Designing, Simulating and Implementing a Simple Car Alarm on a Xilinx FPGA – Part II


Implement a simple car alarm on a Xilinx Spartan 3 Starter kit board from Digilent, using the VHDL code exported from Multisim 12.0 in our first part of this tutorial,

In this second part we will implement and test the logic circuit of the Car Alam on a Xilinx FPGA Spartan 3 Starter kit board.


A complete workflow of an FPGA design is normally:

  • Problem/requirements analysis, vendor selection
  • Behavioral model design
  • RTL (Verilog or VHDL) design
  • RTL verification
  • Logic synthesis
  • Implementation
  • Static timing analysis
  • Bitstream generation

The first two steps have already been taken in part I. In this part the next steps will be taken (except for Static timing analysis, obviously).


– VHDL code from part I
– Digilent Spartan 3 Starter Kit board
Xilinx ISE Design Suite 13.4 or superior

Implentation on FPGA

Launch Xilinx ISE  Design Suite, get into the Project Navigator, and start a New Project pressing the button for New Project. Xilinx ISE Project Navigator controls all aspects of the development flow of our FPGA. We will use it to launch all development tasks.

Give the project a name such as Car_alarm and fill all the fields appropriately, including pointing to the drive and directory in your PC where you will keep the project files:

New project in Xilinx ISE

Press Next > button, and choose the fields again as shown:

Second window of new project

Press again Next > and you will see the final window:

Window shows a summary of our choices

Press Finish and we will get back to the Xilinx ISE Project Navigator.

We will concentrate for now on Implementation and Hierarchy window:

Hierarchy in Project Navigator

We will add Car_alarm.vhd source (from part I of this post) , by pressing with the right button of the mouse on XC3S200-5FT256 and Add Source:

Step to add VHDL source

Car_alarm.vhd will now be part of our project Hierachy window:

Car_Alarm behavioral as part of Hierachy

If ones presses onto the Car_Alarm behavioral in Hierarchy window, the desktop window will show the code.

We will check the syntax in the Processes window just below the Hierachy window on the left side of workspace, by pressing with the right button of the mouse on Check Syntax:

Run syntax verfication

Hopefull the syntax will be right and the Processes window will be now as shown below:

Car_alarm.vhdl syntax is ok

And the Console windows will report success:

Console with report of syntax check

We will now add Constraints file  in order to Synthetize next and implement the VHDL code. The Constraints file (UCF) will tell the Xilinx ISE the pins arrangements  (I/O planning) of our  Spartan 3 board.

The Contraints file can also have timing, offset, false and or multicycle paths, and other relevant constraints. In our case, with simple logic circuit, only I/O pin arrangements are required.

Our Xilinx ISE Project Navigator gives us an interface PlanAhead tool that permits the constraints file to be written. In Processess window press with the right button of the mouse I/O Planning (PlanAhead) and Run:

Run PlanAhead for I/O configuration

The following window will pop up:

Window informing inexistence of Constraints file

Press Yes button and PlanAhead will open. Once the start up has been made with our VHDL file, the following Welcome window will open:

Welcome window

The window show the link of PlanAhead User Guide pdf which is worth reading. Press Close button.

In PlanAhead within I/O Ports window expand the Scalar ports where you will see the 4 ports we defined in part I.

I/O Ports window

We will check  the Digilent Spartan 3 User Manual to configure Contraints of the pins. In page 19 we see the slider switch connections:

Slider switch connections in Spartan 3 board

In page 20 we see the LED connections:

LED connections in Spartan 3 board

DOOR will be SW2 i.e. H14;
KEY will be SW1 i.e. G12;
SEAT will be F12;
and ALARM will be LD0 i.e. K12.

Hence within Site of I/O ports we will introduce these values:

Values introduced in I/P Ports

We will not savw the project in File > Save Project

Save the project

We will next Exit and return to the ISE Project Navigator in order to now Synthetize.

In Processes window  Run Synthetize – XST and the process result will be:

Running Synthetize

Hopefully if everything is right it will be successful as show:

Sucessful Synthetizing

We will now run Implement Design in Processes window and the result will be similar as shown:

Results of Implement Design

Next we will generate programming bit file, which will be used to program our Spartan 3 board. Run

Running Generate Programming File

If all goes well the result on the right side will show success:

Sucessful Generate Programming File

The Console window will show:

Report in Console window

We will now program our Spartan S3 board. It is assumed that you have the Digilentboard duly configured to “see” the USB Jtag programming cable, and Digilent Adept 2 chaintool is installed in your PC.

Within Processes window choose Configure Run Manage. Right click with your mouse and Run as shown

Run Manage Configuration Project

Digilent Adept 2 will open. Click on Boundary Scan:

The empty workspace will show:

Message in ISE Impact’s workspace window

Do as it says: Right clich to initialize chain. Choose the option as shown below:

The result will be:

Succesful device identification

Press Yes button

NOTE: We will not program the PROM. This process requires configuration in Adept 2.0 by launching Create PROM file before doing anything else in ISE Project Navigator.

A window will pop up, and we will introuce the bit file we have generated in our Car_alarm project directory.

Assigning the bit file

A new pop up window will invite us to assign PROM file:

Window to Assign PROM file

We will press bthe button Bypass. A new window will pop up:

Final Assign window

Press OK and the result will be:

Assign result: Identify Sucessful

We will now right click XC3S200 icon in order to program the board:

Program the FPGA

Device will be programming and hopefully will be hopefully successful as shown below

Succesful programming

Testing the project

The alarm circuit will light up a LED (LD0) on Spartan 3 Starter kit board only when the key (SW1) is in the ignition and either the door (SW2) is open or the seatbelt (SW0) is not fastened. The variables are:

                                    Key = 0      key is not in the ignition
                                    Key = 1      key is in the ignition
                                    Door = 0    door is open
                                    Door = 1    door is closed
                                    Seat = 0     seat belt is not fastened
                                    Seat = 1     seat belt is fastened
                                    Alarm = 0   alarm is not ON
                                    Alarm = 1   alarm is ON

Hence the Truth table is:

Where A (SW2) = DOOR, B (SW1) = KEY and C (SW0) = BELT.

On Spartan S3 board, from rightmost switch in direction to left, we have BELT, KEY and DOOR.

DEMO Video:


The VHDL, Constraints and bit file can downloaded from here.


A complete Workflow has been shown in this two parts tutorial of a simple Car Alarm.

From Truth table we have obtained the Boolean expression, and we have simulated in Multisim 12.0 and exported the respective VHDL code.

In this part of tutorial we imported the file in Xilinx ISE Project Navigator, and we did all the procedures to implement the VHDL on an FPGA.

We have sucessfully programmed the Digilent Spartan 3 Starter kit board, and tested our Car Alarm circuit we designed in part I.


About Tayeb

Electronics engineer, part-time webmaster and owner of "Aliatron", a tech-oriented company registered in Portugal and Mozambique. Owner of "EU Halal", a trading and consulting company in Halal & Tayyib, 100% stun-free compliant.
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3 Responses to Designing, Simulating and Implementing a Simple Car Alarm on a Xilinx FPGA – Part II

  1. Pingback: Designing, Simulating and Implementing a Simple Car Alarm on a Xilinx FPGA – Part I | RedAcacia

  2. Pingback: Finite-State Machine Design of a Simple Car Security Alarm on a Xilinx FPGA – Part I | RedAcacia

  3. Pingback: Design and Simulate a Digital Circuit in NI Multisim and Implement on a Digilent Basys 2 Spartan-3E FPGA Board | RedAcacia

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