Disclaimer: This is only to alert you to something you might
want, and to give you some information which may save you wasting
time. I get nothing from either program's owner, so I'm not
triple checking each point made for accuracy. I hope it is of use
to you.. and if it isn't, it's worth what anyone paid me for my
work!
______
I've tried two shareware simulators of digital electronics. Each
is usable, each has shortcomings. I think either is suitable for
use in schools for 9 yo and up... but see below. Either would be
of some use to adults interested in digital electronics.
Installation, etc, of neither is as user friendly as it might be,
but hey!, they are shareware!! Do you want a simulator or not?
Using them is straightforward, once you get used to them. First
complaint: I couldn't find on-line contact channels for either.
______
They are:
Digital Simulator (DS) 1.0, by Ara Knaian in MA, USA
EasySim (ES) from Research Systems in Australia
I've run both on a Win98 machine.
DS is advertised as being for Win95. Registration is $20, US.
ES is a Win 3.x program, but runs on Win98, as I said.
Registration costs are given in Australian dollars: $A50, plus
they want $A15 for p&p to non-Australian addresses.
_______
Overview
Both give you a worksurface onto which you place digital
electronics elements by clicking on what you want from a
'palette', and then clicking on where you want it. Both offer
AND, OR, NOR, XOR, etc gates. Both have flipflops and latches and
7 segement LED displays. You then make connections between the
elements.
Both work in two modes: design mode and simulation mode. You set
up the circuit in design mode(DM). You then see what it does in
simulation mode(SM). In SM, you can change the state of inputs by
clicking on them. I liked DS's inclusion of toggle switches (stay
'0' or '1' after being clicked) and a momentary switch which
outputs a '1' only so long as you keep it 'pressed' with the
mouse. Clever: If you double click the switch it changes to
producing a '1' UNLESS you have it 'pressed'. Rough edge: There
is no difference in the icons for the two sorts of switch.
DS seemed much better on dynamic circuits, as far as I explored
the two packages. It has a square wave generator, with variable
frequency and duty cycle.
'Wiring' together the elements was quickly easy in ES, but not
hard in DS. ES has a nice 'logic trace' feature that highlights
any wire with a '1' in it (if you wish. Can be turned off.)
The good news... DS is cheaper than ES.
The bad news... it is more prone to crash. Annoying, confusing,
etc, for the less didicated/ confident user. It was also capable
of displaying things which looked wrong to me. Probably best used
in schools with teacher support. The more expensive, more
limited, ES I would happily provide to unsupervised 9yo. (I would
want to introduce them to it, but wouldn't feel they needed even
that.)
_______
How to get them...
I obtained Digital Simulator from PDSL (www.PDSL.com\, I think...
they have a site, but not a download site... you have to order by
snailmail) The Public Domain & Shareware Library, PO Box 131,
CROWBOROUGH, E Sussex, TN6 1WS, England, Telephone: 01892-663298
Fax: 01892-667473
Digital Simulator is their ref N005043
The program refers you to...
Ara Knaian, 38 Llewellyn Road, Newton, MA, 02165, USA,
(617)964-0299 (tell him about this review, please?)
- - - - -
I found EasySim by searching the ZDNet download archive for
Windows digital simulators. The download was only 91k.
If you click here, it might take you to the Ziff-Davis EasySim download page. Alternatively,
Click here to access the front page of Ziff Davis's excellent shareware archive/ search engine.
If you want to send some snailmail to EasySim's people.... (tell them about this review,
please?)... the address is:
Research Systems Pty. Ltd.
15/1540 Main Road,
Research,
Victoria 3095,
Australia.
___________
Fiddly bits... random thoughts, etc....
I had minor trouble with the installation of ES. Seemed to unzip,
but the 'files' were empty. Probably something to do with trying
to install to a folder which held the folder I had the zip file
in.
Neither offer rubber banded dragging of components.
DS doesn't even offer dragging at all... you have to cut, then
paste. On limited use, I found getting what I wanted marginally
easier with ES.
DS uses a green circle to say '0' and a red circle to say '1'..
for inputs and outputs. ES uses '0' and '1' to mark inputs, and a
'lamp' which is grey or yellow to display the state of outputs.
(I prefer the latter.)
DS offers a logic analyser... I didn't get it to work, but I
didn't try very hard! It is supposed to monitor multiple signals
and display state against time graphs. Pretty snazzy! Typical DS:
more ambitious. When the bugs are out, this is going to be a
great program, and the price is great, too.
Edited quote from a file which came with ES:
"EasySim is a digital electronics simulation package. It
allows digital circuit designs to be designed and tested in a
windows environment. It gives the user a selection of logic gates
and flip flops along with various input and output devices, thus
providing building blocks to emulate logic functions.
"The product is aimed mainly at the educational market but
will also be of value to the electronics enthusiasts wishing to
test out small circuits before committing themselves to wiring up
a circuit."
<end of quote>
Click here for information about another logic simulator, Virtual Workbench.
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