Music Synthesizer with Chord Player, Harmonics, Dynamics, and PMOD Integration

Team Members:

• Vincent Thai
• William Pan
• Yale Wang

Overview:

For this project, we designed and implemented a digital music synthesizer capable of playing chords, harmonic tones, and dynamic audio effects. We also integrated a PMOD numpad for real-time note control. The system was implemented using Verilog and simulated on an FPGA.

Features:

1. Chord Player & Harmonics Implementation:

• Chord Player: Capable of playing up to 4 notes simultaneously, selected from a defined range (1A to 6B).
• Harmonics: Plays the first, second, and third harmonic overtones alongside the fundamental frequency.
• Song ROM: Supports multiple songs, including one based on "Si Veo A Tu Mama" by Bad Bunny.
• Key Modules:
  • note_player: Adapted to play frequency instead of note for precise harmonics.
  • harmonics_player: Outputs sine waves for the fundamental and overtones.

2. Dynamics Implementation:

• Full ADSR (Attack, Decay, Sustain, Release) envelope to control the amplitude of notes.
• Generalized enough to support various envelope phases for different instrument sounds.
• Button 3 on the FPGA toggles dynamics on or off.

3. PMOD-Numpad Implementation:

• Allows real-time note input from a PMOD numpad.
• Each key (1-8) plays a corresponding note (4C-5C).
• The numpad input is visualized on the FPGA’s LEDs.

4. Division Approximation (Extra Feature):

• Division approximation using a custom ROM and right bit-shifting to efficiently handle scaling factors without native division operations in Verilog.

Block Diagrams:

Testing:

• Comprehensive testbenches were created for key modules (notes_player, divide, key_board) to ensure correct functionality.
• Waveform visualizations were used to verify sound wave correctness and timing.

Challenges:

• Initial timing issues with song and note loading were resolved after detailed waveform analysis.
• Division and scaling approximations were implemented to handle non-power-of-two operations.
• Key debouncing on the PMOD numpad required significant debugging but was resolved by addressing a timing violation elsewhere in the code.

Future Work:

• Support for more complex songs and dynamic effects.
• Integration of different envelope shapes for a wider range of instrument emulation.
• Improved user interface for real-time control of note dynamics and harmonics.

How to Run:

1. Hardware Requirements:
   • FPGA development board with support for PMODs.
   • PMOD numpad.
2. Software:
   • Xilinx Vivado for Verilog simulation and bitstream generation.
3. Setup:
   • Load the provided Verilog code into Vivado.
   • Simulate using the provided testbenches.
   • Deploy to your FPGA board and connect the PMOD numpad.
4. Controls:
   • Use the numpad to play notes in real-time.
   • Toggle dynamics on/off with Button 3.