Proteus Error" Excess CPU load simulation cannot run in real time"

Anyone has come up with a solution of avoiding real time simulation problem in ISIS. I was making frequency counter using PIC18F452, it works fine in KHz range but gives error "Excess CPU load simulation cannot run in real time" in MHz range. I am working on Intel Core i7 2.2GHz with turbo boost upto 3.10 GHz.

Not being able to run Proteus simulations in real time is fairly typical, no matter how fast the host system.

To accomplish the task would require a high degree of concurrency, higher than available on a Quad Core and Windows based system.

You can use the simulation clock in the lower corner to track critical timings.


BigDog

Try to simplify the circuit as much as you can.
For example remove any dividers or filters from the input and use a square wave source directly to check your code.
Limit the analog circuitry to a minimum.
There is also a simulation setting that can be set for speed or accuracy.

Re: Proteus Error" Excess CPU load simulation cannot run in real time"

I think in real hardware it will work fine. Anyhow Labcenter Electronics should take notice on this problem.

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alexan_e said:

Try to simplify the circuit as much as you can.
For example remove any dividers or filters from the input and use a square wave source directly to check your code.
Limit the analog circuitry to a minimum.
There is also a simulation setting that can be set for speed or accuracy.

Click to expand...

My circuit only have PIC18f452 and clock source connected to RA4 (Timer 0). How to do the simulation settings?

Simulations of digital systems has always been a challenge, when the added complexity of analog systems is inserted into the simulation, it becomes extremely difficult to simulate the entire system in real time.

I'm afraid it is more of a limitation of the host system, then the simulation software.

Notice if real time simulations of digital hardware are required, they are typically implemented on a FPGA platform, not emulated on another processor/OS system.

As the clock/timing of system under simulation increases, the analysis time quanta decreases to a point it is no longer possible to simulate the multitude of simultaneous/concurrent events in the given quanta.

Therefore this is why a digital/analog mix system which can be simulated in "real time" in the kHz range, cannot be simulated in "real time" in the MHz range.


BigDog

Re: Proteus Error" Excess CPU load simulation cannot run in real time"

qwertyuiop415263 said:

How to do the simulation settings?

Click to expand...

Actually I'm not sure if it gives better speed but it gives better converge.
The setting is at system -> set simulation options.

alexan_e said:

Try to simplify the circuit as much as you can.
For example remove any dividers or filters from the input and use a square wave source directly to check your code.
Limit the analog circuitry to a minimum.
There is also a simulation setting that can be set for speed or accuracy.

Click to expand...

This really improved my simulation. I had a power supply circuit on the same schematic. I was testing TMR1 on interrupt buy turning a LED on and off after 2 seconds. I couldn't wait enough to see the LED goes on. I had the same error. The power supply had a step down transformer, rectifier diodes, big filter cap followed by 7805 regulator circuit. After reading this I just selected the power supply circuit and cut it from the circuit. Run the simulation with no other changes I saw the LED goes on and off, and the error didn't appear again. I is still slow. But it has shown me the effect of filters on the circuit. There are still two dividers, though. They are important for the simulation thus I couldn't remove them.