i have seen the proteus 8 working pretty good from the videos on the youtube.
but i need an alternative to it (open source).
primary thing i want to use this soft is for simulation .
i have checked the internet for best alternatives
here is the link i got.
http://alternativeto.net/softwar...
but all these soft lack simulation they are for schematic and pcb design
please suggest me appropriate soft
thanks 
but i need an alternative to it (open source).
Do you really mean Open Source - or do you just mean you want it for free (as in beer) ?
What, exactly, do you want to simulate?
Why do you need a simulator - when on-chip debug gives you full access to the real hardware?
Atmel Studio has a simulator for the AVR.
There are a number of free "SPICE"-like tools.
Pretty sure that some (most?) of the free offerings from the big distributors include simulation these days ...
http://www.lmgtfy.com?q=free+circuit+simulator
While Proteus offers general electronic circuit simulation the main reason people use it with AVR is that it also has a complete emulation of all the AVR CPUs and also many of the common peripherals you might attach to them. Is that what you are looking for? If so then I fear you are going to find that apart from the CPU simulations in Studio 7 and (to a lesser degree) the Simulavr simulator that is mainly used for Linux there is nothing that comes close to Proteus. (which is why they are able to charge £300 per copy as they know you don't really have an alternative).
To be honest though, in this world of $5 Arduinos in which we now live is it really that necessary. If you have an "idea" and want to try something out then it's probably just as easy to pick up a $5 Arduino and wire something up to it (assuming there isn't already a shield/library doing most of what you require anyway (and there will be!!)).
Unfortunately, the only programs I know with mixed analog/MCU simulation capabilities are Proteus and DesignSoft TINA (the full version, the free TINA-TI from Texas Instruments I think doesn't have MCU simulation, only analog - but you can feed it digital signals). Both are very expensive...
You can download the demonstration version of Proteus for free, and it is essentially the full program but without the ability to save your work/ projects. If all you're after is quick simulations of various pieces of circuit design to quickly see if an idea will work then that should do, you just have to live with not being able to save.
I want Proteus type simulator in which we can simulate mcu with feature of programming the MCU(coding)
simulate mcu with feature of programming the MCU(coding)
So isn't that what the Atmel Studio simulator gives you?
But as I said before, and clawson also suggested: is there really any point or benefit in simulating these days?
So isn't that what the Atmel Studio simulator gives you?
just CPU+internal peripheral simulation (which is what AS7 gives)
Which sounded to me like what the OP was asking for in #6:
simulate mcu with feature of programming the MCU(coding)
But who knows what he really wants?
@salmanma6 - clarification, please!
@salmanma6 - You also didn't answer the question about "open-source".
Which sounded to me like what the OP was asking for in #6: salmanma6 wrote: simulate mcu with feature of programming the MCU(coding)
Like I want to drive 7 segment displays and led matrices whose operation is dependent upon the MCU code.
I just want to see how it works.since it saves time
Like this- just an example
https://youtu.be/XHm5xQcCf9Q
I don't want to spend more money for a small basic student level project.
Open source-free ware
Want free soft
Surely you should persuade your University to buy Educational licences for Proteus.
I am sure that Labcenter has special arrangements for Universities.
.
As a hobbyist, I have thought about buying a Proteus licence. Then concluded that it is easier to just buy some cheap Arduino hardware from Ebay. Run any program on "the real thing".
.
David.
Thank you all for your suggestions.
Apart from Proteus the closest I have ever seen to anything like that for AVR that is "free" was an old project called "Hapsim". This was an "add-on" to AVR Studio 4 that did add things like 7 seg simulation to the AS4 simulator. However it was not an "official" add on but actually worked by hacking into the DLLs that AS4 used for simulation so it needed a new version to be released each time Atmel released a new copy of AS4. I think it might have been kept up to data as far as something like AS4.16 perhaps? You *might* still be able to find it.
Of course with such a thing there is no guarantee how good a simulation it is. For example it also offered to simulate UARt terminals and HD44780 LCD displays and for both the simulation did not actually care what timing the signals to it had. So you could set a spurious UART baud rate or drive the LCD signals with any timing and the thing would still appear to work. Yet if you took the same code to real hardware it would fail because the timing was wrong. Again Proteus simulates all this correctly and even displays warning windows like "you are driving the LCD "E" signal too quickly" or whatever. Again this is why Proteus costs £300!
So if you want to do this "cheap" then you could try and find an old version of AS4 and a copy of Hapsim but you may find you spend more times working out what are the bugs in the simulation rather than bugs in your own electronics or software.
As we've all said, now you can get Arduino for $5 then you can actually do this "for real" so there's little merit in trying to simulate it these days. I suppose the one thing an Arduino may not offer is CPU visible debugging - though there are solutions for that too.
EDIT: OK, just visited http://www.helmix.at/hapsim/ and it says it works right up to the very last issued version of AS4 (that is 4.19) so there may be some merit in looking at that after all - I think Atmel still have 4.19 for download somewhere.
(don't see 7-seg there but there is "LED simulator" so you could presumably fake a 7seg as 7/8 LEDs ?)
Like I want to drive 7 segment displays and led matrices whose operation is dependent upon the MCU code. I just want to see how it works.since it saves time Like this- just an example https://youtu.be/XHm5xQcCf9Q I don't want to spend more money for a small basic student level project. Open source-free ware Want free soft
You want to know how it works? It works well, it's a great program. It's quite complex, though. Btw, I'm pretty sure most of these guys in Youtube vids are running the pirate versions, I don't think all those people have paid hundreds of $$$...
They give the wrong impression that the program is easily available, inducing people in error.
Go to this site by Autodesk https://circuits.io where you can do a whole bunch of simulation online. You have to poke around to select the right "hub" but it does the job for me.
I am sure that Labcenter has special arrangements for Universities.
They do indeed.
@salmanma6 since you basically want the capability of Proteus but for free, I'm going to once again point to the demo version. As I said in post #5 the demo version is
the full program but without the ability to save your work/ projects
As far as the code goes that shouldn't matter since you'd be using a separate IDE for that and you'd just import the code (and possibly a binary) into the project and click go, the only thing that could be a pain is you'd have to draw the circuit again every time you closed Proteus. However you would essentially be getting the latest version of Proteus for free that way, I myself do this but only with circuit design since it can help with proof of concept.
At the end of the day, as has already been mentioned many times on this thread, Proteus is very very good, but you get what you pay for. In short, you aren't going to get something as good a Proteus without paying for something as good as Proteus.
Be warned though, there are a fair few threads on 'freaks where people have simulated their projects on Proteus to the moon and back, then when they get the real hardware it doesn't work (even though it did in the Proteus simulation). Nothing beats the real deal, which is where Cliff's suggestion of simply using an Arduino holds a lot of merit.
Howard thanks! I never realised there was a trial version available. Will have to "play". As you say one could build elsewhere though I guess the simulated circuit can't be too complex if you have to reconstruct it each time?
I guess it depends on how complex a circuit you mind re-drawing! Obviously the more complex it is the more chance there is of you drawing part of it differently causing it to behave differently. I suppose you could take a screen shot so you know which components you used and how you wired everything up, or you could simply not turn off your PC and leave Proteus running for as long as needed? Though depending on what you have running in the background (anti-virus etc) you may find the cache fills up leaving Proteus running like a donkey...
Way off the planet idea.... buy an old clunker for less than GBP300 and keep it running with your unsaved application. 
Run in a virtual machine and take a snapshot... nah, that's crazy...
LT spice is a popular choise for simulation, It's free (as in beer) but not open source.
It has a good reputation for usability/accuracy, but unfortunately it's GUI is not very intuitive (for my head at least).
http://www.linear.com/designtool...
There has also been a lot of work being done to integrate Spice into KiCad.
KiCad is quite a decent open source schematic / PCB Design suite and getting better all the time.
Spice simulation is not yet in the stable release, but it seems to be already usable in the development snapshots.
https://duckduckgo.com/html?q=Ki...
And version 5 of KiCad is expected to be released somewhere this summer and according to it's roadmap spice integration is already complete.
