Eagle CAD schematic to simulation

[anishkgt]

Could anybody please recommend me a simulation software that would work with Eagle. i hear there is LTSpice but which version. There are a bunch of the versions and not sure which to to go for. Are there any simpler ones than LTSpice ?

[ataradov]

Schematics for simulation and schematics for design are two very different things, I doubt you will find a good solution.

Just use LTSpice for simulation.

[anishkgt]

Basically I need to simulate my schematic and LTspice has lot of versions. Is it LTSpice IV that I should go for ?

[ataradov]

Yes, LTSpice IV is the latest version, there is not reason not to use it.

[anishkgt]

Thanks Alex.

Would this be rite forum to ask questions about ltspice ? Tried importing my schematic but errors were shown when exporting an LED. "Different quantities and spice order.....". Does it mean I have to create a new kit ray for led.

[ataradov]

Would this be rite forum to ask questions about ltspice ?

Sure, why not?

Tried importing my schematic

Importing from where?

It is highly likely that you will have to re-create the schematic in LTSpice from scratch. I doubt there is a reliable way to import from anything but other SPICE-type program. As I said, two different things with completely different approaches to schematic representation.

[anishkgt]

you will have to re-create the schematic in LTSpice from scratch.

That's is gonna be hard. Isn't there a easier way to do this. The eagle schematic has a link that says export. So probably there should be a way to do this but could not find a straight forward way to do it.

How does the others do it ?

[ataradov]

That's is gonna be hard.

Why?

How does the others do it ?

They don't. You can draw whatever you want in Eagle, but if there are no corresponding SPICE models, then you will be out of luck.

Simulation schematic is VERY different from design schematic, for anything non-trivial there is no direct correspondence.

[tatus1969]

they have added an LT spice export function in Eagle, but i have never used it. your eagle design probably only contains geometrical data of your parts, so you will have to create all the necessary electrical data by yourself anyway. better start from scratch and concentrate on specific areas of your whole circuit only. LTspice is the simplest tool that i know, but your question suggests: are you aware that circuit simulation is a complex topic itself?

[Karel]

http://felicitas-ce.de/product/pcbsim/

[anishkgt]

Thanks guys. Will try all from scratch on spice and see how it goes.

[anishkgt]

So i just tried out the LTSpice IV and suprisingly i could not find some devices in it. like the ATmega328P. is this version of the simulation limited to some components and the the versions of spice would be having.

[ataradov]

like the ATmega328P

That's exactly what I wast talking about. It is impossible to do SPICE simulation on a micro controller. SPICE builds and solves a system of differential equations, so it does not support anything programmable. You typically use simulations to figure out details of reasonably small sub-circuits, not the whole thing.

There are things like MultiSim that try to to this, but they fail real fast, so just forget that you can do a simulation like that and have reliable results.

[anishkgt]

ah silly me, wasting time with simulation. but i am glad, i now know its simulators are not completely here to simulate a complete schematic. Then i guess its time to do it the age old way, print, Photoresist and finally etching.

[ataradov]

simulators are not completely here to simulate a complete schematic.

And they never will be, because it is a pretty pointless exercise.  Complete simulation of everything would be impossible, and trying to simulate every single MCU out there is a huge task, and there is no way anyone will get a return on investment on this.

[tatus1969]

ah silly me, wasting time with simulation. but i am glad, i now know its simulators are not completely here to simulate a complete schematic. Then i guess its time to do it the age old way, print, Photoresist and finally etching.

as I said, concentrate on specific aspects of your circuit. The first question should be: what specifically do I want to know about my circuit?

[anishkgt]

i was trying to test the whole circuit as etching process does take time since that would not work, specifically test if the 2 scr in back to back configuration would work as per the configuration on their datasheet.

[ataradov]

specifically test if the 2 scr in back to back configuration would work as per the configuration on their datasheet.

What is "scr"? That specific part sounds exactly like something you would test in LTSpice. You don't need MCU for that. Unless "scr" is something programmable, in which case simulation is not likely to be accurate anyway.

[anishkgt]

Scr is silicon controlled rectifier or a thyristor. Hmm will have to see that then. What is spice XVII?

[ataradov]

Ant reasons not using XVII? I heard it's a bit buggy, but anyway it works for me.

I did not know it existed There does not seem to be a whole lot of improvements compared to IV, but sure, I'll check that the next time I need to install LTSpice. For now, I don't see anything exiting to update immediately.

[ataradov]

Scr is silicon controlled rectifier or a thyristor.

Quick search turns up this https://www.eevblog.com/forum/projects/ltspice-thyristorscr-library/ How well those libraries are matched  with real devices - who knows. For anything critical or unusual uses, I'd just assemble a real deal sub-circuit.

Hmm will have to see that then. What is spice XVII?

http://www.linear.com/designtools/software/