected way to use it.

ORCAD has the paradigm that they document and then there is the paradigm that works. Having used ORCAD capture and layout for over ten years it very rarely crashes on me, not because it has got better but because I know instinctively what works and it no longer even occurs to me to try any other way.

If you want to use the features that KiCad gives you then perhaps ORCAD looks better on your students CVs but don't expect to rely on any advanced features.

Colin

Am I right that people still don't like OrCAD Capture? On the other hand, I'm getting a little more comfortable with it. Interestingly, I did use task manager and close a program that was running and shouldn't have had anything to do with OrCAD; I did not reboot.

Thanks for the few useful comments besides those who think I should be using some other software. --Phil

OrCAD under DOS was a good program... under Windows it has gone steadily downhill... Cadence has about killed it.

...Jim Thompson

I never understand these sorts of posts. I've used layout since before ORCAD bought it (hence the .max extension (MaxEDA) for layout files) and capture since ver 5.something.

all the time, and don't like using newer versions than protel 99.

I would entirely agree that paying maintenance for ORCAD is money down the drain.

There are two things you can't do with layout, microvias (difficult to stop a microvia being put on top of a buried via) and decent SI controls such as length matching etc.

I have no spice experience so can't comment

Colin

Cadence discontinued direct sales of OrCad some time ago. It's still available, but only through 'partners'.

OrCad under Linux or Solaris (when part of the pack with Allegro) is far less crash prone, but has the same general issues it has under Windows.

My favourite internal gotcha with OrCad is if a net is dual aliased (for some reason), it can sometimes rename (effectively disconnecting) the net.

This happens if you alias a net offpage first, but not all the time - it's one of the reasons I manually check the nets in the netlist.

Have some net going to an offpage connector, and name it at the offpage connector (Offpage1, for instance).

Now go off and do some other stuff with a netlist in the middle (sanity check perhaps). Note that attaching an offpage connector with a valid name aliases the net automatically (and silently) on the same page.

Now name the net (with any name, same or different) and attach something else to the net (with a separate wire), using CTRL-N to alias that part of the net.

About 50% of the time, you'll get two different nets.

The percentage goes higher if you alias the net on another page (from that offpage connector) with a different name.

I have had this - I had a net (BATT_SENS) that went offpage, but had been aliased prior to this as BATTERY_SENSE. I cleaned up the aliasing (but without deleting the old wires and reconnecting).

I ended up with two nets (that according to OrCad internally were connected) in the netlist:

BATT_SENS BATT_SENS_Nxxxxxxxx (where Nxxxxxxxx is a standard autoname for a net in OrCad).

I was not amused when my battery sensing was not connected at the layout stage. As I said, that's why I now check my netlists manually from OrCad.

Cheers

PeteS

One of the reasons I still use SDT (Orcad's old DOS schematic program). Stable, fast, and produces solid net lists.

As does Ol' Original Flavor PSpice Schematics.

If you want the .INI file that allows Schematics to "talk", send me an E-mail.

...Jim Thompson

I'd suggest this isn't really the case. Just getting gEDA and Kicad

ORCAD is actually not particularly buggy in my opinion, compared to many other EDA packages I've used. To some extent this derives from the fact that ORCAD is a pretty mature product -- very little new development is occurring with it; it hasn't had any large changes in 5+ years now.

Because most students fully expect to work for employers who *will* be able to afford those package. In many companies, the cost of software tools is realatively small compared to the overall cost of doing business.

gEDA and Kicad don't seem to fall into this category yet.

The average student graduating this year or in the next few years has a far better chance of ending up using ORCAD commercially than gEDA or Kicad.

IMHO this largely parallels the fact that most universities have given up generating *high quality* software themselves. Why is it that SPICE, originally developed nearly 100% at universities, now has almost *no* ongoing development in academia? Most software that comes out of academia today is considerably buggier than what comes out of the open-source movement, much less commercial software houses.

There are also many features that ORCAD capture is missing that most other schematic capture tools have these days. I don't think there's anything inherently wrong with Cadence choosing to keep the ORCAD feature set pretty much frozen in time, but if *I'm* the one shelling out bucks for an EDA tool, it's very difficult to make ORCAD look like a good value proposition. The one area where it still tends to be much better than other programs is with the built-in database integratoin (CIS option) -- Pulsonix, Protel, Kicad, etc. don't even attempt to do this, last I looked.

I suspect that even Jim would admit that doing something that *should* be simple -- like overlaying a couple of simulator runs on top of each other on the same graph -- is a lot harder in PSpice than it should be!

I'm PSpice's biggest critic.

I don't do PCB, so I can't comment there, but Capture is just a

So I use the venerable original (MicroSim) PSpice Schematics.

As for overlaying multiple simulator runs on top of each other I have a trick...

(1) Print each run to a PostScript (*.ps) file

(2) Concatenate all your *.ps files along with the appropriate header and footer (?) using ConCat (from

(3) Edit out any conflicting/overlapping text.

(4) Convert to PDF with Adobe Acrobat

(?) Contact me for the header/footer files if you're interested.

...Jim Thompson

Hi Jim,

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

What's your opinion on how close LTSpice is to being ready for prime time? I'm guessing it lacks support for BSIM models, which I would imagine is a non-starter for you.

Yes, and it's a good trick; I just still consider it a lot harder than it should be -- other simulators I've used (such as SIMetrix) by default overlay all subsequent runs, and if/when you get sick of that you can specify each probe to have a "persistance" over a specified number of runs (e.g., setting it to 1 makes it behave like PSpice, I find it often useful to see the last

---Joel

I haven't tried but just a few things with LTspice, though it seems pretty robust. Actually I believe it does support BSIM3, but I'm not sure.

I'm not fond of its output GUI, and I'm REALLY fond of PSpice Schematics, so it's hard to pull me over ;-)

There's several other ploys in PSpice...

(1) Edit the *.CIR file to contain multiple runs, then the Probe output will be overlaid

(2) Save each run under a different name, then "Append" those DAT files.

...Jim Thompson

Also, if you are using Capture as the front end, you can set up multiple simulation profiles to generate individual runs that you then just load into Probe... 8-)

Charlie

One good deed doesn't offset 20 bad features ;-)

...Jim Thompson