--============================================================================
-- Project 		: line Control
-- Programmer	: Byungchan Son
-- Function		: line 價薦腳扁
-- Language		: VHDL
--============================================================================
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.numeric_std.all;
--============================================================================
-- 澇免仿 器飄 瀝狼
--============================================================================
entity uart_tranceiver is
	port(
		-- 矯膠袍 腳齲
		reset : in std_logic;
		clock : in std_logic;
		-- com 腳齲
		tx_line : out std_logic;
		rx_line : in std_logic;
		-- line 力絹何
		com_baudrate : in std_logic_vector(15 downto 0);
		com_control : in std_logic_vector(1 downto 0);
		com_tx_data : in std_logic_vector(7 downto 0);
		com_tx_wrreq : in std_logic;
		com_tx_full : out std_logic;
		com_rx_data : out std_logic_vector(7 downto 0);
		com_rx_rdreq : in std_logic;
		com_rx_empty : out std_logic
		);
end uart_tranceiver;
--============================================================================
-- 備煉 瀝狼
--============================================================================
architecture uart_tranceiver_a of uart_tranceiver is
--------------------------------------------------------------------
-- 郴何 葛碘
--------------------------------------------------------------------
-- com 價腳 滾欺
component transmit_buff
	PORT
	(
		clock		: IN STD_LOGIC ;
		data		: IN STD_LOGIC_VECTOR (7 DOWNTO 0);
		rdreq		: IN STD_LOGIC ;
		wrreq		: IN STD_LOGIC ;
		empty		: OUT STD_LOGIC ;
		full		: OUT STD_LOGIC ;
		q		: OUT STD_LOGIC_VECTOR (7 DOWNTO 0)
	);
end component;
-- com 薦腳 滾欺
component receiver_buff
	port(
		clock		: IN STD_LOGIC ;
		data		: IN STD_LOGIC_VECTOR (7 DOWNTO 0);
		rdreq		: IN STD_LOGIC ;
		wrreq		: IN STD_LOGIC ;
		empty		: OUT STD_LOGIC ;
		q		: OUT STD_LOGIC_VECTOR (7 DOWNTO 0)
		);
end component;
--------------------------------------------------------------------
-- 郴何 腳齲
--------------------------------------------------------------------
--惑怕扁拌 腳齲
-- 薦腳 葛碘
type receive_state is(
	rx_ready,
	rx_start,
	rx_data_accept,
	rx_parity_bit,
	rx_stop_bit
	);
signal rx_current_state, rx_next_state : receive_state;
-- 價腳 葛碘
type transmit_state is(
	tx_ready,
	tx_read_delay,
	tx_read_data,
	tx_data_transmit,
	tx_parity_bit,
	tx_stop_bit
	);
signal tx_current_state, tx_next_state : transmit_state;
------------------------------------------------------------------------------
-- 郴何 腳齲
------------------------------------------------------------------------------
-- baud rate 努釩 慣積扁
signal rx_baudrate_clock : std_logic;
signal rx_baudrate_clock1 : std_logic;
signal rx_baudrate_counter : std_logic_vector(15 downto 0);
signal tx_baudrate_clock : std_logic;
signal tx_baudrate_clock1 : std_logic;
signal tx_baudrate_counter : std_logic_vector(15 downto 0);
-- 薦腳何 腳齲
signal rx_baudrate_enable : std_logic;
signal sync_rx_line : std_logic;
signal clk1_rx_line : std_logic;
signal rx_buffer : std_logic_vector(7 downto 0);
signal rx_bit_count : std_logic_vector(2 downto 0);
-- 價腳何 腳齲
signal tx_baudrate_enable : std_logic;
signal tx_buffer : std_logic_vector(7 downto 0);
signal tx_bit_count : std_logic_vector(2 downto 0);
signal tx_parity : std_logic;
-- 薦腳 滾欺
signal rx_buff_data	: STD_LOGIC_VECTOR (7 DOWNTO 0);
signal rx_buff_wrreq : STD_LOGIC;
-- 價腳 滾欺
signal tx_buff_rdreq : STD_LOGIC;
signal tx_buff_empty : STD_LOGIC;
signal tx_buff_q : STD_LOGIC_VECTOR (7 DOWNTO 0);
--============================================================================
-- 橇肺技輯 矯累
--============================================================================
begin
	----------------------------------------------------------------
	-- 郴何 葛碘 搬急
	----------------------------------------------------------------
	-- com 薦腳 滾欺
	m1 : receiver_buff
	port map(
		clock => clock,
		data  => rx_buff_data,
		rdreq => com_rx_rdreq,
		wrreq => rx_buff_wrreq,
		empty => com_rx_empty,
		q     => com_rx_data
		);
	-- com 價腳 滾欺
	m2 : transmit_buff
	port map(
		clock => clock,
		data  => com_tx_data,
		rdreq => tx_buff_rdreq,
		wrreq => com_tx_wrreq,
		empty => tx_buff_empty,
		full  => com_tx_full,
		q     => tx_buff_q
		);
	----------------------------------------------------------------
	-- baud rate 努釩 慣積扁
	----------------------------------------------------------------
	baudrate_generator : process(
		reset,
		clock,
		rx_baudrate_clock,
		rx_baudrate_counter,
		tx_baudrate_clock,
		tx_baudrate_counter,
		com_baudrate
		)
	begin
		if(reset = '1')then
			-- 惑怕 扁拌
			-- 郴何 腳齲
			rx_baudrate_clock <= '0';
			rx_baudrate_counter <= (others => '0');
			tx_baudrate_clock <= '0';
			tx_baudrate_counter <= (others => '0');
		elsif(clock'event and clock = '1')then
			-- 價腳 baudrate 努釩 慣積扁
			if(tx_baudrate_enable = '1')then
				if(tx_baudrate_counter = com_baudrate)then
					tx_baudrate_clock <= not tx_baudrate_clock;
                    tx_baudrate_counter <= (others => '0');
				else
					tx_baudrate_counter <= tx_baudrate_counter + 1;
                end if;
			else
				tx_baudrate_counter <= (others => '0');
				tx_baudrate_clock <= '0';
			end if;
			-- 薦腳 baudrate 努釩 慣積扁
			if(rx_baudrate_enable = '1')then
				if(rx_baudrate_counter = com_baudrate)then
					rx_baudrate_clock <= not rx_baudrate_clock;
                    rx_baudrate_counter <= (others => '0');
				else
					rx_baudrate_counter <= rx_baudrate_counter + 1;
                end if;
			else
				rx_baudrate_counter <= (others => '0');
				rx_baudrate_clock <= '0';
			end if;
		end if;
	end process;
	----------------------------------------------------------------
	-- 薦腳 葛碘
	----------------------------------------------------------------
	receiver : process(
		reset,
		clock,
		rx_line,
		sync_rx_line,
		clk1_rx_line,
		rx_current_state,
		rx_next_state,
		rx_baudrate_clock,
		rx_bit_count
		)
	begin
		if(reset = '1')then
			-- 惑怕 扁拌
			rx_next_state <= rx_ready;
			-- 郴何 腳齲
			rx_buffer <= (others => '0');
			rx_bit_count <= (others => '0');
			rx_baudrate_enable <= '0';
			rx_baudrate_clock1 <= '0';
			rx_buff_data <= (others => '0');
			rx_buff_wrreq <= '0';
		elsif(clock'event and clock = '1')then
			sync_rx_line <= rx_line;
			clk1_rx_line <= sync_rx_line;
			rx_baudrate_clock1 <= rx_baudrate_clock;
			case rx_current_state is
				when rx_ready =>
					rx_buff_wrreq <= '0';
					if(clk1_rx_line = '1' and sync_rx_line = '0')then
						rx_baudrate_enable <= '1';
						rx_next_state <= rx_start;
					else
						rx_baudrate_enable <= '0';
					end if;
				when rx_start =>
					if(rx_baudrate_clock1 = '0' and rx_baudrate_clock = '1')then
						if(sync_rx_line = '0')then
							rx_next_state <= rx_data_accept;
						else
							rx_next_state <= rx_ready;
						end if;
					end if;
				when rx_data_accept =>
					if(rx_baudrate_clock1 = '0' and rx_baudrate_clock = '1')then
						rx_buffer(7) <= sync_rx_line;
						rx_buffer(6) <= rx_buffer(7);
						rx_buffer(5) <= rx_buffer(6);
						rx_buffer(4) <= rx_buffer(5);
						rx_buffer(3) <= rx_buffer(4);
						rx_buffer(2) <= rx_buffer(3);
						rx_buffer(1) <= rx_buffer(2);
						rx_buffer(0) <= rx_buffer(1);
						if(rx_bit_count = "111")then
							rx_bit_count <= (others => '0');
							if(com_control(1) = '0')then
								rx_next_state <= rx_stop_bit;
							else
								rx_next_state <= rx_parity_bit;
							end if;
						else
							rx_bit_count <= rx_bit_count + 1;
						end if;
					end if;
				when rx_parity_bit =>
					if(rx_baudrate_clock1 = '0' and rx_baudrate_clock = '1')then
						rx_next_state <= rx_stop_bit;
					end if;
				when rx_stop_bit =>
					if(rx_baudrate_clock1 = '0' and rx_baudrate_clock = '1')then
						if(sync_rx_line = '1')then
							rx_buff_data <= rx_buffer;
							rx_buff_wrreq <= '1';
						end if;
						rx_next_state <= rx_ready;
					end if;
			end case;
		end if;
		rx_current_state <= rx_next_state;
	end process;
	----------------------------------------------------------------
	-- 價腳 葛碘
	----------------------------------------------------------------
	transmitter : process(
		reset,
		clock,
		tx_current_state,
		tx_next_state,
		tx_baudrate_clock,
		tx_bit_count
		)
	begin
		if(reset = '1')then
			-- 惑怕 扁拌
			tx_next_state <= tx_ready;
			-- 郴何 腳齲
			tx_buffer <= (others => '0');
			tx_bit_count <= (others => '0');
			tx_baudrate_enable <= '0';
			tx_line <= '1';
			tx_baudrate_clock1 <= '0';
		elsif(clock'event and clock = '1')then
			tx_baudrate_clock1 <= tx_baudrate_clock;
			case tx_current_state is
				when tx_ready =>
					if(tx_buff_empty = '0')then
						tx_buff_rdreq <= '1';
						tx_next_state <= tx_read_delay;
					else
						tx_baudrate_enable <= '0';
					end if;
				when tx_read_delay =>
					tx_buff_rdreq <= '0';
					tx_next_state <= tx_read_data;
				when tx_read_data =>
					tx_buffer <= tx_buff_q;
					tx_baudrate_enable <= '1';
					tx_line <= '0';
					tx_parity <= '0';
					tx_next_state <= tx_data_transmit;
				when tx_data_transmit =>
					if(tx_baudrate_clock1 = '1' and tx_baudrate_clock = '0')then
						tx_line <= tx_buffer(0);
						tx_parity <= tx_parity xor tx_buffer(0);
						tx_buffer(0) <= tx_buffer(1);
						tx_buffer(1) <= tx_buffer(2);
						tx_buffer(2) <= tx_buffer(3);
						tx_buffer(3) <= tx_buffer(4);
						tx_buffer(4) <= tx_buffer(5);
						tx_buffer(5) <= tx_buffer(6);
						tx_buffer(6) <= tx_buffer(7);
						if(tx_bit_count = "111")then
							tx_bit_count <= (others => '0');
							if(com_control(1) = '0')then
								tx_next_state <= tx_stop_bit;
							else
								tx_next_state <= tx_parity_bit;
							end if;
						else
							tx_bit_count <= tx_bit_count + 1;
						end if;
					end if;
				when tx_parity_bit =>
					if(tx_baudrate_clock1 = '1' and tx_baudrate_clock = '0')then
						tx_line <= tx_parity xor com_control(0);
						tx_next_state <= tx_stop_bit;
					end if;
				when tx_stop_bit =>
					if(tx_baudrate_clock1 = '1' and tx_baudrate_clock = '0')then
						if(tx_bit_count = "001")then
							tx_bit_count <= (others => '0');
							tx_next_state <= tx_ready;
						else
							tx_bit_count <= tx_bit_count + 1;
							tx_line <= '1';
						end if;
					end if;
			end case;
		end if;
		tx_current_state <= tx_next_state;
	end process;
	----------------------------------------------------------------
	-- 肺流 腳齲
	----------------------------------------------------------------
end uart_tranceiver_a;
--============================================================================
-- 場
--============================================================================