New software for schematic and simulation

[rapidcoder]

New software for design and simulation

Hello, everyone!

Together with a friend of mine, we are making a program for drawing schematics and analog/digital simulation. However, we do not want to make yet another Spice clone. Therefore, we want to ask you some questions:

1. What features would you like to have in such program, that are not present (or done badly) in the software you use?

2. Would you like to create device models for it, or help in some other way, e.g. by testing it, or even writing code?

Features we currently have or plan to have soon:
1. GUI for drawing schematics
2. Mixed-mode event driven simulation engine.
3. Interactive simulation, virtual instruments
4. Easy behavioral analog/digital device modeling
5. Programmable devices (programmed in any JVM language)
6. Works on Linux, Windows, Mac, Solaris and possibly Android (100% pure Java unlike most EDA software)

What do you think?

 

[john blue]

easily update database and add of components to the library
accuracy as close as to experimental results as possible

 

[cyberrat]

Import facilities so that circuits drawn in other CAD software work with it.

Most will output some form of ASCII data.

 

[rapidcoder]

As for import facilities: it is probably a lot of work, because there is no common standard there I guess. Do you know if they provide some documentation on the file formats? If not, reverse engineering them might be hard, even in textual form.

However, almost every schematic software I know of can export standard SPICE netlists (*.cir). What do you think of a feature like a SPICE netlist import? A netlist doesn't contain graphical information, but the elements, parameters and connections are all there. The user would probably have to manually improve the final layout of the schematic, but it is far less work than placing all the elements and wires from scratch. Wouldn't it be a good compromise? As a side effect, you could import some SPICE subcircuit models and convert them to schematics easily.

accuracy as close as to experimental results as possible

This depends mostly on the available models. Accurate SPICE-like models are complex and very slow. Simplified models are fast and can be a great use when doing switching circuits simulation. We leave it totally to the community - you can define your own models directly with equations. Probably there will be models with different levels of accuracy.
E.g. an ideal resistor can be modelled like that:

case class Resistor(
         id: Id,

        @ModelParam("R")
        @PhysicalUnit("Ohm")
        @Min(1e-6)
        @Max(1e+12)
        resistance: Double

) extends Model {

  @ModelTerminal("1")
  val _1 = AnalogTerminal(id.subId("1"))

  @ModelTerminal("2")
  val _2 = AnalogTerminal(id.subId("2"))

  @ModelEquation
  val eq1 = _1.current * resistance + _1.voltage - _2.voltage  

  @ModelEquation
  val eq2 = _1.current + _2.current
}

The models can be added dynamically to the database without restarting (digital models, containing "real code", too). You can freely mix digital and analog models, even more, you can have a mixed model containing analog equations **and** some code.