PC/CP120 Digital Electronics Lab

Introduction to Quartus II Software Design using Test Benches for Simulation

(Note: If you have done the previous task which involves "forcing" the inputs for simulation, the first several sections of this document are identical. If you saved your previous work, you can skip to the testbench section where the changes begin.)

In this tutorial, we will show you how you capture the schematic design for the automatic door opener circuit using Altera Quartus II software.

The Problem

We are designing a circuit for an automatic door like those you see at supermarkets. The door should open only when a person is detected walking through or when a person presses a switch (such as the wheelchair button) to have the door open. The door should only operate if it has been unlocked.

• output: f = 1 (Opens Door)
• inputs
  • p = 1 Person Detected
  • h = 1 Switch Holding the Door Open
  • c = 1 Door Closed/Locked
• Want door to open when
  • the door is unlocked and person walking through (c=0 and p=1)
  • the door is unlocked and the switch is set to hold it open (c=0 and h=1)

I: Drive

During Labs you will need to save all your work under a directory called CP120 in your Home Directory (drive I:)

To get to your I: or your Home Directory double click on My Computer icon on the desktop.

Under I:\CP120 create the following folders

• intro
• task
• project

Copy this directory from the I drive to the E drive. There are currently probelms saving files directly to the I drive. Be sure to copy your files back to the I drive after you are done.

Getting Started with Altera Quartus

Launch the Altera Quartus software. You should see a screen such as this:

Creating a New project

Select the File → New Project Wizard; a window like the following will appear.

To select the working directory use the button to browse and select E:\CP120\intro.
Name the project DoorOpener. (Note that the next field gets filled in automatically.) Select Finish.
Don't uses spaces in file or directory names.

Creating a new Schematic design

Select File → New - A window as seen in the following picture will open.

Select 'Block Diagram/Schematic File' and press OK.

This should open a palette where you will design your circuit. This palette is designated Block1.bdf. Save this graphic design file as DoorOpener in your "intro" directory. The file will be given the bdf extension; bdf stands for block design file and contains schematics, symbols or block diagrams.

Adding text

1. Select the A below the arrow to the left of your Block Diagram/Schematic File window (also known as the palette).
2. Select a point near the top left in the window with the left mouse key.
3. Type your name and then hit the Enter key.
4. Type your project name and then hit the Enter key.
5. Type the following equation, f = hc' + pc' , and then hit the Enter key.
6. Hit the Esc (escape) key to end text additions.

Adding a Component

1. Click the library icon.

   

   The Symbol dialog box will appear. This window lists the available Altera libraries as seen in this image.

   

2. Expand the /altera/quartus10.0sp1/quartus/libraries folder, expand the primitives folder and then expand the logic folder.
3. In the logic folder, select the and2 component by double clicking on it (or by selecting it with a single click, then selecting OK).
4. Click the pointer at the desired location in the Block Diagram/Schematic Editor window to insert the AND symbol into the design file.

Repeat these steps to enter an OR (or2) gate and a NOT (not) gate.

(If you wanted to add multiple NOT gates, you could select the Repeat-insert mode box.)

In the same manner that you placed a gate onto the palette, add three input pins and one output pin from the Symbol libraries. Input pins can be found under primitives | pin | inputs. Output pins can be found under primitives | pin | outputs.

Name your input and output pins as you name them in your equation. Double click on the pin name to change its name.

Rearrange your devices in approximately the placement you would like for the logic diagram you are trying to construct. You can move a component by selecting it with your mouse, holding down the left button and moving it to another location on the palette.

Save your design. It is a good idea to save your design often, just in case something bad happens . Save the bdf file with the same name as the project.
Don't use spaces in any file names.

Wiring your circuit

Select the orthogonal node tool. Place your pointer on the output of one of the input pins and hold the left mouse button down. You should see a cross-hairs or + appear at the output.

Drag your pointer to the input of the AND gate. Every time you release the mouse key, the line (wire) ends. If your wire did not reach the AND gate, you can add to the wire by putting your mouse over an end of the wire and again selecting it with your left mouse button and dragging your mouse to another position.
Don't run wires along the edge of a device. This can cause simulation problems.
Don't leave inputs and outputs right next to the chips. Make sure you can actually see some wire between them, otherwise you may have simulation problems.

Note: Make sure you do not make the wire too long. If you drag it too far you will see an x; and this is considered an open connection and your design will not compile.

To delete a wire or a portion of a wire, simply click on it (it should change color to indicate selection) and press the delete key.

If wires are connected to the component as you are moving it, the wires will drag and stay connected to the component. This is referred to as "rubber banding" and is a feature of all major schematic entry design packages. (You can turn rubberbanding on and off using the rubberbanding tool. )Add the rest of the wires needed to connect the logic diagram.

The window should look something like image below. Save your design.

Printing

We will not print today. But you will need to know how for your project.

To print, go to File | Print. If you want to change what appears on the printout or how it appears, go to File | Page Setup change print settings. Before printing, you can view what the print will look like by selecting File | Print Preview

Choosing a Device

The programmable device which we'll use for our design can be chosen now.

Select Assignments | Device from the pull-down menu.

Select MAX7000S from the "Family" pull-down list. Select the "Specific device selected" and then choose EPM7064SLC44-10, which is the device we are using in our lab. Select "OK."

Circuit Compilation

You will need to compile your design to ensure you do not have any errors in your circuit (e.g. you do not have any open connections, etc.)

Click on Processing | Compiler Tool to start compilation. Then click start.

Circuit Simulation

Before simulating, some preparation is required.

Configure NativeLink settings:

• NOTE: This is DONE ONCE PER PROJECT and the information is stored with the project information.
• Select Assignments | Settings. The Settings dialog box appears.
  
  
• In the Category list, select EDA Tool Settings | Simulation . The Simulation page appears.
• In the Tool name list, select ModelSim. [Do not turn on Run gate-level simulation automatically after compilation.]
• Format for output netlist should default to VHDL and the output directory to simulation/modelsim. [Select/enter if necessary.]
  
  
• Select More EDA Netlist Writer Settings and change the following options:
  • Turn ON Generate netlist for functional simulation only.
  • Enter the Location of user compiled simulation library, e.g. C:/MSim_lib [if necessary].
  • Select OK.
  
  
  
• Select More NativeLink Settings and change the following option:
  • Enter the Location of user compiled simulation library, e.g. C:/MSim_lib [if necessary].
  • Select OK

Convert the schematic diagram into VHDL code for simulation.

• ModelSim requires that the system be specified in an HDL (Hardware Definition Language); we will be using VHDL
• Have the schematic open and then select File | Create/Update | Create HDL Design File from Current File.

  

• In the pop-up window, select file type as VHDL and the file name will show the name and path of the file. The VHDL file and the BDF file have the same name but different extensions (for example, if your BDF file is example.bdf, the VHDL file created is example.vhd).

  

Add the VHDL file to the project and compile for simulation.

• Open the VHDL file using File | Open. Then add it to the project using Project | Add Current File to Project.
  

  

  

  + Note: The VHDL file has three parts:
  1. the library definitions including work where your project will be stored,
  2. the entity definition which is a wrapper that defines the inputs and outputs to the design component, and
  3. the architecture which defines what your component does.
• Remove the BDF file from the project (system can't handle two source files for the same circuit) by selecting Project | Add/Remove Files in Project and then selecting the BDF file and Remove. Note that this does not delete the file (and we do not want to delete the file). (You don't even need to close it.)

  

  

• Compile the circuit for a functional simulation by selecting Processing | Start | Start Analysis & Elaboration.
  
  

  

Library Compilation

It may be necessary to compile the libraries for your device family before you simulate.
Click on Tools | Launch EDA Simulation Library Compiler.

The MAX7000S family should already be selected, so click Start Compilation.

Don't worry if you get any error messages.

Create a testbench to automate your simulation.

• You can get Quartus to produce a shell testbench file by selecting Processing | Start | Start Test Bench Template Writer.
  
  

  

  There will now be a file in your simulation\modelsim directory. Open it.
  
  

  

• The section near the bottom of the file is where you put statements for your simulation.
  
  

  

  Insert instructions for how you want the inputs to change through the simulation.
  
  Here's an example of the beginning for a very simple simulation:
  
  

  

• After making the changes, you need to change the settings to include your testbench.
  
  

  

  
  
  Choose a New testbench.
  
  

  

  
  
  Give the test bench a name. It doesn't have to be the same as the file name.
  
  

  

  
  
  Now add the testbench file.
  
  

  

  
  
  Select OK to close the New Test Bench Settings window..
  
  

  

  
  
  Select OK to close the Test Benches window..
  
  

  

  
  
  Select OK to close the Settings window..
  
  

  

• Select the VHT file. Then add it to the project using Project | Add Current File to Project.
  

  

• Prepare for a functional simulation by selecting Processing | Start | Start Analysis & Elaboration.
  
  

  

Launch the ModelSim simulator.

• Select Tools | Run EDA Simulation Tool | EDA RTL Simulation. ModelSim will display splash screen. ModelSim will load libraries and compile the project. The transcript pane at the bottom of the screen indicates the scripts that have been run (or are running).

  

• Now your work library will contain two VHDL files; your circuit and your testbench. Select both, and right click to compile both.

  

• Select Simulate | Start Simulation to put ModelSim in simulator mode. The Start Simulation Window opens.

  

• The Start Simulation window contains many tabs. The Design tab lists the designs available for simulation; most are system libraries. At the top of list will be work (default name for the library containing your program), expand work by selecting the '+'. All components in your design will be listed, select the component that is the testbench.

  

  Select OK. This will bring up other panes.
• Then the left hand side of the screen should now contain a sim tab that displays the design units in your circuit and the supporting libraries. When a design unit is selected in the sim tab, the corresponding signals are shown in the objects window on the right hand side of the screen. Signals that are preceded with a plus (+) sign indicate a bus (a group of wires with common function).

  

Open waveform window and add signals to be simulated.

• For each signal that you want to add to the simulation, right click on the signal name in the Objects window and select Add | To Wave | Selected Signal. Typically, you would want to add all inputs and outputs. A waveform window will appear in the work area.

  

• Alternatively, you can add a range of signals at once by selecting the 1st signal and then, while holding down the shift key, select the last signal in the range. Then right click in the selected signal region and select Add | To Wave | Selected Signals. A waveform window will appear in the work area.

  

• When all signals are selected, expand the Wave window.
• If the Wave window is not floating above the ModelSim main screen, use the top left icon in the wave window to undock the window. Expand the detached window.

  

• In the tool icons, find the window that contains the period of the signal, e.g. 100ns. Immediately to the right of that window will be the run simulation icon (looks like a page with a blue down arrow beside it). Select run simulation. You should see the inputs that you entered and the outputs from your system on the waveform. The period of the run will correspond to the time in the period window. All signals should be green. If any signals are red, then one or more of the inputs was not specified.

  

  

• The output can be zoomed.

  

  

  

• To zoom back out to see the original, you can go to View | Zoom | Zoom Full.

  

• The waveform can be exported to an image file.

  

Demonstrate the circuit to the lab demonstrator before you leave.

Copy your directory from the E drive to the I drive. Delete them from the E drive and empty the Recycle Bin so they don't get used by someone else later.