I need to get the values of several signals to check them against the simulation (the simulation is in Matlab). There are many values, and I want to get them in a file so that I could run it in a script and avoid copying the values by hand.
Is there a way to automatically print the values of several signals into a text file?
(The design is implemented in VHDL)
First make functions that convert std_logic
and std_logic_vector
to
string
like:
function to_bstring(sl : std_logic) return string is
variable sl_str_v : string(1 to 3); -- std_logic image with quotes around
begin
sl_str_v := std_logic'image(sl);
return "" & sl_str_v(2); -- "" & character to get string
end function;
function to_bstring(slv : std_logic_vector) return string is
alias slv_norm : std_logic_vector(1 to slv'length) is slv;
variable sl_str_v : string(1 to 1); -- String of std_logic
variable res_v : string(1 to slv'length);
begin
for idx in slv_norm'range loop
sl_str_v := to_bstring(slv_norm(idx));
res_v(idx) := sl_str_v(1);
end loop;
return res_v;
end function;
Using the bit-wise format has the advantage that any non-01 values will show
with the exact std_logic
value, which is not the case for e.g. hex
presentation.
Then make process that writes the strings from std_logic
and
std_logic_vector
to file for example at rising_edge(clk)
like:
library std;
use std.textio.all;
...
process (clk) is
variable line_v : line;
file out_file : text open write_mode is "out.txt";
begin
if rising_edge(clk) then
write(line_v, to_bstring(rst) & " " & to_bstring(cnt_1) & " " & to_bstring(cnt_3));
writeline(out_file, line_v);
end if;
end process;
The example above uses rst
as std_logic
, and cnt_1
and cnt_3
as
std_logic_vector(7 downto 0)
. The resulting output in "out.txt" is then:
1 00000000 00000000
1 00000000 00000000
1 00000000 00000000
0 00000000 00000000
0 00000001 00000011
0 00000010 00000110
0 00000011 00001001
0 00000100 00001100
0 00000101 00001111
0 00000110 00010010