[SOLVED] synchronous 4 bit counter problem

[Digit0001]

Hi

Can someone help me on how would you code the following:
A synchronous 4 bit counter up performs the counting and the loading on the falling edge of the clock. The clear is an asynchronous input which resets the counter. The counter generates a carry Cout in state 15 if T = '1'. The counter increments if P and T = 1.

This is what i have done. Can someone tell me if this is correct?

entity ques4 is
port(P,T : in std_logic;
	 Clear,Load : in std_logic;
	 Clk : in std_logic;
	 cout : in std_logic;
	 D : in std_logic_vector(3 downto 0);
	 Q : out std_logic_vector(3 downto 0));
end ques4;

architecture Behavioral of ques4 is
signal count : std_logic_vector(3 downto 0);
begin
	process(clk,clear)
	begin
		if(clear = '0') then
			count <= "0000";
		elsif(clk'event and clk='0') then
			if(load = '1') then
				count <= D;
			elsif(T = '1') then
				count <= D;
			elsif(T='1' and P='1') then
				count <= count + "0001";
			end if;
		end if;
	end process;
	Q <= count;
end Behavioral;

P.S

 

[TrickyDicky]

why not simulate it/run it and find out?

You have one problem, it is never going to actually count. the branch (T= '1' and P = '1') can never be reached because it is overridden by the T='1' branch above.

 

[Digit0001]

i have tried it again, can someone tell me where is my mistake, because when i simulate it doesn't give me an output for Q.

architecture Behavioral of ques4 is
signal count : std_logic_vector(3 downto 0);
signal tCout : std_logic;
begin
	process(clk,clear,count,P,T,Load)
	begin	
		if(clear = '1') then
			count <= "0000";
			tCout <= '0';
		elsif(clk'event and clk='0') then
			if(Load = '1') then
				count <= D;
				tCout <= '0';
			elsif(T = '1' and P = '0') then
				tCout <= '1';
			elsif(T = '1' and P = '1') then
				count <= count + '1';
				tCout <= '0';
			else
				count <= count;
			end if;
		end if;
	end process;
		Q <= count;
	Cout <= tCout;
end Behavioral;

 

[TrickyDicky]

nothing wrong with the code, what does your testbech code look like? and what does no output mean?

 

[Digit0001]

solved my problem, something with my coding.