Acessing state registers of a FSM for diagnostic purposes

[anindya]

ENTITY MOORE IS
PORT(A,CLK,RST:IN BIT;
F:OUT BIT);
END MOORE;

ARCHITECTURE FSMOF MOORE IS

SUBTYPE STATE_TYPE IS STD_
LOGIC_VECTOR (2DOWNTO 0);
SIGNAL STATE:STATE_TYPE;
CONSTANT S0:
STATE_TYPE:="001";
CONSTANT S1:
STATE_TYPE:="010";
CONSTANT S2:
STATE_TYPE:="100";
SIGNAL CURRENT_STATE,
NEXT_STATE :STATE_TYPE;
BEGIN
FFROCESS (CLK,RST)BEGIN
IF (RST=’1’)THEN
CURRENT_STATE <=S0 ;
ELSIF (CLK’EVENT AND CLK=’1’)
THEN
CURRENT_STATE<=NEXT_STATE;
END IF ;
END PROCESS FF ;
LOGICROCESS (A,
CURRENT_STATE)BEGIN
CASE CURRENT_STATE IS
WHEN S0=>F <= ’0’;
IF (A=’0’)THEN
NEXT_STATE <=S 0;
ELSE
NEXT_STATE <=S1;
END IF;
WHEN S1=>F <= ’0’;
IF (A=’0’)THEN
NEXT_STATE <=S2;
ELSE
NEXT_STATE <=S1;
END IF;
WHEN S2=>F <= ’1’;
IF (A=’0’)THEN
NEXT_STATE <=S0;
ELSE
NEXT_STATE <=S1;
END IF;
WHEN OTHERS =>
CURRENT_STATE <=S0;
END CASE;
END PROCESS;
END FSM ;

the Question is at run time how can i access the state register having So/S1 for diagnostic purposes ?

 

[tariq786]

put your code like that

ENTITY MOORE IS
PORT(A,CLK,RST:IN BIT;
F:OUT BIT);
END MOORE;

ARCHITECTURE FSMOF MOORE IS

SUBTYPE STATE_TYPE IS STD_
LOGIC_VECTOR (2DOWNTO 0);
SIGNAL STATE:STATE_TYPE;
CONSTANT S0:
STATE_TYPE:="001";
CONSTANT S1:
STATE_TYPE:="010";
CONSTANT S2:
STATE_TYPE:="100";
SIGNAL CURRENT_STATE,
NEXT_STATE :STATE_TYPE;
BEGIN
FF:PROCESS (CLK,RST)BEGIN
IF (RST=’1’)THEN 
CURRENT_STATE <=S0 ;
ELSIF (CLK’EVENT AND CLK=’1’)
THEN
CURRENT_STATE<=NEXT_STATE;
END IF ;
END PROCESS FF ;
LOGIC:PROCESS (A,
CURRENT_STATE)BEGIN
CASE CURRENT_STATE IS
WHEN S0=>F <= ’0’;
IF (A=’0’)THEN
NEXT_STATE <=S 0;
ELSE
NEXT_STATE <=S1;
END IF;
WHEN S1=>F <= ’0’;
IF (A=’0’)THEN
NEXT_STATE <=S2;
ELSE
NEXT_STATE <=S1;
END IF;
WHEN S2=>F <= ’1’;
IF (A=’0’)THEN
NEXT_STATE <=S0;
ELSE
NEXT_STATE <=S1;
END IF;
WHEN OTHERS =>
CURRENT_STATE <=S0;
END CASE;
END PROCESS;
END FSM ;

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Now to your question. Declare current_state as output. This is how you can debug states of moore fsm.