multisim rom memory

[laProfe]

I want to create a simple circuit with a memory ROM 27c64 with a content inside.

The circuit do not have MCU units.

Is it posible to edit the content of the memory and simulate it?

Whith the circuit in the attach I would like generate a sinusoidal wave form.

But I don't know how to write the 256 values of one cicle on the sinsoide inside the ROM.

[nestor-sg]

Unfortunately, those memory units are designed to work with MCUs such as the PIC, not by themselves alone. If you can write a MCU program that will write to the memory you could probably interface. Look in the examples folder in Multisim under the MCU folder there is a program for RAMController (under the 805x folder)... try that one.

[laProfe]

I made a progress.

I initiate the simulation of the circuit then I put it in PAUSE mode. When in PAUSE manually  I insert  one by one 256 values  of a sine wave inside the memory. Then I put it in RUN mode.  It work well. I could not save the content of the memory. I have simulated digital circuits with ISE(XILINX) and QUARTUS(ALTERA) , both  let  you add files .coe or .mif with the content of the memories.  I think that  it is an upgrade that must be add to EWB.  

In the attach you will find a demostration of my progress.

[lacy]

What laProfe has found here is real interesting. In my opinion that would make the MCU Module even more versatile. 

[nestor-sg]

Yep, that is correct, the memory view of the MCU Module allows you to manually change memory addresses for 'debugging' purposes when a simulation is paused (or you placed a breakpoint on your source code).

The only memory that allows you to add a file with the HEX data is the EEPROM (internal of the MCU), ROM and RAM are usually programmed by the MCU.

What laProfe (la profesora?) is doing is exactly that, pausing a simulation and manually tweaking those memory addresses, the problem with this is that it is not designed for this, therefore it might become somehow annoying in the future to do it this way.

I will talk to the R&D engineer who developed the MCU module and point out how users like laProfe would like to use those memories.

Thanks laProfe for sharing with us your findings.

[laProfe]

At this moment I am evaluating the use of EWB in my course EC1723 Digital Electronics at USB Caracas Venezuela.

My course begins in september.

The EWB simulate a circuit with a ROM or RAM with a content inserted manually in debug mode. It seems to me that it could be easy modify the EWB in a way that it let add a file(INTEL .hex or  XILINX .coe or ALTERA .mif or EXCEL csv..) with the content of the memory and simulate it.

Thanks to Nestor for talking to the  EWB R&D personnel.

laProfe

[zhangjianwu]

Thank laProfe. I am searching the solution to preset data in EEROM too.

Your solution do help me a lot.

And I hope NI could provide a more powerful tool to set the data of ROM.

[coocoo]

I am looking forward this feature...

Though nearly 2 years passed...

[angilberto]

I´ve used this workaround:

Add a 74154 decoder/mux to your project pretending its a ROM (64x16). Now open and modify its model data. See example attached...

Angilberto.

[jcfubc]

Maybe it is a bit late now, but here is a possible solution based on the suggestion of angilberto. I created a new component (ROM_256x8) and wrote a C program to create its digital model.  The model has a table with 256 rows.  Each row in the part model represents the digital value of the analog sine wave.  Attached are the Multisim project and the C file.  This is the result of the simulation: