added invert signal and can insert errors for parity check

MSF/MSF_decoder/tb/basic_msf_signal_tb.vhd

@@ -20,7 +20,7 @@ architecture basic_msf_signal of basic_msf_signal_tb is
 	signal fast_clk		: std_logic := '0';
 	signal rst			: std_logic := '0';
 	signal read_next	: std_logic := '0';
-	signal h_filter_in	: std_logic := '1';
+	signal h_filter_in	: std_logic := '0';
 
 	signal year_out		: std_logic_vector (7 downto 0) := (others => '0');
 	signal month_out	: std_logic_vector (4 downto 0) := (others => '0');
@@ -34,9 +34,18 @@ architecture basic_msf_signal of basic_msf_signal_tb is
 	
 	signal bit_count	: integer := 58;
 	
+	signal inv_wave		: std_logic := '0'; --invert output msf signal
+	
+	--Type of parity error--
+	type error_type is (year_parity, month_day_parity, 
+	dow_parity, hour_minute_parity, no_parity);
+	
+    signal current_error : error_type := no_parity; --select error
+	
 	--File variables--
 	file f_TIME_DATA	: text;
 	
+	--Parity Check Function--
 	function parity_check(vector : std_logic_vector) return std_logic is
 	    variable count : integer := 0;
 		begin
@@ -55,6 +64,8 @@ architecture basic_msf_signal of basic_msf_signal_tb is
 	
 	
 	
+	
+	
 	begin
 	
 		--Clock Generation--
@@ -162,12 +173,26 @@ architecture basic_msf_signal of basic_msf_signal_tb is
 				
 				msf_a_string(7 downto 0) <= "01111110";
 				
+				--Error insertion--
+				wait until rising_edge(fast_clk);
+				if current_error = year_parity then
+					msf_a_string(37) <= msf_a_string(37) xor '1';
+				elsif current_error = month_day_parity then
+					msf_a_string(28) <= msf_a_string(28) xor '1';
+				elsif current_error = dow_parity then
+					msf_a_string(22) <= msf_a_string(22) xor '1';
+				elsif current_error = hour_minute_parity then
+					msf_a_string(13) <= msf_a_string(13) xor '1';
+				else
+				end if;
+				
 				
 		end process DATA_READ;
 		
 		--Send data as MSF signal--
 		SEND_DATA: process
 			begin
+				h_filter_in <= inv_wave;
 				file_open(f_TIME_DATA, "H:\MSF_Project\time_data.csv", read_mode);
 				while not endfile(f_TIME_DATA) loop
 					--Start of minute indicator--
@@ -175,21 +200,21 @@ architecture basic_msf_signal of basic_msf_signal_tb is
 					read_next <= '1';
 					wait until rising_edge(clk);
 					read_next <= '0';
-					h_filter_in <= '0';
+					h_filter_in <= inv_wave xor '1';
 					wait for 450 ms;
 					wait until rising_edge(clk);
-					h_filter_in <= '1';
+					h_filter_in <= inv_wave;
 					wait for 450 ms;
 					for i in 0 to 58 loop
 						bit_count <= bit_count - 1;
 						wait until rising_edge(clk);
-						h_filter_in <= '0';
+						h_filter_in <= inv_wave xor '1';
 						wait until rising_edge(clk);
-						h_filter_in <= msf_a_string(bit_count) xor '1';
+						h_filter_in <= msf_a_string(bit_count) xor inv_wave;
 						wait until rising_edge(clk);
-						h_filter_in <= msf_b_string(bit_count) xor '1'; --rely on don't care
+						h_filter_in <= msf_b_string(bit_count) xor inv_wave; --rely on don't care
 						wait until rising_edge(clk);
-						h_filter_in <= '1';
+						h_filter_in <= inv_wave;
 						wait for 750 ms;
 					end loop;
 				end loop;