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LAB3/src/effect_selector.vhd

@@ -1,20 +1,27 @@
 LIBRARY IEEE;
 USE IEEE.STD_LOGIC_1164.ALL;
 
+-- Entity: effect_selector
+-- Purpose: Routes joystick input to different audio control parameters based on effect mode
+--          Acts as a multiplexer/router for joystick control signals
 ENTITY effect_selector IS
     GENERIC (
-        JOYSTICK_LENGHT : INTEGER := 10
+        JOYSTICK_LENGHT : INTEGER := 10  -- Width of joystick position data (10-bit = 0-1023 range)
     );
     PORT (
-        aclk : IN STD_LOGIC;
-        aresetn : IN STD_LOGIC;
+        -- Clock and reset signals
+        aclk : IN STD_LOGIC;      -- Main clock input
+        aresetn : IN STD_LOGIC;   -- Active-low asynchronous reset
 
-        effect : IN STD_LOGIC;
-        jstck_x : IN STD_LOGIC_VECTOR(JOYSTICK_LENGHT - 1 DOWNTO 0);
-        jstck_y : IN STD_LOGIC_VECTOR(JOYSTICK_LENGHT - 1 DOWNTO 0);
-        volume : OUT STD_LOGIC_VECTOR(JOYSTICK_LENGHT - 1 DOWNTO 0);
-        balance : OUT STD_LOGIC_VECTOR(JOYSTICK_LENGHT - 1 DOWNTO 0);
-        lfo_period : OUT STD_LOGIC_VECTOR(JOYSTICK_LENGHT - 1 DOWNTO 0)
+        -- Control and input signals
+        effect : IN STD_LOGIC;    -- Effect mode selector (0=volume/balance mode, 1=LFO/balance mode)
+        jstck_x : IN STD_LOGIC_VECTOR(JOYSTICK_LENGHT - 1 DOWNTO 0);  -- X-axis joystick position
+        jstck_y : IN STD_LOGIC_VECTOR(JOYSTICK_LENGHT - 1 DOWNTO 0);  -- Y-axis joystick position
+
+        -- Output control parameters
+        volume : OUT STD_LOGIC_VECTOR(JOYSTICK_LENGHT - 1 DOWNTO 0);     -- Volume control output
+        balance : OUT STD_LOGIC_VECTOR(JOYSTICK_LENGHT - 1 DOWNTO 0);    -- Balance control output
+        lfo_period : OUT STD_LOGIC_VECTOR(JOYSTICK_LENGHT - 1 DOWNTO 0)  -- LFO period control output
     );
 END effect_selector;
 
@@ -22,27 +29,39 @@ ARCHITECTURE Behavioral OF effect_selector IS
 
 BEGIN
 
+    -- Main control logic process
+    -- Routes joystick axes to appropriate audio control parameters based on selected mode
     PROCESS (aclk)
     BEGIN
 
         IF rising_edge(aclk) THEN
 
             IF aresetn = '0' THEN
-                volume <= (OTHERS => '0');
-                balance <= (OTHERS => '0');
-                lfo_period <= (OTHERS => '0');
+                -- Reset all outputs to zero (minimum values)
+                volume <= (OTHERS => '0');      -- Minimum volume
+                balance <= (OTHERS => '0');     -- Full left balance
+                lfo_period <= (OTHERS => '0');  -- Minimum LFO period
 
             ELSE
+                -- Normal operation: Route joystick inputs based on effect mode
+
+                -- X-axis always controls balance regardless of mode
+                -- This provides consistent left/right audio balance control
                 balance <= jstck_x;
 
+                -- Y-axis control depends on selected effect mode
                 IF effect = '1' THEN
-                    -- LFO control
+                    -- LFO Mode: Y-axis controls Low Frequency Oscillator period
+                    -- Used for tremolo, vibrato, or other modulation effects
                     lfo_period <= jstck_y;
+                    -- Volume remains at last set value (not updated in LFO mode)
 
                 ELSE
-                    -- volume/balance control
+                    -- Volume/Balance Mode: Y-axis controls overall volume level
+                    -- Traditional audio mixer control mode
                     volume <= jstck_y;
-                    
+                    -- LFO period remains at last set value (not updated in volume mode)
+
                 END IF;
 
             END IF;