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Memory Initialization: mif, coe, hex, etc,

Hi experts,

I've looked through the archives, and the Xilinx literature, and haven't found an answer to this question, so please forgive me if it's obvious and/or everyone's sick of answering. I've spent a couple of days on this.

I'm upgrading a lab here at UVic from an xc4000 based board to a Spartan2. So as not to complicate the upgrade needlessly, we'd like to stick with Foundation 4.2i tools and design flow. (We'll upgrade that next semester.. one thing at a time.) The students are to create a pipelined 8-bit processor in either VHDL or Schematic. They use the Foundation simulator to debug.

The first issue I came up against was that they now have to use CoreGen to make memories (program, data, stack), where we used to use LogicBlox. Specifying memory contents in LogicBlox used a .mem file. In Coregen, you have to use a .coe file. Easy enough, and when I go all the way through implementation, I have no problems at all.

When I want to do a functional simulation, however, the program memory is all zeroes. How best to go about getting the .coe data into the Foundation functional simulator? The VHDL and verilog files reference a .mif file. The simulator allows one to "load contents" via a hex file.

I'd prefer a solution that only requires students to edit one file to change the program for both the hardware implementation (I've noticed that CoreGen puts the correct data in the EDIF file) AND the simulation. It's a pretty challenging lab as it is, without the extra pitfall of having mismatching simulation/hardware programs.

Thanks for your time,

JP

--
                Josh Pfrimmer, B.Eng.
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 University of Victoria, ECE
 jpfrimmereceuvicca
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->My views and opinions are not necessarily UVic's
Reply to
Josh Pfrimmer
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Consider using a vector array to infer rom or ram and eliminate the coregen simulation hassles.

-- Mike Treseler

Reply to
Mike Treseler

could do. How are the Xilinx 4.2 tools at inferring BlockRAM vs. Distributed RAM? Are they efficient?

In the interest of fully exploring the issue, though (though I may very well take your suggestion) How do people cope with the problem below, when CoreGen _is_ used?

JP

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Reply to
Josh Pfrimmer

For similar situation, I had a script that translates assembly instructions directly to .coe and .mif files and edits the ram initialization in the .edf. In the case of a single block ram, the edit of .edf is quite trivial. If you need more than one block, the words will be distributed between the rams, which complicates the script a bit, but is also quite doable.

On the other hand, regenerating the .edf is just one click in CoreGen.

--
T.Rissa
tpr at doc ic ac uk
Reply to
Tero Rissa

instructions

.edf.

Sure, but the functional simulator in Foundation doesn't read the coe, mif, or edf file. I'm hoping to find the best possible way to allow the students to change their program and have those changes show up in both simulation and hardware.

JP

Reply to
Josh Pfrimmer

Maybe this would be a good introduction to tools-in-real-life?

Can you kludge together something to push the info in those files into some place/form where the simulator will see it?

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Reply to
Hal Murray

Hi,

In xilinx coregen generate a .coe file with the memory editor (found in the tool menu) with the correct depth an width for the memory you want. This will give you a .coe and a .mif file. Then generate your memory with coregen. Go to the last page of the configuration (for a dual port block memory for virtex pro it is page 4); there you select "load init file" , push on the button "load file" and fill in the name of the .coe file you generated before. Look in the generated VHDL file, the name of the .mif file in the VHDL file should match the file generated by the memory editor. For the Simulation put a .mif file with the correct content in your simulation directory. Your Simulator should read the .mif file via textio.

Robert

Reply to
Robert Baumgartner

Or use an array of constants for ease of simulation, and let synthesis handle the rom details.

-- Mike Treseler

Reply to
Mike Treseler

Followup to: By author: "Josh Pfrimmer" In newsgroup: comp.arch.fpga

I usually find these kinds of situations are excellent excuses to write a couple of Perl scripts.

Oh yes, am I the only one who thinks it's somewhat bizarre that almost none of these tools can deal with a plain old binary file?

-hpa

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Reply to
H. Peter Anvin

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