---------------------------------------------------------------------------------- -- Project: YASG (Yet another signal generator) -- Project Page: https://github.com/id101010/vhdl-yasg/ -- Authors: Aaron Schmocker & Timo Lang -- License: GPL v3 -- Create Date: 18:47:36 05/23/2016 ---------------------------------------------------------------------------------- library IEEE; use IEEE.STD_LOGIC_1164.ALL; use IEEE.NUMERIC_STD.ALL; entity controller is Port ( clk : in STD_LOGIC; -- Clock Input rst: in STD_LOGIC; -- High active, async reset enc_right : in STD_LOGIC; -- Encoder Input: 1= Direction Right, 0 = Direction Left enc_ce : in STD_LOGIC; -- Encoder Input: Clock Enable for Signal above enc_btn: in STD_LOGIC; -- Encoder Input: Debounced Button (High active) form : in unsigned(1 downto 0); -- Form selection (mapping see dds.vhd) lcd_busy: in STD_LOGIC; -- LCD Feedback: Busy Signal: 1= LCD is currently busy lcd_data: out unsigned(7 downto 0); -- LCD Output: Data output lcd_newchar: out STD_LOGIC; -- LCD Output: Send a new character to the lcd lcd_newpos : out STD_LOGIC; -- LCD Output: Send a new position/adress to the lcd freq_out : out unsigned (16 downto 0)); -- Frequency Ouput (Treshould in Hz) end controller; architecture Behavioral of controller is -- FSM with the following states: type states is(S_WAIT, -- wait till the lcd is no longer busy, and returns in a specific state afterwards S_FORM_PREF, -- prints the form prefix ("Form:") S_FREQ_PREF, -- frequenz prefix ("Freq: 00000 Hz") S_FORM_CONT, -- form content ("Rechteck, Sinus...") S_FREQ_CONT, -- frequenz content ("-----") S_IDLE ); -- controller is idle and waits on user input signal state_reg, state_next : states := S_WAIT; -- Current State signal ret_state_reg, ret_state_next: states := S_FORM_PREF; -- State to return to, after S_WAIT ----- Edge detection registers ----- signal btn_old_reg, btn_old_next : std_logic := '0'; signal enc_old_reg, enc_old_next: std_logic :='0'; signal form_old_reg, form_old_next : unsigned (1 downto 0) := (others => '0'); signal digpos_reg, digpos_next : unsigned(2 downto 0) := (others => '0'); -- digitnr which is currently edited 0-4 signal charcnt_reg, charcnt_next : unsigned(3 downto 0) := (others => '0'); -- character number which is currently being written out -- Decimal value (0-9) of the sigle frequency digits (array 5x 4bit) type storage_digit is array (0 to 7) of unsigned (3 downto 0); signal digit_reg, digit_next : storage_digit := (others => (others => '0')); signal lcd_newchar_reg,lcd_newchar_next : std_logic := '0'; -- Register for the LCD Newchar signal signal lcd_newpos_reg,lcd_newpos_next : std_logic := '0'; -- Register for the LCD Newpos signal signal lcd_data_reg, lcd_data_next: unsigned(7 downto 0) :=(others => '0'); -- Register for the LCD Databus signal signal freq_out_reg, freq_out_next : unsigned (16 downto 0) := (others => '0'); -- Register for the frequency ouput (in hz) ----------------Constants--------------------------------- -- Signal Form Prefix: type character_array_short is array (0 to 7) of character; constant str_form_pref : character_array_short := ( 'F', 'o', 'r','m',':', others => ' ' ); -- Signal Frequency Prefix/Postfix: type character_array_long is array (0 to 15) of character; constant str_freq_pref : character_array_long := ( 'F', 'r', 'e','q',':',' ','0','0','0','0','0',' ','H','z', others => ' ' ); -- Signal Form names: type character_form_array is array (0 to 3, 0 to 7) of character; constant str_form : character_form_array := ( ('S','q','u','a','r','e',' ',' '), ('S','a','w','t','o','o','t','h'), ('T','r','i','a','n','g','l','e'), ('S','i','n','e',' ',' ',' ',' ') ); -- Possible improvement: Write a helper function which initializes those character arrays from a string begin -- State register process (sequential) proc1: process(clk,rst) begin if(rst='1') then digpos_reg <= (others => '0'); digit_reg <= (others => (others => '0')); btn_old_reg <= '0'; enc_old_reg <='0'; form_old_reg <= "00"; charcnt_reg <= (others => '0'); lcd_newchar_reg <= '0'; lcd_newpos_reg <= '0'; lcd_data_reg <= (others => '0'); freq_out_reg <=(others => '0'); -- On reset: wait on display startup and then start with S_FORM_PREF state state_reg <= S_WAIT; ret_state_reg <= S_FORM_PREF; elsif(rising_edge(clk)) then digpos_reg <= digpos_next; digit_reg <= digit_next; btn_old_reg <= btn_old_next; enc_old_reg <= enc_old_next; form_old_reg <= form_old_next; charcnt_reg <= charcnt_next; lcd_newchar_reg<= lcd_newchar_next; lcd_newpos_reg<= lcd_newpos_next; lcd_data_reg <= lcd_data_next; freq_out_reg <= freq_out_next; state_reg <= state_next; ret_state_reg <= ret_state_next; end if; end process proc1; freq_out <= freq_out_reg; lcd_data <= lcd_data_reg; lcd_newchar <= lcd_newchar_reg; lcd_newpos <= lcd_newpos_reg; -- Next State logic process (combinational) NSL: process(digit_reg,enc_right,enc_ce,enc_btn,digpos_reg,btn_old_reg, charcnt_reg, lcd_busy, lcd_data_reg, state_reg, ret_state_reg, enc_ce,enc_old_reg, form_old_reg, form) begin -- To avoid latches the most signals are assigned with their previous value (Exceptions marked) digit_next <= digit_reg; digpos_next <= digpos_reg; btn_old_next <= btn_old_reg; enc_old_next <= enc_old_reg; form_old_next <= form_old_reg; charcnt_next <= charcnt_reg; lcd_newchar_next <= '0'; -- next newchar is always 0, becasue normally we dont want to send anything lcd_newpos_next <= '0'; -- same for newpos lcd_data_next <= lcd_data_reg; state_next <= state_reg; ret_state_next <= ret_state_reg; -- The next statement produces two warnings which can be safely ignored: -- xst:643 - The result of a <...>-bit multiplication is partially used... -- Put together the frequency as a 17 bit vector (in hz) out of the single decimal places freq_out_next <= resize( resize(digit_reg(0), 4) + resize(digit_reg(1) ,4)* 10 + resize(digit_reg(2) ,7)* 100 + resize(digit_reg(3) ,10) * 1000 + resize(digit_reg(4) ,14) * 10000 ,17); case state_reg is -- switch on current state when S_WAIT => -- lcd is currently busy if(lcd_busy = '0') then --lcd is no longer busy state_next<= ret_state_reg; -- return to state given by ret_state end if; when S_FORM_PREF => -- print the form prefix state_next <= S_WAIT; -- always wait for lcd_busy=0 after this state if(charcnt_reg < 7 ) then -- not 8 characters written yet: Send characters charcnt_next <= charcnt_reg + 1; -- increase character position ret_state_next <= S_FORM_PREF; -- return into this state after wait -- Output current character (Multiplexer). Implemented as an array lookup with cast from character to ascii value lcd_data_next <= to_unsigned(character'pos(str_form_pref(to_integer(resize(charcnt_reg,3)))),8); lcd_newchar_next <= '1'; -- signal the lcd driver that a new character is ready for writing else -- all 8 characters written: Change adress to line 2 (as preparation for S_FREQ_PREF) charcnt_next <= (others => '0'); -- reset charcnt lcd_data_next <= x"40"; -- Start adress for line 2 lcd_newpos_next <= '1'; -- signal the lcd driver that a new position is available ret_state_next <= S_FREQ_PREF; -- continue with S_FREQ_PREF state end if; when S_FREQ_PREF => -- print the frequency prefix/postfix if(charcnt_reg < 15 ) then -- not all 16 characters written yet charcnt_next <= charcnt_reg + 1; state_next <= S_WAIT; ret_state_next <= S_FREQ_PREF; lcd_data_next <= to_unsigned(character'pos(str_freq_pref(to_integer(charcnt_reg))),8); lcd_newchar_next <= '1'; else -- all charcters written charcnt_next <= (others => '0'); state_next <= S_FORM_CONT; -- print the Form content now end if; when S_FORM_CONT => -- print the form content state_next <= S_WAIT; ret_state_next <= S_FORM_CONT; charcnt_next <= charcnt_reg + 1; if(charcnt_reg < 1 ) then -- Step 1: Set address lcd_data_next <= x"06"; -- adress character 7 on line 1 lcd_newpos_next <= '1'; elsif(charcnt_reg < 9) then -- Step 2 (8x): Print a character of the form lcd_data_next <= to_unsigned(character'pos(str_form(to_integer(form),to_integer(resize(charcnt_reg-1,3)))),8); lcd_newchar_next <= '1'; else -- Step 3: Set adress/cursor back to current digit charcnt_next <= (others => '0'); lcd_data_next <= x"4A" - digpos_reg; -- adress character 11 on line 2 - digit position lcd_newpos_next <= '1'; ret_state_next <= S_IDLE; end if; when S_FREQ_CONT => -- print the frequency content state_next <= S_WAIT; if(charcnt_reg < 1 ) then -- Step 1: Set address for current digit charcnt_next <= charcnt_reg + 1; ret_state_next <= S_FREQ_CONT; lcd_data_next <= x"4A" - digpos_reg; -- adress character 11 on line 2 - digit position lcd_newpos_next <= '1'; elsif(charcnt_reg = 1) then -- Step 2: Print current digit charcnt_next <= charcnt_reg + 1; ret_state_next <= S_FREQ_CONT; lcd_data_next <= to_unsigned(character'pos('0'),8) + digit_reg(to_integer(digpos_reg)); lcd_newchar_next <= '1'; else -- Step 3: Reset adress/cursor back to current digit (auto increment of display cannot be disabled) ret_state_next <= S_IDLE; charcnt_next <= (others => '0'); lcd_data_next <= x"4A" - digpos_reg; -- adress character 11 on line 2 - digit position lcd_newpos_next <= '1'; end if; when S_IDLE => -- Controller is idle and wait on user input -- Update edge dectection helper registers: btn_old_next <= enc_btn; enc_old_next <= enc_ce; form_old_next <= form; if(form /= form_old_reg) then -- form changed state_next <= S_FORM_CONT; -- print form elsif(enc_ce='1' and enc_old_reg ='0') then -- positive egde on encoder clock enable if(enc_right='1') then -- encoder was turned right if(digit_reg(to_integer(digpos_reg)) = to_unsigned(9,4)) then -- digit value = 9 digit_next(to_integer(digpos_reg)) <= to_unsigned(0,4); -- set digit value to 0 else -- digit value < 9 digit_next(to_integer(digpos_reg)) <= digit_reg(to_integer(digpos_reg)) + 1; -- increase digit value end if; else -- encoder was turned left if(digit_reg(to_integer(digpos_reg)) = to_unsigned(0,4)) then -- digit value = 0 digit_next(to_integer(digpos_reg)) <= to_unsigned(9,4); -- set digit value to 9 else -- digit value > 0 digit_next(to_integer(digpos_reg)) <= digit_reg(to_integer(digpos_reg)) -1; -- decrease digit value end if; end if; state_next <= S_FREQ_CONT; -- print frequency elsif(enc_btn ='1' and btn_old_reg='0') then -- positive edge on push button if(digpos_reg = to_unsigned(4,3)) then -- digit_pos = 4 digpos_next <= to_unsigned(0,3); -- set digit pos = 0 else -- digit pos < 4 digpos_next <= digpos_reg + 1; -- increase digit pos end if; state_next <= S_FREQ_CONT; -- print frequency (also updates the cursor position) end if; when others => null; -- do nothing, if we are in a different state end case; end process NSL; end Behavioral;