LAB3/src/led_level_controller.vhd

@@ -8,24 +8,24 @@ USE IEEE.MATH_REAL.ALL;
 --          Processes stereo audio samples and drives a bar graph LED display
 ENTITY led_level_controller IS
     GENERIC (
-        NUM_LEDS : POSITIVE := 16;          -- Number of LEDs in the level meter display
+        NUM_LEDS : POSITIVE := 16; -- Number of LEDs in the level meter display
-        CHANNEL_LENGHT : POSITIVE := 24;    -- Width of audio data (24-bit audio samples)
+        CHANNEL_LENGHT : POSITIVE := 24; -- Width of audio data (24-bit audio samples)
-        refresh_time_ms : POSITIVE := 1;    -- LED refresh rate in milliseconds (1ms = 1kHz update rate)
+        refresh_time_ms : POSITIVE := 1; -- LED refresh rate in milliseconds (1ms = 1kHz update rate)
-        clock_period_ns : POSITIVE := 10    -- System clock period in nanoseconds (10ns = 100MHz)
+        clock_period_ns : POSITIVE := 10 -- System clock period in nanoseconds (10ns = 100MHz)
     );
     PORT (
         -- Clock and reset signals
-        aclk : IN STD_LOGIC;        -- Main clock input
+        aclk : IN STD_LOGIC; -- Main clock input
-        aresetn : IN STD_LOGIC;     -- Active-low asynchronous reset
+        aresetn : IN STD_LOGIC; -- Active-low asynchronous reset
 
         -- LED output array (bar graph display)
-        led : OUT STD_LOGIC_VECTOR(NUM_LEDS - 1 DOWNTO 0);      -- LED control signals (1=on, 0=off)
+        led : OUT STD_LOGIC_VECTOR(NUM_LEDS - 1 DOWNTO 0); -- LED control signals (1=on, 0=off)
 
         -- AXI4-Stream Slave Interface (Audio Input)
-        s_axis_tvalid : IN STD_LOGIC;                                       -- Input data valid signal
+        s_axis_tvalid : IN STD_LOGIC; -- Input data valid signal
-        s_axis_tdata : IN STD_LOGIC_VECTOR(CHANNEL_LENGHT - 1 DOWNTO 0);    -- Audio sample input
+        s_axis_tdata : IN STD_LOGIC_VECTOR(CHANNEL_LENGHT - 1 DOWNTO 0); -- Audio sample input
-        s_axis_tlast : IN STD_LOGIC;                                        -- Channel indicator (0=right, 1=left)
+        s_axis_tlast : IN STD_LOGIC; -- Channel indicator (0=right, 1=left)
-        s_axis_tready : OUT STD_LOGIC                                       -- Always ready to accept data
+        s_axis_tready : OUT STD_LOGIC -- Always ready to accept data
     );
 END led_level_controller;
 
@@ -43,7 +43,8 @@ ARCHITECTURE Behavioral OF led_level_controller IS
 
     -- Audio amplitude storage for both stereo channels
     -- Stores absolute values (magnitude) of left and right audio channels
-    SIGNAL abs_l, abs_r : UNSIGNED(CHANNEL_LENGHT - 1 DOWNTO 0) := (OTHERS => '0'); -- Absolute amplitude registers
+    SIGNAL abs_l : UNSIGNED(CHANNEL_LENGHT - 1 DOWNTO 0) := (OTHERS => '0'); -- Absolute left channel amplitude registers
+    SIGNAL combined_amp : UNSIGNED(CHANNEL_LENGHT - 1 DOWNTO 0) := (OTHERS => '0'); -- Combined amplitude for LED level calculation
 
 BEGIN
 
@@ -52,9 +53,6 @@ BEGIN
 
     -- Capture absolute value of input sample for left/right channel
     PROCESS (aclk)
-
-        VARIABLE signed_sample : SIGNED(CHANNEL_LENGHT - 1 DOWNTO 0);
-
     BEGIN
 
         IF rising_edge(aclk) THEN
@@ -62,20 +60,24 @@ BEGIN
             IF aresetn = '0' THEN
                 -- Reset: Clear both channel amplitude registers
                 abs_l <= (OTHERS => '0');
-                abs_r <= (OTHERS => '0');
+                combined_amp <= (OTHERS => '0');
 
             ELSIF s_axis_tvalid = '1' THEN
                 -- Valid audio data received: Process the sample
-                signed_sample := SIGNED(s_axis_tdata); -- Convert input to signed for ABS operation
 
                 -- Channel routing based on AXI4-Stream tlast signal
-                -- tlast = '1' indicates left channel, tlast = '0' indicates right channel
+                -- tlast = '1' indicates right channel, tlast = '0' indicates left channel
                 IF s_axis_tlast = '1' THEN
-                    -- Left channel: Store absolute value of audio sample
+                    -- Right channel: Combine left and right channel amplitudes
-                    abs_l <= UNSIGNED(ABS(signed_sample));
+                    -- RESIZE ensures the sum fits within the variable's bit width.
+                    -- There isn't data loss since both abs_l and abs(s_axis_tdata) are one bit shorter than combined_amp,
+                    -- due to the absolute value operation.
+                    combined_amp <= RESIZE(abs_l + UNSIGNED(ABS(SIGNED(s_axis_tdata))), combined_amp'LENGTH);
+
                 ELSE
-                    -- Right channel: Store absolute value of audio sample
+                    -- Left channel: Store absolute value of audio sample
-                    abs_r <= UNSIGNED(ABS(signed_sample));
+                    abs_l <= UNSIGNED(ABS(SIGNED(s_axis_tdata)));
+
                 END IF;
 
             END IF;
@@ -117,7 +119,6 @@ BEGIN
     -- Updates only when refresh_tick is active to maintain stable visual display
     PROCESS (aclk)
 
-        VARIABLE combined_amp : UNSIGNED(CHANNEL_LENGHT - 1 DOWNTO 0);
         VARIABLE led_level : INTEGER RANGE 0 TO 2 ** NUMLEDS_BITS := 0;
 
     BEGIN
@@ -131,29 +132,28 @@ BEGIN
             ELSIF refresh_tick = '1' THEN
                 -- LED update cycle: Calculate new LED pattern based on audio amplitude
 
-                -- Combine left and right channel amplitudes
-                -- RESIZE ensures the sum fits within the variable's bit width.
-                -- There isn't data loss since both abs_l and abs_r are one bit shorter than combined_amp,
-                -- due to the absolute value operation.
-                combined_amp := RESIZE(abs_l + abs_r, combined_amp'LENGTH);
-
                 -- Linear scale to LED level conversion to get the best visual effect
                 IF combined_amp = 0 THEN
                     led_level := 0; -- No audio signal, turn off all LEDs
+
                 ELSE
                     led_level := 1 + to_integer(shift_right(combined_amp, CHANNEL_LENGHT - NUMLEDS_BITS));
+
                 END IF;
 
                 -- Saturation protection: Limit LED level to maximum available LEDs
                 -- Prevents overflow and ensures the LED index stays within bounds.
                 IF led_level > NUM_LEDS THEN
                     led_level := NUM_LEDS;
+
                 END IF;
 
                 -- Update LED output based on calculated level
                 led <= (OTHERS => '0');
+
                 IF led_level > 0 THEN
                     led(led_level - 1 DOWNTO 0) <= (OTHERS => '1');
+
                 END IF;
 
             END IF;