vending-machine-fpga-based-vlsi

🥤 Vending Machine with Price Calculator (Verilog)

📌 Project Overview

This project is a digital vending machine designed and simulated using Verilog. It accepts:

• The quantity of items selected
• The price per item and calculates the total cost in real time when the user presses the select button.

The design is fully synchronous with a clock signal and supports reset functionality.

---

⚙️ Features

• Quantity & Price Input: Adjustable via 4-bit and 8-bit inputs.
• Instant Cost Calculation: Multiplies quantity × price_per_item.
• Dispense Signal: Displays the number of items dispensed.
• Total Cost Output: Shows the total price for the current purchase.
• Reset Function: Clears all values.

---

🛠 Implementation Details

Module: vending_machine_with_price.v Testbench: tb_vending_machine_with_price.v

Working Principle

1. Idle State: All outputs are 0 until select is pressed.

2. Transaction: On select, the machine:

   • Dispenses the requested quantity
   • Calculates cost and total

3. Reset / Deselect: Values clear on reset or when select is released.

---

📊 Simulation Output

The design was simulated using GTKWave, and the waveform below shows:

• quantity & price_per_item changing over time
• Correct cost calculation in hexadecimal
• Dispense signal matching the selected quantity

Example:

Time (ns)	Quantity	Price (hex)	Cost (hex)	Cost (dec)
37	2	0A	14	20
65	3	0A	1E	30
105	2	0F	1E	30

---

---

📂 File Structure

📦 vending-machine
 ┣ 📜 vending_machine_with_price.v   # Main Verilog module
 ┣ 📜 tb_vending_machine_with_price.v # Testbench
 ┗ 📷 waveform.png                    # Simulation result

---

🚀 How to Run

1. Open in ModelSim, Vivado, or Icarus Verilog.
2. Compile both .v files.
3. Run the simulation and open the waveform in GTKWave.

---

💡 Future Improvements

• Store last transaction even when select is released.
• Add multiple product selections.
• Implement payment verification before dispensing.

---