to_stdlogicvector ERROR

[sebs]

Hey,

I have a unsigned to std_logic_vector conversion and I get the
following error:

"to_stdLogicVector can not have such operands in this context."

I'm using Xilinx EDK 8.1

Here is some of my code to explain where the errror occurs.

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

M_ABus : out std_logic_vector(0 to 31);


signal row_cnt : unsigned(0 to 9);
signal row_cnt_en : std_logic;
signal row_rst : std_logic;


addr_counter : process(PLB_Clk, PLB_Rst)
begin
if PLB_Clk'event and PLB_Clk = '1' then
if row_cnt_en = '1' then
row_cnt <= row_cnt + 1;
end if;
end if;
if (PLB_RST or row_rst) = '1' then
row_cnt <= (others => '0'); -- 768-1
end if;
end process;

M_ABus(11 to 20) <= to_stdLogicVector(row_cnt); -- the error
occurs in this line.

Hope someone can help me with this.

Sebastian

 

[Brian Drummond]

On Tue, 11 Nov 2008 04:11:09 -0800 (PST), sebs
<sebastian.schueppel@googlemail.com> wrote:

Hey,

I have a unsigned to std_logic_vector conversion and I get the
following error:

"to_stdLogicVector can not have such operands in this context."

I'm using Xilinx EDK 8.1

Here is some of my code to explain where the errror occurs.

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

M_ABus : out std_logic_vector(0 to 31);
signal row_cnt : unsigned(0 to 9);

M_ABus(11 to 20) <= to_stdLogicVector(row_cnt); -- the error
occurs in this line.

I don't know what to_stdLogicVector does, but it doesn't convert from
unsigned to std_logic_vector.

Fortunately they are compatible types so no conversion is necessary, a
simple cast will do.

M_ABus(11 to 20) <= stdLogicVector(row_cnt);

- Brian

 

On Nov 11, 7:11 am, sebs <sebastian.schuep...@googlemail.com> wrote:

Hey,

I have a unsigned to std_logic_vector conversion and I get the
following error:

"to_stdLogicVector can not have such operands in this context."

I'm using Xilinx EDK 8.1

Here is some of my code to explain where the errror occurs.

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

  M_ABus     : out std_logic_vector(0 to 31);

 signal row_cnt      : unsigned(0 to 9);
 signal row_cnt_en   : std_logic;
 signal row_rst      : std_logic;

addr_counter : process(PLB_Clk, PLB_Rst)
 begin
   if PLB_Clk'event and PLB_Clk = '1' then
     if row_cnt_en = '1' then
       row_cnt <= row_cnt + 1;
     end if;
   end if;
   if (PLB_RST or row_rst) = '1' then
     row_cnt <= (others => '0');   -- 768-1
   end if;
 end process;

  M_ABus(11 to 20) <= to_stdLogicVector(row_cnt);   -- the error
occurs in this line.

Hope someone can help me with this.

Sebastian

The function To_StdLogicVector() is defined for BIT_VECTOR, and
STD_ULOGIC_VECTOR only. But you're passing it an UNSIGNED. Even
though STD_UNLOGIC_VECTOR smells kind of like an UNSIGNED, it's a
different type. However, the element types of std_logic_vector and
unsigned are both std_logic though, so you could just pass them
element by element:

for i in 11 to 20 generate
m_ABus(i) <= row_cnt(i-11);
end generate;

I might be missing some obvious library conversion function, on the
other hand :-(

- Kenn

 

[KJ]

On Nov 11, 7:11 am, sebs <sebastian.schuep...@googlemail.com> wrote:

Hope someone can help me with this.

M_ABus(11 to 20) <= std_logic_vector(row_cnt);

KJ

 

[sebs]

On 11 Nov., 13:58, KJ <kkjenni...@sbcglobal.net> wrote:

On Nov 11, 7:11 am, sebs <sebastian.schuep...@googlemail.com> wrote:

Hope someone can help me with this.

M_ABus(11 to 20) <= std_logic_vector(row_cnt);

KJ

Thanks KJ that works

@Kenn

To_stdlogicvector is defined in ieee.numeric_std.all as

function TO_STDLOGICVECTOR ( ARG: UNSIGNED) return STD_LOGIC_VECTOR;
-- Result subtype: STD_LOGIC_VECTOR, same range as input ARG
-- Result: Converts UNSIGNED to STD_LOGIC_VECTOR.

 

[KJ]

On Nov 11, 8:02 am, sebs <sebastian.schuep...@googlemail.com> wrote:

To_stdlogicvector is defined in ieee.numeric_std.all  as

 function TO_STDLOGICVECTOR ( ARG: UNSIGNED) return STD_LOGIC_VECTOR;
     -- Result subtype: STD_LOGIC_VECTOR, same range as input ARG
     -- Result: Converts UNSIGNED to STD_LOGIC_VECTOR.

You might want to check your source that you got numeric_std from.
The to_stdlogicvector type conversion function was removed from the
final version of the IEEE standard in 1993.

KJ

 

On Nov 11, 8:02 am, sebs <sebastian.schuep...@googlemail.com> wrote:

@Kenn

To_stdlogicvector is defined in ieee.numeric_std.all  as

 function TO_STDLOGICVECTOR ( ARG: UNSIGNED) return STD_LOGIC_VECTOR;
     -- Result subtype: STD_LOGIC_VECTOR, same range as input ARG
     -- Result: Converts UNSIGNED to STD_LOGIC_VECTOR.

OK, I'll embarrass myself publicly and ask where (in what version,
from what web documentation, etc) that's defined. I was admittedly
looking at a very old numeric_std, but I still don't see it in the
200x packages at vhdl.org nor in my (admittedly old) tool copies.

And what am I missing here? If that function really is defined and is
visible as stated, then why doesn't the OP's code work?

I'm feeling like I'm starting to imagine things here...

- Kenn