EECS 316: FPGA LAB Deadline 11 April 2005

Objective

In this Lab you will model a finite state machine (FSM) in VHDL, encode the FSM states and implement it as a sequential circuit using Synopsys. You will then simulate the circuit to verify its behavior. Finally, you will download the circuit code onto the FPGA board, and validate the hardware circuit using the I/O switches and display LEDs.

Problem Statement

The example FSM controls a FIFO Queue but to be practical, consider that we want to design a simple digital controller which monitors cars entering and leaving a parking lot. The operation specs are as follows.

• The controller maintains the current COUNT of the total number of cars parked in the lot.
• The lot has a limited number of parking spots, for simplicity twenty (20).
• There are two input sensors at the entrance and exit of the lot. The sensors provide input signals to the controller as cars pass by and the controller increments/decrements the current COUNT. What if two cars enter and exit simultaneously?
• If COUNT=20, then the controller issues a FULL output signal, otherwise the OPEN output signal is on.
• There is a manual input for the lot attendant to override the COUNT for special vehicles.
• A START/STOP input is also available to the attendant, with the STOP input causing a CLOSED output signal.

Design Process

• Describe your specs using a flow chart.
• Model your specs and flow chart as an FSM, clearly defining its states, state transitions inputs and outputs.
• Build a behavioral VHDL model of the FSM. Use your own state assignment and encoding to describe the entire FSM and I/O in VHDL.
• Design your FSM using Synopsys, mapping the FSM into a gate level sequential circuit.
• Simulate your circuit to verify its behavior.
• Prepare your circuit code to download onto the Xilinx FPGA board. Review your design carefully to determine the FPGA inputs and outputs for emulating the circuit. Use some LEDs for outputs. Are there any modifications or code revisions necessary?
• Download your circuit code and then validate its behavior using the I/O switches, LEDs and possibly the HP analyzer.
• Prepare a report of your experience, including description of the methodology, charts, code and documentation, simulation results, and validation results.
• You should demonstarte your working experiment to the Lab assistant.