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Improved documentation of all vhd modules except testbenches and lcd driver

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This commit is contained in:
T-moe
2016-06-19 15:58:29 +02:00
parent 78ea176aac
commit f5f862c044
4 changed files with 163 additions and 142 deletions
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173
controller.vhd
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@@ -25,44 +25,47 @@ entity controller is
end controller;
architecture Behavioral of controller is
type states is(S_WAIT,
-- 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 );
S_IDLE ); -- controller is idle and waits on user input
signal state_reg, state_next : states := S_WAIT;
signal ret_state_reg, ret_state_next: states := S_FORM_PREF;
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 busy_old_reg, busy_old_next : std_logic := '0';
signal form_old_reg, form_old_next : unsigned (1 downto 0) := (others => '0');
--digitnr which is currently edited 0-4
signal digpos_reg, digpos_next : unsigned(2 downto 0) := (others => '0');
signal charcnt_reg, charcnt_next : unsigned(3 downto 0) := (others => '0');
-- array 5x 4bit(0-9)
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';
signal lcd_newpos_reg,lcd_newpos_next : std_logic := '0';
signal lcd_data_reg, lcd_data_next: unsigned(7 downto 0) :=(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');
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',' ',' '),
@@ -71,9 +74,11 @@ architecture Behavioral of controller is
('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
@@ -82,7 +87,6 @@ begin
btn_old_reg <= '0';
enc_old_reg <='0';
busy_old_reg <= '0';
form_old_reg <= "00";
charcnt_reg <= (others => '0');
@@ -92,6 +96,7 @@ begin
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;
@@ -101,7 +106,6 @@ begin
btn_old_reg <= btn_old_next;
enc_old_reg <= enc_old_next;
busy_old_reg <= busy_old_next;
form_old_reg <= form_old_next;
charcnt_reg <= charcnt_next;
@@ -117,143 +121,142 @@ begin
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;
NSL: process(digit_reg,enc_right,enc_ce,enc_btn,digpos_reg,btn_old_reg, charcnt_reg, lcd_busy, lcd_data_reg, busy_old_reg, state_reg, ret_state_reg, enc_ce,enc_old_reg, form_old_reg, form)
-- 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;
busy_old_next <= lcd_busy;
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';
lcd_newpos_next <= '0';
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...
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);
-- 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
when S_WAIT => -- switch on current state
if(lcd_busy = '0' and busy_old_reg ='1' ) then
state_next<= ret_state_reg;
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 =>
state_next <= S_WAIT;
if(charcnt_reg < 7 ) then
charcnt_next <= charcnt_reg + 1;
ret_state_next <= S_FORM_PREF;
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';
else
charcnt_next <= (others => '0');
lcd_data_next <= x"40"; --Start adress for line 2
lcd_newpos_next <= '1';
ret_state_next <= S_FREQ_PREF;
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 =>
if(charcnt_reg < 15 ) then
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
else -- all charcters written
charcnt_next <= (others => '0');
state_next <= S_FORM_CONT;
state_next <= S_FORM_CONT; -- print the Form content now
end if;
when S_FORM_CONT =>
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
lcd_data_next <= x"06"; --adress character 7 on line 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
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
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 =>
when S_FREQ_CONT => -- print the frequency content
state_next <= S_WAIT;
if(charcnt_reg < 1 ) then
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
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
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 =>
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
state_next <= S_FORM_CONT;
elsif(enc_ce='1' and enc_old_reg ='0') then
if(enc_right='1') then
if(digit_reg(to_integer(digpos_reg)) = to_unsigned(9,4)) then
digit_next(to_integer(digpos_reg)) <= to_unsigned(0,4);
else
digit_next(to_integer(digpos_reg)) <= digit_reg(to_integer(digpos_reg)) + 1;
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
if(digit_reg(to_integer(digpos_reg)) = to_unsigned(0,4)) then
digit_next(to_integer(digpos_reg)) <= to_unsigned(9,4);
else
digit_next(to_integer(digpos_reg)) <= digit_reg(to_integer(digpos_reg)) -1;
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;
elsif(enc_btn ='1' and btn_old_reg='0') then
if(digpos_reg = to_unsigned(4,3)) then
digpos_next <= to_unsigned(0,3);
else
digpos_next <= digpos_reg + 1;
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;
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;