--- Quote Start ---
I have made this program as part of an assignment where I'm supposed to design a one bit voter, for micro controllers use in a student satellite. The code works except the part where i am trying to reset the circuit.
In the sync process i have a signal, clear_input_ok, if this is set to '1' by the reset, the input_ok is supposed to be set to "1111" in the combinatorial process. This doesn't work though, I've asked my TA, and my professor, and they haven't fount a solution, and say that it should work. I will include source code. Thanks in advance!
library IEEE;
use IEEE.STD_LOGIC_1164.all;
entity Voter is
port(
CLK : in STD_LOGIC;
a : in STD_LOGIC;
b : in STD_LOGIC;
c : in STD_LOGIC;
d : in STD_LOGIC;
reset : in STD_LOGIC;
y : out STD_LOGIC;
status : out STD_LOGIC_VECTOR(2 downto 0)
);
end Voter;
--}} End of automatically maintained section
architecture Voter of Voter is
SIGNAL input_ok: STD_LOGIC_VECTOR(3 downto 0);
SIGNAL clear_input_ok: STD_LOGIC;
SIGNAL async_status: STD_LOGIC_VECTOR(2 downto 0);
SIGNAL result_y: STD_LOGIC;
begin
sync:
process (CLK,reset)
begin
if reset = '1' then
clear_input_ok <= '1';
else clear_input_ok <= '0';
end if;
if clk = '1' then
status <= "000";
y <= result_y;
status <= async_status;
end if;
end process sync;
comb:
process (a,b,c,d, clear_input_ok)
VARIABLE vote_one : INTEGER RANGE 0 TO 4;
VARIABLE vote_null : INTEGER RANGE 0 TO 4;
VARIABLE failed : INTEGER RANGE 0 TO 4;
VARIABLE result : STD_LOGIC;
begin
failed := 0;
vote_one := 0;
vote_null := 0;
async_status <= "000";
if (clear_input_ok = '1') THEN
report("if statement runs!");
input_ok <= "1111";
end if;
------- inkrements voting variables----------
if (input_ok(0) = '1') THEN
if (a='1') THEN
vote_one:= vote_one +1;
else vote_null:= vote_null +1;
end if;
else
vote_one := vote_one +1;
vote_null := vote_null +1;
end if;
if (input_ok(1) = '1') THEN
if (b='1') THEN
vote_one:= vote_one +1;
else vote_null:= vote_null +1;
end if;
else
vote_one := vote_one +1;
vote_null := vote_null +1;
end if;
if (input_ok(2) = '1') THEN
if (c='1') THEN
vote_one:= vote_one +1;
else vote_null:= vote_null +1;
end if;
else
vote_one := vote_one +1;
vote_null := vote_null +1;
end if;
if (input_ok(3) = '1') THEN
if (d='1') THEN
vote_one:= vote_one +1;
else vote_null:= vote_null +1;
end if;
else
vote_one := vote_one +1;
vote_null := vote_null +1;
end if;
----- figure out result ------
if (vote_one = 4) THEN
result := '1';
end if;
if (vote_null = 4) THEN
result := '0';
end if;
-----check if there is contradicting values, and how many? and uppdate failed----------
if (a /= result) OR input_ok(0) = '0' THEN
input_ok(0) <= '0';
failed := failed +1;
end if;
if (b /= result) OR input_ok(1) = '0' THEN
input_ok(1) <= '0';
failed := failed +1;
end if;
if (c /= result) OR input_ok(2) = '0' THEN
input_ok(2) <= '0';
failed := failed +1;
end if;
if (d /= result) OR input_ok(3) = '0' THEN
input_ok(3) <= '0';
failed := failed +1;
end if;
----- uppdate status------
if failed = 0 THEN
async_status <= "000";
end if;
if failed = 1 THEN
async_status <= "001";
end if;
if failed = 2 THEN
async_status <= "010";
end if;
if failed > 2 THEN
async_status <= "111";
end if;
------uppdate result-------
result_y <= result;
end process comb;
end Voter;
--- Quote End ---
you must be updating input_ok back to zeros on last statements in the comb process. Remember it is sequential process and last statements overwrite.
Honored Contributor
