Howdy - I'm just getting started with FPGAs. In college I remember we used ModelSim with ISE for FPGA simulation. We were able to get a license through our school for free. Like a fool I no longer have that license, so what free options are out there? I saw that there is something called ModelSim Xilinx Edition III Starter
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I can't tell if that is just a limited feature package, or a time limited package. Is that what I want? Or is there something else I should be looking at?
The ModelSim starter is limited. I think the main limitation is that it is programmed to get radically slower as the number of lines of HDL increases. -Kevin
Hi Hans - thanks for the information. I'm not terribly worried about speed at the moment - I'm just trying to learn the basics for now. Do you know how the student edition
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compares to these? It can't handle mixed HDL designs which seems a bit of a handicap - but I can work around that. I couldn't find any mention of a limit on speed or the number of executable lines.
Also - is there a Xilinx simulator that is built into ISE? I am following a Xilinx tutorial
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and it first says "Whether you use the ModelSim simulator or the ISE Simulator with this tutorial, you will achieve the same results." suggesting there is a fully functional tutorial built into ISE, and then two paragraphs down it says "In order to use this tutorial, you must install ModelSim on your computer.". So that just confused me.
The most recent version of ISIM (the ISE simulator) is much faster and has a new parser so it supports the language(s) much better. The user interface is a bit coarser and the waveform viewer is not as nice as Modelsim's, but it might work well for you. I didn't consider this because it's not really free, since ISE isn't free, but if you already have ISE it might be a good option. -Kevin
I'm confused - I just downloaded the "ISE WebPACK 9.2i" a couple days ago and didn't pay a thing. (and it never asked me to pay a thing). Does this have a built in simulator, or is it only the version that you pay for that has a built in simulator? Thanks,
I believe it is the same speed as PE but I am not 100% sure.
I agree, some companies (I don't want to mention any names
*cough*Micron*cough*) decided to only provide models in one language forcing users to spend extra money on a dual language license, perhaps they are sponsored by the EDA industry? :-)
For behavioral sim you could go with a brand agnostic tool like ghdl and iverilog are both free, and I've used them sucessfully for simple to quite large designs. I find the Xilinx and Altera tools to be too slow and cumbersome, but I haven't compared those sim tools to ghdl or iverilog.
Basically you write your test bench in the same language as a module that uses your hardware module, but does not have to be synthesizable and can use all those extra language pragmas like $monitor(), $fprintf(), $system(), etc. It is also easy to pipe the data into/out of the testbench for external processing and verification. Waveforms can be viewed with gtkwave.
taken from
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and
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--------------------------- test.v--------------------------------------------------------------------------------------- module test_fixture; reg clock100 = 0 ; reg latch = 0; reg dec = 0; reg [3:0] in = 4'b0101; wire zero; initial //following block executed only once begin $monitor("%b", u1.value); $dumpfile("count.vcd"); // waveforms in this file.. //$dumpvars; // saves all waveforms #16 latch = 1; // wait 16 ns #10 latch = 0; // wait 10 ns #10 dec = 1; #100 $finish; //finished with simulation end always #5 clock100 = ~clock100; // 10ns clock
/*----------------Nets and Registers----------------*/ /*---(See input and output for unexplained variables)---*/
reg [3:0] value; /* current count value */ wire zero;
// Count Flip-flops with input multiplexor always@(posedge clock) begin // begin-end not actually need here as there is only one statement if (latch) value > >> used ModelSim with ISE for FPGA simulation. We were able to get a
----------------------------------------------------- ISE WebPACK 9.2i does not include the HDL simulator. Therefore, you need to install it (ModelSIM XE) separately. There is a WebPack10.1 now, but I haven't check it if it also include the simulator.
Hi - I do have the three exes Kevin mentioned (vlogcomp.exe, vhpcomp.exe, and fuse.exe) - so I'm assuming that means I have it? Is there a way to quickly test run it?
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