Circuit Simulation and Fabrication

Jim McCorison

Greetings All,

I have been told that it is possible to completely develop and simulate an analog / digital design in software, then ship the resulting design off to be fab'ed. The actual device never sees the light of day until it is in production. Do any of you know anything about this methodology of development? Can any of you recommend quality simulation software that will accomodate the Basic Stamp, PIC, or other microcontroller. And before anybody tells me, yes, I know this stuff usually isn't cheap. So far I've found everything from free (ngSpice) to $25,000!!! And that's just for the basic software.

Thanks in advance for any help you might have,
Jim

KenM

For the SX micro sold and supported in one of these Parallax forums, there is a free simulator for the device.

The last time I looked at it (and it works well by the way) it can only simulate digital I/O via clicking a button on or off, not by connecting discrete components to I/O.

Ken

Jim McCorison

Thanks. I've seen the SX simulator. What I'm hoping to do is simulate everything, analog, digital, microcontroller s/w, etc. in software first. Among other reasons, I live on a boat and my wife gets a little testy if my projects spread out too much, or don't get put away as soon as I stop working on them. We've only one table which is in the middle of everything. If I could do everything on a laptop it would minimize clutter, and that would make her happy.

Jim McCorison

I think I stumbled upon an answer to my own question over in the BASIC Stamp forum. (see thread at http://forums.parallax.com/showthread.php?p=520928.) The folks from Labcenter Electronics in the UK (www.labcenter.co.uk) have exactly what I am looking for. Their Proteus simulator product covers a wide range of chips including the BASIC Stamp Starter for 99 pounds which simulates the BS2, to the BS Complete with the rest of the BS chips. The also have versions for the Amtel, 8051, HC11, and various PIC chips. You can download a demo version which includes various sample exercises for a variety of chips. The demo version includes something like 8,000 different components, and they say that is only a subset of the total number that ship with the full version.

Kind of neat, if you want to try simulators out. Just think... no more smoke.

allanlane5

That is neat. Be aware, though that you can't do EVERYTHING in software simulation. The 'real' hardware will have a few gotcha's in terms of grounding, RF-noise effects, power-supply, ripple, etc.

Having said that, software simulation can at least let you iron out the major functional aspects of what you are trying to do, so it can reduce the number of iterations of board design to hardware implementation to board test. You may need two or three board revisions to get it all correct, instead of 5 to 10.

Bean

I agree, I've seen too many things go wrong. I would NEVER put a board into production without making a prototype. (ok unless it it something VERY simple).

Also often it is in testing the prototype that improvements can be made to a design. Many things just don't stand out on paper (or a computer screen) until you see the actual product.


Bean.

Jim McCorison

Agreed. I certainly wouldn't go into full production straight out of the computer. After all, I'm not Boeing designing something simple like an airplane.

But seriously, I would produce samples first. I'd test in the real world, which is cruising boats. Then I'd give one to my wife, who is reasonably button-phobic, to see if the UI passed the test.

Cheers,
Jim