-- 庫聲明
library IEEE;
use IEEE.STD_LOGIC_1164.all;
use WORK.SEND_PACKAGE.all;

entity send_core is
	generic (
	
	DATA_BIT : integer := 64;-- 數(shù)據(jù)位個數(shù)
	TOTAL_BIT : integer := 66;-- 總數(shù)據(jù)個數(shù)(1b起始位，64b數(shù)據(jù)，1b校驗位，1b停止位）
	PARITY_RULE:PARITY := ODD 
	);
	port (
	-- 時鐘信號
	clk : in std_logic;
    rdclk:out std_logic;            -- 讀fifo的時鐘
    rdempty:in std_logic;           --讀空標志
    rdreq:out std_logic;
	-- 復(fù)位、使能子模塊的信號
	reset_parts : out std_logic;
	reset_dt:out std_logic;
	ce_parts : out std_logic;
	new_data:in std_logic;
	-- 和移位寄存器的接口信號
	send_si : out std_logic;
	-- 計數(shù)器時鐘選擇信號和計數(shù)器計數(shù)到達上閾的指示信號
	overflow : in std_logic;
	RxD:in std_logic;
	-- 輸出選擇信號
	sel_out : out std_logic;
	parity:in std_logic;
--	dout:out std_logic_vector(5 downto 0);
	-- 提供給CPU的接口信號
	send_bus : in std_logic_vector(DATA_BIT-1 downto 0)
--	send_bus_2: out std_logic_vector(63 downto 0);
--	send_over : out std_logic
    );
end send_core;


architecture send_core of send_core is

-- 內(nèi)部信號
signal state : UART_STATE := UART_IDLE;
signal send_buf : std_logic_vector(67 downto 0);
signal si_count : integer range 0 to 100 := 0;
signal reg6:std_logic_vector(5 downto 0):= (others => '0');
signal rv_count: integer range 0 to 10 :=0;
--signal send_bus_2:std_logic_vector(63 downto 0);

begin
	-- 主過程
	main: process(clk)
	begin
	
	rdclk <= clk;
	
          if rising_edge(clk) then
			 case state is        
				when UART_IDLE =>      -- 空閑狀態(tài)
					reset_parts <= '0';-- 復(fù)位子模塊
					reset_dt <= '0';
					ce_parts <= '0';   -- 子模塊使能無效
		--		if new_data = '0' then
			         if (rdempty ='0')then 			
				          rdreq <= '1' ;    
				    	  sel_out <= '0';    -- 使得輸出保持為'1'
					      si_count <= TOTAL_BIT-1;-- 初始化串行加載序列的索引變量
					      state <= UART_LOAD;-- 改變狀態(tài)為加載
			         else 
			              state <= UART_IDLE; 
                     end if;
           --     else
          --           state <= RECV_DETECT;
         --       end if;                   
				-------- 數(shù)據(jù)加載和發(fā)送狀態(tài)--------
					
				when UART_LOAD =>      -- 加載狀態(tài)
			--	send_bus_2 <=send_bus;
		        rdreq <= '0';
				if overflow = '1' then -- 如果overflow信號為'1'，表示數(shù)據(jù)加載完成
	     	  		sel_out <= '0';  -- 使得輸出保持為'1'
					reset_parts <= '0';-- 復(fù)位子模塊
					ce_parts <= '0'; -- 子模塊使能信號無效
					state <= UART_SEND;-- 改變狀態(tài)為發(fā)送
				else
					if not(si_count = TOTAL_BIT-1) then -- 通過增加si_count，
						si_count <= si_count+1;         --生成串行加載序列
					else
						si_count <= 0;
					end if;
					reset_parts <= '1'; -- 子模塊復(fù)位信號無效
					ce_parts <= '1';    -- 子模塊使能信號有效
				end if;

				when UART_SEND =>       -- 發(fā)送狀態(tài)
	    	    	sel_out <= '1';            -- 選擇輸出為TxD
				if overflow = '1' then	   -- 如果overflow為'1'，表示發(fā)送完成
	--				send_over <= '1';      -- 輸出發(fā)送完成的指示信號
			    	sel_out <= '0';
			        reset_dt <= '1';
					state <= RECV_DETECT;-- 改變狀態(tài)為發(fā)送完成
				else
					reset_parts <= '1';    -- 子模塊復(fù)位信號無效
					ce_parts <= '1';       -- 子模塊使能信號有效
				end if;				
				
				when RECV_DETECT =>
	                reset_dt <= '1';
	--	    		send_over <= '0';          -- 恢復(fù)發(fā)送完成指示信號
					reset_parts <= '1';    -- 子模塊復(fù)位信號無效
					ce_parts <= '1';       -- 子模塊使能信號有效
		 		if new_data = '1' then	
        			rv_count <= 0;   
	                reset_dt <= '0';       
					state <= RECV;			
		--            state <= UART_END_SEND;
		        else 
                    state <= RECV_DETECT;
                 end if;
		        			
				    
				when RECV =>
					reset_parts <= '1';    -- 子模塊復(fù)位信號無效
					ce_parts <= '1';       -- 子模塊使能信號有效
				if not(rv_count =  4) then 
    	    	    reg6(5 downto 1) <= reg6(4 downto 0) ; 
	                reg6(0) <= RxD; 
				    rv_count <= rv_count +1;
				else 
				    state <= CHECK;    
				end if;
				
				when CHECK =>
					reset_parts <= '1';    -- 子模塊復(fù)位信號無效
					ce_parts <= '1';       -- 子模塊使能信號有效
		    		case reg6 is
		            when "000000" =>           --接收正確
		            reg6 <= "000000";
	--	            dout <= reg6;
		    		state <= UART_END_SEND;
		
		            when "000001"  =>          --接收錯誤,重發(fā)
	--	            dout <= reg6;
		            reg6 <= "000000";
					reset_parts <= '0';-- 復(fù)位子模塊
					reset_dt <= '0';
					ce_parts <= '0';   -- 子模塊使能無效
	   	    	    sel_out <= '0';    -- 使得輸出保持為'1'
					si_count <= TOTAL_BIT-1;-- 初始化串行加載序列的索引變量
		            state <= UART_LOAD;
		
		            when "000010" =>           --接收FIFO滿，等待
	--	            dout <= reg6;
		            reg6 <= "000000";
					reset_dt <= '1';
		            state <= RECV_DETECT;
		
		            when others =>
	--	            dout <= reg6;
		            reg6 <= "000000";
		            state <= UART_END_SEND;
		            end case;
				 
				when UART_END_SEND =>      -- 發(fā)送完成狀態(tài)
				ce_parts <= '0';           -- 子模塊使能信號無效
	--			send_over <= '0';          -- 恢復(fù)發(fā)送完成指示信號
				state <= UART_IDLE;		   -- 改變狀態(tài)為空閑		
			end case;
		end if;
	end process;	
	
	-- 生成串行加載序列 (奇偶校驗）
	send_buffer: process(send_bus,parity)
	begin							
		send_buf(0) <= '0';    -- 存儲起始位
		send_buf(64 downto 1) <= send_bus(63 downto 0);-- 存儲數(shù)據(jù)位
		if PARITY_RULE = ODD or PARITY_RULE = EVEN then 
		   send_buf(65) <= parity;
		   send_buf(67 DOWNTO 66) <=  (others => '1');
		else
		   send_buf(67 DOWNTO 65) <= (others => '1');
		end if;
	end process;
	
	-- 串行輸入選擇
	si_switch: process(si_count)
	begin
	   if (si_count < TOTAL_BIT ) then
		  send_si <= send_buf(si_count);-- 將send_buf里面的數(shù)據(jù)送到send_si端口上
	   else
	      send_si <= '1';
	   end if;
	end process;				

end send_core;