reading a file in testbench(verilog)

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param

Joined: 09 Sep 2005
Posts: 46
Helped: 4

10 Mar 2006 10:25 verilog fread

hi all,
how to assign the input data written in a file to the port, for testbench purpose using verilog hdl?
suppose i have some samples of input data written in .dat file,
and in my testbench i want to input all the values written in that file, how can i do it?
i have tried in the below manner and could not find any data assigned to the input pin while simulating,

data_in = $fopen('' input.dat","r");

please help to solve this.........

vivek

Joined: 19 May 2005
Posts: 69
Helped: 9

10 Mar 2006 11:21 verilog read file

$fopen will only open the file. To do any file operation in verilog this has to be done first. for reading from file try $memreadb (for binary files) or $memreadh (for hex files).

eg :

Code:

reg [7:0] mem[1027:0];
......
initial
begin
$readmemb("file_name",mem);
end

U also have $fscanf, $fgetc, $fread to read files. Not sure abt the exact syntax for their usage, but should be similar to above one.

darylz

Joined: 24 Mar 2005
Posts: 132
Helped: 4

10 Mar 2006 12:33 verilog read from file

system command

nand_gates

Joined: 19 Jul 2004
Posts: 907
Helped: 120

10 Mar 2006 13:12 verilog file read

Here is the example ur looking for .....
Hope this helps

Code:

module stim_gen (
// Outputs
clk, data
);
output clk;
output [7:0] data;
reg clk;
reg [7:0] data;
integer fd;
integer code, dummy;
reg [8*10:1] str;

initial begin
fd = $fopen("_input.dat","r");
clk = 0;
data = 0;
code = 1;
$monitor("data = %x", data);
while (code) begin
code = $fgets(str, fd);
dummy = $sscanf(str, "%x", data);
@(posedge clk);
end
$finish;
end // initial begin
always #5 clk = ~clk;
endmodule // stim_gen

Contents of _input.dat file

Code:

0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7

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10 Mar 2006 13:12 Ads

banjo

Joined: 24 Dec 2005
Posts: 644
Helped: 118

10 Mar 2006 13:58 reading a file in verilog

FYI,

If you want to process binary data, this can be tricky readmemb did not work for me when I needed to do this. I finally ended up using:

file = $fopen("code.vec", "r");

return_value = $fread( mem, file);
if (return_value !=1)
error = 1;
else
..............

"mem" is an eight bit varible. When the return_value is not 1, then the read failed and you are at the end of the file.

--- Steve