Cannot initialize a 2-D array of bytes from file directly (ram_init_file / $readmemh)

Altera_Forum · ‎05-15-2016

Hello forum Members,

I have been experimenting with file-based initialization of Verilog multidimensional arrays.

Until now i succeeded initializing with the help of flat temp. array

------------------------------------------------------------------------


reg  charMem;
reg  colMem;
reg  charMemTmp;
reg  colMemTmp;
initial
begin
 $readmemh("DE0_CV_SCREENCHAR.txt",charMemTmp);
 $readmemh("DE0_CV_SCREENCOL.txt" ,colMemTmp);
 $readmemh("DE0_CV_SCREENPAL.txt" ,palMem);
 end

and

always @(posedge CLOCK_50)
begin
 if (~RESET_N)
 begin
  integer row;
  integer kol;
  for (row=0;row<25;row++)
  begin
   for (kol=0;kol<80;kol++)
   begin
    charMem=charMemTmp;
    colMem=colMemTmp;   
   end 
  end
 end
end

=> This works fine, i use a flat helper array read in the data and copy everything to a 2-d array.

However if i try to read it directly:

-------------------------------------

reg  charMem;
reg  colMem;
initial
begin
 $readmemh("DE0_CV_SCREENCHAR.txt",charMem);
 $readmemh("DE0_CV_SCREENCOL.txt" ,colMem);
 $readmemh("DE0_CV_SCREENPAL.txt" ,palMem);
end

=> I get: "10853 verilog HDL error ... : argument 1 to $readmemh must be a memory identifier ???

I also tried reading from a .mif file (1d file 2000 x 1 byte Width=8 depth=2000):

-------------------------------------

(* ram_init_file = "DE0_CV_SCREENCHARMEM.mif" *)  reg  charMem;
(* ram_init_file = "DE0_CV_SCREENCOLORMEM.mif" *) reg  colorMem

;

=> this works fine

Does anybody know how to initialize the 2-d array from a file using ram_init_file or $readmemh ?

I a using Quartus 15.1 on Win7.

Thanks in advance,

Johi.

Update:

I have a hunch (from debgging the .mif files generated by quartus from the .txt initialization files that depth needs to be 25 and widt 640 = 8*80

I will try this and come with an update.

Johi.

Altera_Forum · ‎05-16-2016

Conclusion:

initializing a 2 d array using a .mif file works for a 2d array:

Example:


// char mem
/*(* ram_init_file = "DE0_CV_SCREENCHAR.mif" *)*/ reg  charMem;
// color mem
(* ram_init_file = "DE0_CV_SCREENCOL.mif" *) reg  colMem;
// color mem
(* ram_init_file = "DE0_CV_SCREENPAL.mif" *) reg  palMem

I added the .mif files for these initializations.

initializing a 1 d array also works.

// helper variabeles to read .txt file:

reg [7:0] charMemTmp[2000];

reg [7:0] colMemTmp[2000];

reg [3:0] palMemTmp[48];

//--------------------------------------------------------
// initialize char memory (this statement will be synthetisised):
initial
begin
    $readmemh("DE0_CV_SCREENCHAR.txt",charMemTmp);
    $readmemh("DE0_CV_SCREENCOL.txt" ,colMemTmp);
    $readmemh("DE0_CV_SCREENPAL.txt" ,palMemTmp);   
end

In the zip file, all .mif and .txt are included. And also a .XLS with macro's to generate these files.

Best Regards,

Johi.

rramo10 · ‎12-28-2018

Thank you for sharing!