Hi,

[2]
I am considering purchasing a circuit simulation program. I downloaded a program called Proteus Lite from ZDnet and it seems to be a nice and powerful program. However, it doesn't have an SXfamily of chips. It does seem to have basic stamp examples though. Is there a simulation program that does? Preferably one that won't cost an arm and a leg and an irate wife? Or, if someone is already using this program or another like it I think there is a way to import new devices. Any thoughts and recommendations would be appreciated.
[/2]Thanks,
Jim W.

Jim,
Such a simulator is built right into the SX-Key IDE, known as SXSIM. Download and install the IDE and you can run our sample programs.

It's free, too.

Ken Gracey
Parallax, Inc.

I think Jim is looking for a simulator of electronic circuits that include the SX. There are none that I am aware of which can simulate both the SX and a circuit without costing a pretty good chunk of change.

The closest thing I've seen is
http://www.feertech.com/misim/homepage.html which will simulate PIC 16c57 chips (which the SX 28 is a superset of) while also simulating some types of external circuitry connected to the microcontroller.

Years ago I tried to get Ubicom (then Scenix) to fund the inclusion of the SX into MiSim, but it didn't happen. In a way, I'm glad because we would probably not have the very nice SXSIM, but the ability to simulate external hardware is important and lacking.

I seem to remember some talk a long time ago about the idea of somehow interfacing SXSIM to one of the open source spice simulators.

Having said all of that: I will again say something contriversial (amazing huh?)

Simulation sucks. The BEST feature of the SX chip is that you can build the circuit, put the SX in it, and via the SX KEY, actually watch the SX run and see what is happening inside the chip. In my (never) humble opinion, that is worth a 1000 simulators.

HI Jim,
Freetech.com looks like a good place. I wiil try it. You can also try a free trail of proteus lite that also has the 16c57. I think this is the link, http://downloads.zdnet.com/download.aspx?&compid=40890&docid=206986 I was just hopping for a real SX to play with.

You said "Simulation sucks" It may not be the real thing but its a nice way to experiment when you have a what if idea. The other features like schematic drawing and pcb layout are handy too.

Jim,
The SX Blitz is $29.95 and the SX Proto Boards are $10, so you're ready to rumble for $40 plus shipping. SX/B is free. When you place your order send me a PM and I'll even throw in a few SX chips just to get you started.

As for the PCB schematic and layout, the preferred tool of choice for customers on this forum is Eagle. You can download it for free and produce boards for non-profit, and pay them when you're ready to build a product.

Couple more ideas for you. I've seen Proteus before, but often find that programming the real thing is more fun.

Ken Gracey
Parallax, Inc.

Jim,
although I have written SXSim, and made it available for free to the public domain, I must admit that the best and fastest SX simulator is the SX itself, together with an SX-Key, and the SX-Key IDE software.

I understand that you are looking for some hardware simulation software that allows to simulate an SX connected to "virtual" external components. I have several simulation programs available here, like the Electronics Workbench. None of these can simulate such a complex device like the SX, and I must admit that I'm not very happy with such kind of simulators at all. Maybe, this is because I started working with electronics long before PCs and simulation software was available. So I still prefer the "breadbording" approach, i.e. I like building a "real" prototype, and to test it using "real" equipement, like an o-scope, or a multi-meter. The nice thing with the SX is that in most applications, external hardware can be reduced to just a few components, and all the logic is done inside the SX, software-controlled.

I personally know at least one guy who can type working SX assembly code faster than you and I can type the text for a forum message, so this guy thinks the SX-Debugger is for wimps only. Maybe, he is right, but I must admit that I still belong to the "wimpy" group of SX Debugger users :-) .

I guess I can admit that simulation is good for trying out a quick idea or watching a snipet of code execute when it doesn't involve interaction with the outside world. It is also good for education and demostration.

Still, best to stick with a breadboard and an SX for real development. CAD software when you are ready to publish or produce.

Hi all-
I have the beginnings of a Proteus "plug in" that simulates the SX-28.   It currently executes SX-28 code within Proteus VMS just fine but I have not (yet) implemented the debug/single-step interface(s).  Here is the loose end:  My understanding is that the free/low-end Proteus versions are not really useful with simulations, especial with microprocessor simulations.  In addition, a license addition (which appears to be no-cost) is needed from LabCenter (suppliers of Proteus) to run external "plug ins" -- I had no problems getting a license addition from them.  I have connected switches, resistors and LEDs to this virtual SX-28, started the simulation -- and watched the SX-28 receive inputs and drive the outputs (in my simple test case, LEDs blinking).....

If there is someone who has a commercial-grade version of Proteus who is interested in running SX-28 code in their simulations, please contact me.

The SX-28 capability being used is the open-source SX-28 I have supplied at www.rwsenser.com.  I am in the process of adding "middleware" that connects this existing simulation/emulation code to VMS, using the Proteus VMS SDK.  The end result is a Windows DLL that Proteus calls from its "Models" directory.  I have to say that although I've only been using Proteus for about a month, I find I really like the way it works and what it can do.

Thank you all for your inputs,
I would be like a baby alone in the woods without this forum. There is one other reason I'm interested in simulation software, it's because I am sometimes on the road for months at a time and can't bring my toys with me. Being able to run simulation from my laptop would be a fine substitute to watching TV or getting sauced at the bar. It would be great to have the ability to continue working on the project I was working on when I left.

RW Senser
I am going to register my copy today and I would be interested  in your plug in if you would care to share it.

Best,
Jim W.

Hi Jim W.,
The "plug in" is at the "working prototype" stage -- and I would be happy to get you a copy.  There is a nondisclosure agreement that I have to watch the terms of (which won't impact your use of this).  So, if you would drop me an email at esx@att.net then I'll send you back the details on what is needed to execute this plug in under Proteus.

And a general, comment to all:  I would "second" Guenther's and the other's comments that the best learning tools for the SX are the actual SX (and the SX-Key) and of course the SXSim.  These work really well when the SX is the center of your design/thinking/learning.   When the SX is one component among many then (IMHO) low-level emulators, and such tools, tend to become valuable because the interactions among the many components tend tp become very interesting (and perhaps hard to visualize).