a bit of help with enable

[jazzman519]

the following is code that produces dot and dash tones. i have it hooked up to a buzzer circuit. it works fine. my problem is trying to get it to stop after 3 pulses for a s in morse code. would an adder be the best solution, using an enable and the appropriate dot or dash signal, and then clocking the enable to stop after 3 pulses? any help would be greatly appreciated










library IEEE, unisim;
use IEEE.std_logic_1164.all;
use IEEE.NUMERIC_STD.all;
use unisim.vcomponents.all;
use work.ps2_kbd_pckg.all;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;


entity test_kbd is
generic(
FREQ : natural := 200_000 -- frequency of main clock (KHz)
);
port(
dot : out std_logic;
dash : out std_logic;
clk : in std_logic; -- main clock
ps2_clk : in std_logic; -- keyboard clock
ps2_data : in std_logic; -- keyboard data
s : out std_logic_vector(6 downto 0); -- LED display
tone : out std_logic
);
end entity;


architecture arch of test_kbd is

constant YES : std_logic := '1';
constant NO : std_logic := '0';

signal scancode : std_logic_vector(7 downto 0); -- scancode from keyboard
signal rdy : std_logic; -- indicates when scancode is available
signal s_x : std_logic_vector(6 downto 0); -- next state of LED segments
signal kbd_error : std_logic; -- error receiving scancode from keyboard
signal cnt : std_logic_vector (24 downto 0);
-- signal cnt2 : std_logic_vector (24 downto 0);
-- signal cnt3 : std_logic_vector (24 downto 0);
-- LED segment activation patterns for various numbers and letters-
constant DIG_1 : std_logic_vector(6 downto 0) := "0010010";
constant DIG_2 : std_logic_vector(6 downto 0) := "1011101";
constant DIG_3 : std_logic_vector(6 downto 0) := "1011011";
constant DIG_4 : std_logic_vector(6 downto 0) := "0111010";
constant DIG_5 : std_logic_vector(6 downto 0) := "1101011";
constant DIG_6 : std_logic_vector(6 downto 0) := "1101111";
constant DIG_7 : std_logic_vector(6 downto 0) := "1010010";
constant DIG_8 : std_logic_vector(6 downto 0) := "1111111";
constant DIG_9 : std_logic_vector(6 downto 0) := "1111011";
constant DIG_0 : std_logic_vector(6 downto 0) := "1110111";
constant LETTER_E : std_logic_vector(6 downto 0) := "1101101";
constant LETTER_S : std_logic_vector(6 downto 0) := "1101011";
constant LETTER_O : std_logic_vector(6 downto 0) := "1110111";


begin

u0 : ps2_kbd --
generic map(
FREQ => FREQ
)
port map(
clk => clk, -- clock for the keyboard interface
rst => kbd_error, -- reset the keyboard intfc whenever there is an error receiving a scancode
ps2_clk => ps2_clk, -- clock from the keyboard
ps2_data => ps2_data, -- serial data from the keyboard (valid on falling edge of ps2_clk)
scancode => scancode, -- the scancode received from the keyboard
rdy => rdy, -- indicates when a scancode from the keyboard is available
error => kbd_error -- indicates an error in receiving a scancode from the keyboard
);

-- this maps the scancode received from the keyboard into a pattern on the 7-segment display




s_x <= DIG_1 when scancode = "00010110" else
DIG_2 when scancode = "00011110" else
DIG_3 when scancode = "00100110" else
DIG_4 when scancode = "00100101" else
DIG_5 when scancode = "00101110" else
DIG_6 when scancode = "00110110" else
DIG_7 when scancode = "00111101" else
DIG_8 when scancode = "00111110" else
DIG_9 when scancode = "01000110" else
DIG_0 when scancode = "01000101" else
LETTER_S when scancode = "00011011" else
LETTER_O when scancode = "01000100" else


DIG_1 when scancode = "01101001" else
DIG_2 when scancode = "01110010" else
DIG_3 when scancode = "01111010" else
DIG_4 when scancode = "01101011" else
DIG_5 when scancode = "01110011" else
DIG_6 when scancode = "01110100" else
DIG_7 when scancode = "01101100" else
DIG_8 when scancode = "01110101" else
DIG_9 when scancode = "01111101" else
DIG_0 when scancode = "01110000" else
LETTER_E;

-- update the LED display
process(clk)
begin
if rising_edge(clk) then
if rdy = YES then
s <= s_x; -- update the display each time a scancode is received-
end if;
end if;
end process;

process(clk)
begin

if clk'event and clk='1' then
cnt <= cnt + 1;
end if;
if s_x <= LETTER_O and clk'event and clk='1' then
-- dot <= cnt(22) ; --pin 12
dash <= cnt(24) ; --pin 4
-- tone <= cnt(16) ; --pin 25

end if ;
end process;


process(clk)
begin
if s_x <= LETTER_S and clk'event and clk='1' then
tone <= cnt(22);

end if;
end process;

-- tone <= cnt(22) ; --pin 25



end architecture;