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- update comments

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- add led_level_controller Const
This commit is contained in:
Davide Cavagnola
2025-06-03 14:55:23 +02:00
parent 79373768fa
commit dff2eb439d
11 changed files with 73 additions and 72 deletions
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18
LAB3/src/LFO.vhd
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@@ -3,7 +3,7 @@ USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.NUMERIC_STD.ALL;
-- Entity: LFO (Low Frequency Oscillator) - Alternative Implementation
-- Purpose: Applies tremolo effect to audio by modulating amplitude with a triangular wave
-- Purpose: Applies effect to audio by modulating amplitude with a triangular wave
-- This is a simplified, single-process implementation compared to the pipelined version
-- Provides real-time audio amplitude modulation for musical effects
ENTITY LFO IS
@@ -24,13 +24,13 @@ ENTITY LFO IS
-- Slave AXI Stream interface (audio input)
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=left, 1=right)
s_axis_tready : OUT STD_LOGIC; -- Ready to accept input data
-- Master AXI Stream interface (audio output)
m_axis_tvalid : OUT STD_LOGIC; -- Output data valid signal
m_axis_tdata : OUT STD_LOGIC_VECTOR(CHANNEL_LENGHT - 1 DOWNTO 0); -- Modulated audio sample output
m_axis_tdata : OUT STD_LOGIC_VECTOR(CHANNEL_LENGHT - 1 DOWNTO 0); -- Modulated audio sample output
m_axis_tlast : OUT STD_LOGIC; -- Channel indicator passthrough
m_axis_tready : IN STD_LOGIC -- Downstream ready signal
);
@@ -57,7 +57,7 @@ ARCHITECTURE Behavioral OF LFO IS
-- Triangular wave generation signals
-- Note: Using signed counter with extra bit to handle full range calculations
SIGNAL tri_counter : SIGNED(TRIANGULAR_COUNTER_LENGHT DOWNTO 0) := (OTHERS => '0'); -- Triangular wave amplitude
SIGNAL tri_counter : SIGNED(TRIANGULAR_COUNTER_LENGHT DOWNTO 0) := (OTHERS => '0'); -- Triangular wave amplitude
SIGNAL direction_up : STD_LOGIC := '1'; -- Wave direction: '1' = ascending, '0' = descending
-- AXI4-Stream control signals
@@ -106,7 +106,7 @@ BEGIN
step_counter <= 0; -- Reset counter for next period
-- Check for triangular wave direction changes at extremes
-- Note: Using (2^n - 2) and 1 instead of (2^n - 1) and 0 to avoid edge cases
-- Note: Using (2^n - 2) and 1 instead of (2^n - 1) and 0 due to process signal assignment
IF tri_counter = (2 ** TRIANGULAR_COUNTER_LENGHT) - 2 THEN
direction_up <= '0'; -- Switch to descending at near-maximum
@@ -180,8 +180,8 @@ BEGIN
-- Data input logic: Process new audio samples when available and output is ready
IF s_axis_tvalid = '1' AND (m_axis_tready = '1' OR m_axis_tvalid_int = '0') THEN
IF lfo_enable = '1' THEN
-- Apply LFO tremolo effect: multiply audio sample by triangular wave
-- This creates amplitude modulation (tremolo effect)
-- Apply LFO effect: multiply audio sample by triangular wave
-- This creates amplitude modulation (effect)
m_axis_tdata_temp <= signed(s_axis_tdata) * tri_counter;
s_axis_tlast_reg <= s_axis_tlast; -- Register channel indicator
@@ -212,11 +212,11 @@ BEGIN
-- LFO Implementation Summary:
-- 1. Generates triangular wave at frequency controlled by joystick input
-- 2. When enabled: multiplies audio samples by triangular wave (tremolo effect)
-- 2. When enabled: multiplies audio samples by triangular wave (multiplier value range from 0 to 1)
-- 3. When disabled: passes audio through unchanged (bypass mode)
-- 4. Uses proper AXI4-Stream handshaking for real-time audio processing
--
-- Tremolo Effect Characteristics:
-- Effect Characteristics:
-- - Frequency range: Approximately 0.1Hz to 10Hz (typical for audio LFO)
-- - Modulation depth: Controlled by TRIANGULAR_COUNTER_LENGHT generic
-- - Waveform: Triangular (linear amplitude changes, smooth transitions)