On May 30, 9:47=A0am, KJ <kkjenni...@[EMAIL PROTECTED]
> wrote:
> On May 30, 12:16=A0pm, Shannon <sgo...@[EMAIL PROTECTED]
> wrote:
>
>
>
>
>
> > I've been searching here but all the hits were for converting SLV to
> > string for testbenches.
>
> > I'm looking to convert a string to an array of 8bit SLVs. =A0The idea
is=
> > I have a revision string of fixed length- something like:
>
> > ver <=3D "005-0805300908x2"'
>
> > and I have an array of registers declared as such:
>
> > SUBTYPE hwid_type is STD_LOGIC_VECTOR(7 DOWNTO 0);
> > TYPE reg_type IS ARRAY (0 TO NUM_REGS-1) OF hwid_type;
> > SIGNAL =A0regs : reg_type;
>
> > What I'm looking for is a loop shown here in psuedo code:
>
> > for i in 1 to 16 loop
> > =A0 =A0 regs(i) <=3D to_slv(ver(mid$(i,1)))
> > end loop
>
> > Note this is for synthesis so I don't know if any of this is even
> > legal. =A0I am trying to create a version register that the
> > microprocessor can read. =A0An ascii string is prefered - let's
pretend
> > for a moment it is a requirement. =A0This is also a learning exercise
> > for me to deal with strings in VHDL.
>
> > Any ideas?
>
> > Shannon
>
> Since your input string has some non-numeric characters in it that you
> presumably want to keep in the string, then the best approach would be
> to simply write a function that parses the string however you'd like.
>
> Below is an example that simply adds the 'value' of each input
> character to produce an integer output. =A0You should be able to easily
> modify this to select out whichever characters you want and perform
> whatever calculations you'd like.
>
> function Version_String_To_integer(Some_String: STRING) return integer
> is
> variable Return_Value: integer :=3D 0;
> begin
> for i in Some_String'range loop
> =A0 Some_Char :=3D Some_String(i)
> =A0 case Some_Char is
> =A0 =A0 =A0when "0" =3D> Return_Value :=3D Return_Value + 0;
> =A0 =A0 =A0when "1" =3D> Return_Value :=3D Return_Value + 1;
> =A0 =A0 =A0...
> =A0 =A0 =A0when others =3D> null;
> =A0 end case;
> end loop;
> return(Return_Value);
> end function Version_String_To_integer;
>
> KJ- Hide quoted text -
>
> - Show quoted text -
As I suspected. So to flesh things out a bit....
function Version_Char_To_slv(Some_Char: character) return slv
is
variable Return_Value: slv(7 downto 0) :=3D (others =3D> 0);
begin
case Some_Char is
when "0" =3D> Return_Value :=3D STD_LOGIC_VECTOR(TO_UNSIGNED(0,8);
when "1" =3D> Return_Value :=3D STD_LOGIC_VECTOR(TO_UNSIGNED(1,8);
...
when "a" =3D> Return_Value :=3D STD_LOGIC_VECTOR(TO_UNSIGNED(97,8);
...
when "-" =3D> Return_Value :=3D STD_LOGIC_VECTOR(TO_UNSIGNED(45,8);
...
when others =3D> null;
end case;
return(Return_Value);
end function Version_Char_To_slv;
and then back in my main process....
for i in 1 upto 16 loop
regs(i) <=3D Version_Char_To_slv(ver(i));
end loop;
Or something like that?
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