Dear All, I have used the Behavioral Compiler to synthesize a FIR filter. I want to constrain a loop. But when I use " find " command to find the loop, it always reports error and get no results.
the command I used is "bc_shell> find cell -hierarchy *filter_loop*" and the feedback is : "Error: Can't find object '*filter_loop*'.(UID-109) {}"
How could I solve this problem?
Thanks a lot. Best Regards
Yiyin Wang My code is below:
LIBRARY ieee;
USE ieee.std_logic_1164.ALL;
USE ieee.std_logic_arith.ALL;
USE ieee.std_logic_signed.ALL;
ENTITY fir_filter2 IS
PORT (
clk : IN std_logic;
rst : IN std_logic;
load : IN std_logic;
data_in : IN signed( 11 DOWNTO 0 );
coeff_addr : IN unsigned( 3 DOWNTO 0 );
start : IN std_logic;
data_out : OUT signed( 11 DOWNTO 0 )
);
END fir_filter2;
ARCHITECTURE behavioral OF fir_filter2 IS
BEGIN
main_proc: PROCESS
SUBTYPE coeff_element IS signed( 11 DOWNTO 0 );
TYPE coeff_type IS ARRAY ( integer RANGE ) OF coeff_element;
VARIABLE coeff : coeff_type( 0 TO 14 );
SUBTYPE history_element IS signed( 11 DOWNTO 0 );
TYPE history_type IS ARRAY ( integer RANGE ) OF history_element;
VARIABLE history : history_type( 0 TO 14 );
VARIABLE sum : signed( 23 DOWNTO 0 );
ATTRIBUTE unroll_new_instance : boolean;
ATTRIBUTE unroll_new_instance OF sum : VARIABLE IS true;
BEGIN
reset_loop: LOOP
-- -- reset the data output --
data_out '0' );
WAIT UNTIL clk'EVENT AND ( clk = '1' );
EXIT reset_loop WHEN ( rst = '1' );
--
-- Initialize all coefficients to zero
--
FOR i IN 0 TO 14 LOOP
coeff( i ) := ( OTHERS => '0' );
END LOOP;
--
-- Initialize history memory to zero
--
FOR i IN 0 TO 14 LOOP
history( i ) := ( OTHERS => '0' );
END LOOP;
main_loop: LOOP
config_loop: LOOP
--
-- Wait until next clock cycle to check for
-- load or filter signals.
--
WAIT UNTIL clk'EVENT AND ( clk = '1' );
EXIT reset_loop WHEN ( rst = '1' );
IF ( start = '1' ) THEN
EXIT config_loop;
END IF;
IF ( load = '1' ) THEN
coeff( conv_integer( '0' & coeff_addr ) ) := data_in;
END IF;
END LOOP config_loop;
--
-- Main filter loop
--
filter_loop: LOOP -- pragma n_unroll 3
-- pragma pipeline_init_interval 1
WAIT UNTIL clk'EVENT AND ( clk = '1' );
EXIT reset_loop WHEN ( rst = '1' );
history( 0 ) := signed( data_in );
sum := ( ( ( history( 0 ) * coeff( 0 ) +
history( 1 ) * coeff( 1 ) ) +
( history( 2 ) * coeff( 2 ) +
history( 3 ) * coeff( 3 ) ) ) +
( ( history( 4 ) * coeff( 4 ) +
history( 5 ) * coeff( 5 ) ) +
( history( 6 ) * coeff( 6 ) +
history( 7 ) * coeff( 7 ) ) ) ) +
( ( ( history( 8 ) * coeff( 8 ) +
history( 9 ) * coeff( 9 ) ) +
( history( 10 ) * coeff( 10 ) +
history( 11 ) * coeff( 11 ) ) ) +
( ( history( 12 ) * coeff( 12 ) +
history( 13 ) * coeff( 13 ) ) +
history( 14 ) * coeff( 14 ) ) );
data_out