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Altera_Forum's avatar
Altera_Forum
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16 years ago

Memory Initialization File for multiple RAMs

Hi,

I'm new to FPGA development and maybe this question is simple, but I couldn't find an answer yet.

I am developing a system with multiple M4K memories which are instatiated inside a generate block over a genvar loop (I'm using Verilog and a Stratix II). For simulation I need them to be initialized with different data. I can specifiy a Memory Initialization File in the MegaWizard but this will initialize all memories with the same data. Is there an easy way to specify a different .mif for each memory?

5 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    yes, slightly edit the generated file, and add a parameter to it.

    Then assign a different string to that parameter each time you instanciate it in the for loop.
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    after the memory instantiation add:

    defparam ram_inst.altsyncram_component.init_file = "your_file_here.mif";
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Ok I got it so far. I am using the M4K memory within an other design unit. Here is the simplified code: 

    module LocalMem(...);
parameter cpuid = 0;
M4K memory (
    .clock(clk),
    .data(m4k_data),
    .rdaddress(m4k_rdaddress),
    .wraddress(m4k_wraddress),
    .wren(m4k_wren),
    .q(m4k_q)
    );
defparam memory.altsyncram_component.init_file = {"mem", cpuid, ".mif"};
endmodule
module TestLocalMem(...);
LocalMem# (.cpuid(1)) localmem_inst(...);
endmodule
    This does not work. Within the defparam line, cpuid seems to be empty. No matter what I set cpuid to, the file "mem.mif" gets loaded. I have also tried this to make cpuid the correct ASCII value: 

    defparam memory.altsyncram_component.init_file = {"mem", 8'd48 + cpuid, ".mif"};
    but no change...

    Maybe you have another hint for me?
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    I found a solution :)

    In case someone has the same problem here is my solution:

    To have a parameter concatenated with a string, it needs to represent the number's ASCII value. Therefore 48 needs to be added to its value. An other thing has to be considered: all chars in a string are represented as 8-bit numbers, therefore the parameter has to be 8 bits wide: 

    parameter  cpuid = 0;
    and 

    defparam memory.altsyncram_component.init_file = {"mem", 8'd48 + cpuid, ".mif"};
    fixed my problem :)