pass a dimentional array(2D) to a function VHDL

Question

I declared a matrix and a signal in my TOP file like this:

type scanImage is array (0 to 7,0 to 7) of std_logic_vector(2 downto 0);
signal image_matrix : scanImage;

Now, I want to send the above signal to a function which calculates number of cells in the matrix which are not "000".

My package looks like this:

library IEEE;
use IEEE.std_logic_1164.all;
 use IEEE.std_logic_unsigned.all;
 use IEEE.std_logic_arith.all;
use IEEE.NUMERIC_STD.ALL;
 USE IEEE.NUMERIC_BIT.ALL;


PACKAGE my_pack IS

type double_array is array (0 to 7,0 to 7) of std_logic_vector(2 downto 0);

--------------------square calculation declaration--------------------------
 function square_calculation(matrix : double_array) return integer;


 ---------------------------------------------------------------------
 function square_calculation(matrix : double_array) return integer IS
 variable tmp: integer range 0 to 64;
 begin
  tmp:=0;
  for i in 0 to 7 loop

            for j in 0 to 7 loop
                if matrix(i,j)/="000" then
                    tmp:=tmp+1;
                end if;
            end loop;

end loop;
return tmp;

end function square_calculation;


 END my_pack;

After compilizing I get this error: Error (10476): VHDL error at vision_ctrl.vhd(112): type of identifier "image_matrix" does not agree with its usage as "double_array" type

Thanks for helping me.

** I must use the type declaration as above: type scanImage is array (0 to 7,0 to 7) of std_logic_vector(2 downto 0); can't use another way — axcelenator, Feb 08 '15 at 10:17
In my top I pass the matrix like that: square<=square_calculation(image_matrix); — axcelenator, Feb 08 '15 at 10:19

Morten Zilmer · Accepted Answer · 2015-02-08T14:53:53.643

3

The two arrays scanImage and double_array are not the same type; just happens to be declared the same way.

So declare image_matrix with the type double_array, instead of making a new type scanImage:

signal image_matrix : my_pack.double_array;

Then you can use my_pack.square_calculation with the image_matrix argument.

edited Feb 08 '15 at 14:53

answered Feb 08 '15 at 11:50

Morten Zilmer

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pass a dimentional array(2D) to a function VHDL

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