EECS 373 : Libero SoC v11.2 Tool Flow Reference Guide

1/14/2014

Actel Libero is an Integrated Development Environment (IDE) used to configure the SmartFusion chip on your kit. This is a beginning guide to create a project flow within Libero to develop custom hardware for the FPGA and configure Micro-controller SubSystem (MSS). The guide consists of the following sections.

Tool Flow Tutorial for Lab 1

The Libero SoC Project Manager organizes the SmartFusion hardware development tool chain with an intuitive GUI. Libero SoC is installed on the 373 workstations. Libero SoC is also available free from Actel Microsemi at this link with all the functionality required for the course. SoC is currently NOT available on CAEN loads.

Part 1: Project Creation

Open the Libero Project Manger.



Be sure to use Libero SoC V11.2 NOT Libero IDE v9.1. Both are installed on the 373 workstations. You may have to browse for Libero S0C under the program list.

When you first evoke Libero SoC an update window will open consuming the entire screen. Decline the update and close the window.

Libero should then open with the following start page.


Under Projects, select new and the following window will appear.


This window will allow us to name the project, set the projects location and select the device type. The other fields will be populated automatically.  Fill in the fields with the following values.

Name:  andor

Location: You may locate your project in several places. You can put in your user space for this workstation, but you will only have access to it on that computer or you can put it in your UoM directory space (engin-labs.m.storage..etc). The directory should be automatically mapped to the logon unique name. You should see a drive letter associated with it. If it is not, you can map it by opening Computer and clicking on the heading Map Network Drive. Add the path \\engin-labs.m.storage.umich.edu\uniqname.

Note this tutorial was developed using Dropbox but it is not recommended for the lab workstations.
There is no need to create a project folder. Libero will automatically create a project folder at the specified location with the project name.  In this case, a folder named andor will automatically be created.

Caution: Do not use spaces in the directory folder names.

Preferred HDL type: Verilog

Family: SmartFusion

Die: A2F200M3F

Package: 484FBGA

Edit Tool Profile
For this step we need to specify the directory path to a software tool that we will actually use later, but will report errors if we don't specify the path.Click on edit tool profile. The following window should open.



We will add a path to the SoftConsole 3.3 executable. Click the green + button upper right corner.  Add the name SoftConsole33. Add the tool integration SoftConsole. Add the following path in location or browse to C:\Actel\Libero_v9.1\SoftConsole\Eclipse\eclipse.exe



The remaining fields should fill in automatically. Be sure "show latest version" is checked in the lower right corner and Use Design Tool is checked in the mid lower left. The completed fields should look like the following with the exception of the project location. If you use the same login, you should not have to edit the too path for SoftConsole.




Select OK and the following page window will appear.



This project window allows you to enter custom hardware designs, configure standard system devices, synthesize custom hardware and standard hardware, generate hardware programming files and program the device.

The upper left pane displays the project directory and associated files. At this point we only have a project directory.

The mid left pane shows the status of the design flow. It includes all the basic steps in the design flow process. If we collapse all the tools we can see them all as follows.




Design Entry: FPGA hardware can be designed using typical HDLs such as Verilog.
Constrain Design: FPGA pin assignments files are imported with this tool. Note we will actually provide the FPGA pin constraints using an editor  under the Implement Design heading with a convenient editor.
Implement Design: Synthesize design descriptions and generate programming files for the specific FPGA device.
Program Design: Programs or configures the FPGA.
Debug Design: Can be used to insert specialize debugging hardware. We will not use this tool.
Handoff Design for Production: Optimizes design for production removing debug tools and files.
Develop Firmware: This tool will evoke the software development tool (SoftConsole) and automatically import device libraries.

In a typical design build, these tools will run in the background flowing from one tool to the next. You can see the scripts running in the Log or console window in the bottom pane. Any of the Design Flow tools can be run manually by right clicking on the tools and selecting run interactively. Report files are also generated for each one of these tools and are accessible under each heading. These can be useful to debug your design.

Finally the top right pain shows the current design as a graphic. The graphic  represents basic system IO devices such as Ethernet ports, custom hardware modules and interfaces to the ARM processor. When a new project is created, the project manager creates a design that includes  a number of IO pins connected to a large block. This block is referred to as the MSS or Microprocessor SubSystem.  Double clicking on the MSS will open a graphic representation of all the system subcomponents.  It will look like this.


 
Components can be added or removed via their associated check box. Also, some components can be specifically configured by double clicking them. We won't be using this in this tutorial, so close this window and return to the andor project view.  Highlight the MSS, the connected pins and delete them.

Close this window and return to the andor project view.

Part 2: Adding a Custom Hardware Component to the System

Design Entry

For this tutorial we will add a custom hardware component to our design.  It will have the function illustrated in the following schematic.



We will express the design in Verilog. To enter a Verilog file, select Create HDL under Create Design in the tool flow pane.



The following window will appear. Make sure Verilog is selected, un-check initialize standard Verilog format  and name the file myandor. The window should look like this. Press OK. Note we cannot name the file andor since the project name is andor. If you do, an error will be generated when you save the file.




The file andor.v will be opened. Put the following Verilog code in the file. Note, there are two errors in this file for the sake of demonstrating the file checking tools.


module myandor (

input[1:0] SW,
output wire [1:0] LED
             );        

assign LED = SW[0] & SW[1]; //And
assign LED = SW[0] | SW[1] //Or

endmodule

Save the file.  

The code we provided has a simple syntax error. To check syntax, right click in the Verilog file window and select  check HDL.  The console window will indicate an error and identify the line number. Fix the bug, save the file and check the syntax.  There is one more bug that is not a syntax error. We will use the synthesizer to find this bug below.

Next we must instantiate Verilog module in the design. In the Design Hierarchy pane, select myandor.v and drag it into the andor design window. The Verilog file myandor will have the following graphic representation in the window.



We have just one more bit of of design entry  to complete before synthesizing this Verilog. The ports of myandor must be promoted to the the top level so they can be connected to FPGA pins. For each port, right click and select promote to top level.  Your design should look like this when complete.



The project andor should be set as the root design file (top level). To do so, select andor in the Design Hierarchy view, right click and set as root.

If it is already set to the root, it will appear in bold and there will be no choice to set it as the root or top level.



Finally, save project by clicking on the save file icon. Note, you will notice a * next to any file tab that is not saved.


Synthesis
Next we will synthesize the the design. Before we can do that we have to "Generate" the design entry. To generate, double click the icon.


In the Log window you should see a message indicating andor is successfully generated.

Under Implement Design in the Design Flow pane, double click on Synthesis. There is still one error left in our design so it will fail.


You will see an activity symbol to the left of the Synthesize line. You may be prompted to grant access through the firewall. You can acknowledge or cancel. If synthesis was successful, a check mark will appear to the left of the Synthesize line. You will notice that under Synthesize--> Constraints in the Design Flow pane that there is a warning indicated next to the sdc file. This is because we did not include a pin constraint file. We will add the pin constraints later. 

If an error occurred during synthesis, a red symbol will occur next to the synthesize line. It will look something like this.


You can examine the reports file tab in the upper left pane for hints or open the synthesizer in interactive mode. This can be very helpful. Synthesis errors and subtle problems associated with warning are very typical problems in the lab. 

Lets take a look at this case. To open the synthesizer in manual mode, select Synthesize, right click and select Open Interactively. This will open the Synplify Pro application. It will look something like this.  You may have to expand the files listed under Verilog in the directory window.


Notice that errors and warning are associated with myandor.v. Select this file and open by double clicking. The following window will open.

The red highlighted Verilog indicates the error. If you select this error, the error description is indicated in the bottom left window. In this case it is "Multiple non-tristate drivers for net LED[0] in myandor". This is a bit cryptic, but if  you look closely at the LED assignments you will notice that member or LED number is not specified. The first LED assignment should be assigned to LED[0] and the 2nd assignment should be assigned to LED[1].  In some cases you will receive warning highlighted in yellow. Be sure to check these too and make sure they are warnings of no consequence. The blue highlight  on mayandor is just an activity indicator and is not associated with errors.

You can fix this error in the Synplify editor window, save it and synthesize by hitting RUN on the Synplify project page. In this way you can check your correction. The Libero Project manager will ask if you want to update project files such as myandor. Agree to the update. The prompt will look like this for instance.



Close Synplify. You should notice that the Synthesize line in the Design Flow pane has a green check next to it.

Assigning FPGA Pins

Next we must assign the switches, LEDs and test points to devices on the kit. The FPGA pins associated with these devices are listed below for your convenience. A complete list of all the devices and their associated FPGA pins are in a document linked with PIN OUT quick reference below.

To make the assignments, we need to double click on "Create/Edit IO Attributes" under Implement Design--> Compile-->Constrain Place and Route in the Design Flow of the Libero Project Manager as shown below.




This will initiate the Compile process and open the Designer application in a new window.  Designer has many parts, with the IO Attribute Editor opening for pin entry. You will see your port name listed for the andor function. Under the Pin Number column set the pins according to the FPGA pin specification listed at the end of this document. Simply click on the Pin Number window and select the pin number. It should look like the following window when you are complete.



Close this window. You will be asked to commit the design.  Confirm by clicking yes.



Now close the Designer Window. You will asked if you want to save the changes. Confirm by clicking yes.



Programming the FPGA

Finally you must program the FPGA. Be sure that both USB cables of your kit are connected to your workstation.  To start the programming process select Program Device under Program Design in the Design Flow pane in the Libero Project Manager.


The Libero Project Manager will complete all the dependencies required to program the device such as Place and Route and generation of the programming files. You will see the activity indicators as the design flow advances.  This process can take several minutes to complete. Some warning may be generated for the post layout  and timing verification in the Place and Route. You can ignore these.

Once the Programing of the FPGA starts the following notice will be displayed. This part will take awhile (1-2 minutes). On the board, there will be a flashing yellow LED while the device is programming. When it completes, a green LED will turn on next to it. 


When this dialog  disappears,  the process is complete. You should see green check marks next to all the Design Flow from Design Entry to Program Device.

Verify the operation of the logic by observing the LEDs as you activate the switches. The kit with the identified devices is provide here for your convenience.

User LEDs 0 and 1 (top right) should activate when pressing user switch 1 and 2  (lower left and right). Header J22 (upper left) provides the connection to the test points. These can be observed with a scope or logic analyzer.

Keep in mind the switches and LEDs are active low. That is, the switch creates zero when pushed and the led illuminates when a logical 0 is applied.



Summary
  1. Start a project
  2. Enter a design in an HDL file
  3. Instantiate the the design in the top level (project)
  4. Set the project as the ROOT or top level
  5. Generate the top level
  6. Create/Edit IO Attributes
  7. Program Device 
Synthesis, Place and Route and Programming the FPGA can take 1-2 minutes each. If it take more than 3-4 minutes, something is probably wrong and you will probably have to use the task manager to halt the process.

The Libero SoC windows can take a bit of time to update. You may have to wait for the Design Flow window to update status of the tools or an instance in the top level design may take a moment to update.

Part 3: Modifying a Custom Hardware Component

Lets consider a few cases of modifying the design and see how to use the Design Flow to do this.

Case 1

Lets consider changing the original Verilog file so that LED 1 is equal to the exclusive OR of the switches 1 and 2 instead of the or of the switches. Select the Verilog file tab myandor and modify the assignment line to be an exclusive OR as follows.
module myandor (

input[1:0] SW,
output wire [1:0] LED
             );        

assign LED[0] = SW[0] & SW[1]; //And
assign LED[1] = SW[0] ^ SW[1]; //XOr

endmodule
Save the file and the Project Manager should update the status in the Design Flow window. It should look something like this.



To update the design to the FPGA all that is needed is to generate and Double Click on Program Device under Program Design in the Design Flow.  You will notice the Design Flow process will proceed through each step. Green check marks should appear for each step.

You can check to see if LED 1 now exhibits and XOR function.

Summary

In this case you need only evoke the following tools in this order.
  1. Editor: Modify your Verilog
  2. Generate: Build  the Top Level Design
  3. Program FPGA: Program Device
Case 2

Lets consider what we need to do if we want to add some more IO. Lets add the OR function back assigning it to LED2. Open the Verilog file myandor and add the assignment for LED 2. The Verilog should look something like this.

module myandor (

input[1:0] SW,
output wire [2:0] LED
             );        

assign LED[0] = SW[0] & SW[1]; //And
assign LED[1] = SW[0] ^ SW[1]; //XOr
assign LED[2] = SW[0] | SW[1]; //XOR

endmodule
Save the file. Open the project design tab andor. You should notice a warning associated with myandor symbol. It will appear like this.



Since we added another LED port, the symbol will have to be updated. Right click on the symbol and select "Update Instance(s) with Latest Component".  The LED connector LED[1:0] should disconnect. Delete LED[1:0], select LED port LED[2:0], right click and promote to top level. It should look like this when you are finished.

The choice to update the instance will not be available if there is  a snytax error in your Verilog. Go back to your file and run check syntax as necessary.



Save this file and generate.

You will have to add the pin constraint for LED 2. Double click "Create/Edit IO Attributes" under Implement Design--> Compile-->Constrain Place and Route" in the Design Flow as you did above. The following window will open.


Add the appropriate pin number for LED 2. The FPGA pin numbers for the LEDs are listed at the end of this document.

As we did earlier, close this window and acknowledge the commit and save of this pin change. Close the Designer window and acknowledge the save as needed.

Now click on Program Device. 

Summary

In this case you need only evoke the following tools in this order.
  1. Editor: Modify your Verilog
  2. Generate: Build  the Top Level Design
  3. Constraint Editor: Add pn assignment
  4. Program FPGA: Program Device

Part 4: Adding a Fabric Clock

To design sequential logic we will need a clock. In this section we show you how to add a clock to the FPGA. Lets consider adding some simple logic that counts transitions of SW0. We will use a 3-bit counter to accumulate the counts and display the output on LEDs 3-5. SW1 will be used to clear the counter. You will notice that we run SW0 through a series of 2 DFFs. It is important and common practice to synchronize an asynchronous event such as a switch transition with the system clock.

Modify you myandor Verilog file to include the following code. You will have to update the myandor instance in the top level design view and connect a expanded LED connector.
module myandor (
input clk,
input[1:0] SW,
output wire [5:0] LED
             );        

assign LED[0] = SW[0] & SW[1]; //And
assign LED[1] = SW[0] ^ SW[1]; //XOr
assign LED[2] = SW[0] | SW[1]; //XOR

reg Q0, Q1, Q2;
//synchronize SW0 to the system clk with two flipflops connected in series
always@(posedge clk)
begin
Q0 <= SW[0];
Q1 <= Q0;
end

//count switch transitions
reg[2:0] count;
always@(posedge Q1)
begin
if (~SW[1])
count <=0;
else
count <= count +1;
end

assign LED[3] = ~count[0];
assign LED[4] = ~count[1];
assign LED[5] = ~count[2];
endmodule

The clock source is associated with the andor_MSS_0 instance that we previously removed. We will have to add it back to our top level design. Select andor_MSS in the Design Hierarchy window  as shown below.


Right click and select "instantiate" in andor. 

Note, selecting auto range instances   will size the window and arrange your components. 

The design pane should look like this with both instances in the design window. 


Double click on the andor_MSS_0 instance to open the MSS (microprocessor subsystem) configurator.  Once open, double click on the clock manager. 

Enable the FABCLK by checking on the box. It should look like this.


Select OK to close the clock configurator window.

We will not need the other default enabled components. Disable them by unchecking all the boxes. 

Lastly, we will not need the MSS_RESET_N system reset signal. Double click on RESET Management  box and disable " Enable Chip-level Reset" box.

With the andor_MSS tab selected, save the file. 

Select the andor tab. You will notice that the andor_MSS_0 instance indicates it needs to be updated.


Select the instance, right click and select "Update Instance(s)  with Latest Component".  You should now see the FABCLK  port on the andor_MSS_0 instance and the other ports removed.  

Select the FABCLK port and the clk input (2nd select is control and left click) of the myandor module. While holding the mouse over one of the select ports, right click and select connect. You final design should look like this.


With the andor tab selected (the above view) save the file and then generate.

You will have to add the FPGA pin for LED 3, so double click on Create/Edit IO Attributes Implement-->Compile-->Constrain Place and Route in the Design Flow window. Add the LED 3 pin and finish programing the FPGA using the procedures detailed in the previous steps. 

Testing the Design

Test your design on the kit. Hold down SW 1 and press SW 0 to reset the counter. Press SW 0 see see the counter increment. You may notice that the more than one count may occur when you press or release. . This is a consequence of mechanical switch behavior called bounce. When a mechanical switch like our pushbutton is pushed or released, it vibrates across the contact points for a few milliseconds. Electrically this produces several signal transitions. Consequently, several rising edges may occur with each press or release. The following imagine is a time trace showing a typical switch bounce. This is a consequence of pushing or releasing a switch just once.

Switch Bounce Trace

You can observe switch bounce with an oscilloscope. You will have to have to set the scope to trigger for just one trace. Refer to the Lab Instrument Introduction for more details. The switch can be probed directly as shown in the following figure.

Probing a Push Button Switch

LED, SWITCH, USER I/O Pin-out Quick Reference

Here are the pin numbers of the SmartFusion chip that are connected to the physical LED1-8, SW1,2 and user IO 1-5. The figures are specific to the kit and can be found in the kit reference manual. http://www.actel.com/documents/A2F_EVAL_KIT_UG.pdf.

Note, the LED numbering in the following figure begins with one.

LED and Pushbutton Switch FPGA Pin Numbers


USER I/O Pins. J22 at the top of the header is the header number on the physical Printed Circuit Board (PCB). It is not the location of pin J22. In fact, USER I/O 1 (pin J19) start is at that location.

User IO Pin Header FPGA Pin Numbers




User IO Header




Common Tool Flow Pitfalls

  1. The following issues will be updated as more are revealed. Check for new listings.
  2. If you do not explicitly make FPGA pin assignments to your high level ports, Libero will assign arbitrary FPGA pin assignments to the ports.
  3. If you select "Clean and Run All" by right clicking on Program Device, your pin constraints will be removed and Libero will make arbitrary FPGA pin assignments to the ports.
  4. The Design Flow window can take a few seconds to update after you make a change. For example, if you make a change to one of your source files the dependent  Implementations such as Synthesis and Place and Route should change from a completed process (green check mark) to incomplete process (yellow triangle with exclamation) indicating the source files are out of date with the current implementation. 
  5. Sometimes the pin assignments seems to change. It is prudent to check these if you  design mysteriously stops working. If this happens, all the pin assignments should change.
  6. Generally, the project (top level view) should always be the declared as the ROOT. If it is one of the instances in the project, it will not work or the porting will not work.