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Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
20 years ago

Nios sim with Modelsim for LCD and DMA

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***** Sorry I posted this twice, I meant to post in software discussion board*********

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Hello,

I am trying to run nios sim to test a new LCD module. I have included a DMA as part of this system. I have defined an array an a pointer to

that array as below:

unsigned short lcd_frame_buffer[HORZ_PIX * VERT_PIX];

int main(void)

.

.

.

uncached_buffer = (unsigned short *)(alt_remap_uncached( (void *)(main_frame_buffer), (alt_u32)(HORZ_PIX * VERT_PIX)));

My question is how and where do I initialize this data for a Modelsim simulaiton? I know that the array gets allocated memory in the .bss portion of the data code, but this is supposed to be zero initialization, right? I want to make a small perl script that initalizes

the sram_comp_laneX.data files used by modelsim, intializing memory from the C code takes too long.

But I am unsure where to initialize, the .bss portion or the stack?

Any tips greatly appreciated.

Thanks,

-Ray

1 Reply

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

    Hello all,

    I figured this out with a few tips from Altera. The declaration of the array and the decalred pointer create a buffer in the .bss portion

    of the code. So I just enabled a object dump file to correlate where my main buffer is located. I then wrote a small perl script to generate some bogus vectors that I would concatenate with the program .dat files. It seems to work okay.

    Just thought this post might save someone some time if they go with the Nios sim route:

    Here is the script:

    *****************************************

    # Open Outfile# Create video memory for simualtion# Then paste to Prog .DAT file# <main_frame_buffer> = Hex 40e200/ 4 = 3880 ( Because we have 4 byte lanes) = Dec 14464# So Make $mem_depth = Hex 3880 + Hex 75300 = Hex 78B80 = Dec 494464# Dec 480_000 = Hex 75300

    my $out_3_FH;

    open($out_3_FH, ">sram_prog_buff_1_lane3.dat") || die "Cannot open data:";

    my $out_2_FH;

    open($out_2_FH, ">sram_prog_buff_1_lane2.dat") || die "Cannot open data:";

    my $out_1_FH;

    open($out_1_FH, ">sram_prog_buff_1_lane1.dat") || die "Cannot open data:";

    my $out_0_FH;

    open($out_0_FH, ">sram_prog_buff_1_lane0.dat") || die "Cannot open data:";

    my $mem_depth = 494464;

    for($mem_addr = 14464; $mem_addr < $mem_depth; $mem_addr++)

    {

    my $out_pixel_at = "@";

    my $pixel_data = " AA\n";

    my $hex_mem_addr = sprintf("%08X",$mem_addr);

    my $mem_pixel = $out_pixel_at . $hex_mem_addr . $pixel_data;

    print{ $out_3_FH } $mem_pixel;

    }

    for($mem_addr = 14464; $mem_addr < $mem_depth; $mem_addr++)

    {

    my $out_pixel_at = "@";

    my $pixel_data = " BB\n";

    my $hex_mem_addr = sprintf("%08X",$mem_addr);

    my $mem_pixel = $out_pixel_at . $hex_mem_addr . $pixel_data;

    print{ $out_2_FH } $mem_pixel;

    }

    for($mem_addr = 14464; $mem_addr < $mem_depth; $mem_addr++)

    {

    my $out_pixel_at = "@";

    my $pixel_data = " CC\n";

    my $hex_mem_addr = sprintf("%08X",$mem_addr);

    my $mem_pixel = $out_pixel_at . $hex_mem_addr . $pixel_data;

    print{ $out_1_FH } $mem_pixel;

    }

    for($mem_addr = 14464; $mem_addr < $mem_depth; $mem_addr++)

    {

    my $out_pixel_at = "@";

    my $pixel_data = " DD\n";

    my $hex_mem_addr = sprintf("%08X",$mem_addr);

    my $mem_pixel = $out_pixel_at . $hex_mem_addr . $pixel_data;

    print{ $out_0_FH } $mem_pixel;

    }

    exit 0

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    -Ray