AN 845: Signal Tap Tutorial for Intel Arria 10 Partial Reconfiguration Design

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AN-845 | 2018.10.08

Tutorial Overview

This document demonstrates how to debug an Intel^® Arria^® 10 Partial Reconfiguration design with the Signal Tap Logic Analyzer. This application note extends the Partial Reconfiguration (PR) work presented on AN 797: Partially Reconfiguring a Design on Intel^® Arria^® 10 GX FPGA Development Board to a verification environment.

The Signal Tap Logic Analyzer captures and displays real-time signal behavior in an FPGA design, allowing to examine the behavior of internal signals during normal device operation without the need for extra I/O pins or external lab equipment.

Partial Reconfiguration is an advanced design flow that allows you to reconfigure a portion of the FPGA dynamically, while the remaining FPGA design continues to function. You can define multiple personas to occupy the same design region, without impacting operation in other regions.

The PR support in the Signal Tap Logic Analyzer includes data acquisition in static and PR regions. Moreover, you can debug multiple personas present in a PR region and multiple PR regions.

PR Debug Considerations

Debugging a PR design requires planning. Before compiling, you must decide whether you want to tap signals in the static region, which PR region you want to debug, and which personas in the PR region you want to debug.

To ensure visibility, the debugging fabric must extend to all the regions that you want to tap. The Intel^® Quartus^® Prime software performs this extension with debug bridge components: the SLD JTAG Bridge Agent Intel^® FPGA IP and the SLD JTAG Bridge Host Intel^® FPGA IP.

To incorporate these components to the design, for each PR region in the design that you want to debug:

Instantiate the SLD JTAG Bridge Agent in the static region.
Instantiate the SLD JTAG Bridge Host in the PR region of the default persona.
Instantiate the SLD JTAG Bridge Host on the implementation revisions that you want to debug.

Figure 1. Debug Fabric in PR Design with Signal Tap The figure shows in solid outline the entities that you instantiate manually, and in dashed outline the entities that the Compiler instantiates.

SLD JTAG Bridge Index

The index is an attribute of the SLD JTAG Bridge Agent that uniquely identifies bridge agents present in the design. You can find information regarding the bridge index in the synthesis report (<base revision>.syn.rpt), by looking under JTAG Bridge Agent Instance Information. The bridge index for the root partition is always None.

Figure 2. JTAG Bridge Agent Instance Information in Synthesis Report

Tutorial Software and Hardware Requirements

To perform this tutorial, you need the following software and hardware:

The Intel^® Quartus^® Prime Pro Edition software version 18.1 or later. The software includes the Signal Tap Logic Analyzer and the Programmer.
Intel^® Arria^® 10 GX FPGA development kit, or a design board with JTAG connection to the device under test.
Intel^® FPGA Download Cable, for communication between the device and the Intel^® Quartus^® Prime software.

Tutorial Design Description

The design for this tutorial consists of one 32-bit counter. At the board level, the design connects the clock to a 50MHz source, and connects the output to four LEDs on the FPGA. Selecting the output from the counter bits in a specific sequence causes the LEDs to blink at a specific frequency.

Figure 3. Flat Reference Design without PR Partitioning

Downloading the Tutorial Design

The partial reconfiguration tutorial files are available in:

https://github.com/intel/fpga-partial-reconfig

To download the tutorial:

In the web page, click Clone or download, and then click Download ZIP.
Unzip the fpga-partial-reconfig-master.zip file.
Navigate to the tutorials/a10_pcie_devkit_blinking_led_stp sub-folder to access the design.

Tutorial Design Files

The design folder contains two subfolders: The start folder contains the files that you need to follow this tutorial, and the finish folder contains the complete set of files you create using this application note. Reference these files at any point during the walkthrough.

Table 1. Description of Tutorial Design Files in start Folder
File Name	Description
top.sv	Top-level file. Contains the flat implementation of the design. This module instantiates the `blinking_led` sub-partition and the `top_counter` module. This module also instantiates the SLD JTAG Bridge Agent for debugging purposes.
top_counter.sv	Top-level 32-bit counter that controls `LED[1]` directly. The registered output of the counter controls `LED[0]`, and powers `LED[2]` and `LED[3]` via the `blinking_led` module.
blinking_led.sdc	Defines the timing constraints for the project.
blinking_led.sv	This module acts as the PR partition. The module receives the registered output of `top_counter` module, which controls `LED[2]` and `LED[3]`.This module also instantiates the SLD JTAG Bridge Agent for debugging the default persona.
blinking_led.qpf	Intel^® Quartus^® Prime project file that contains a list of all the revisions in the project.
blinking_led.qsf	Intel^® Quartus^® Prime settings file that contains assignments and settings for the base revision of the project.
blinking_led_default.qsf	Contains assignments and settings for the `blinking_led_default` implementation revision of the project.
blinking_led_slow.qsf	Contains assignments and settings for the `blinking_led_slow` implementation revision of the project.
blinking_led_empty.qsf	Contains assignments and settings for the blinking led empty of the project.
blinking_led_slow.sv	Slower version of the PR logic. On this version, the led blinks at a slower rate than the default PR persona. The module receives the registered output of top_counter module, which controls LED[2]and LED[3]. This module also instantiates the SLD JTAG Bridge Agent for debugging the default persona.
blinking_led_empty.sv	Empty version of the PR logic. This module holds the outputs at a constant. The module receives the registered output of top_counter module, which controls LED[2] and LED[3]. This module also instantiates the SLD JTAG Bridge Agent for debugging the default persona.
pr_ip.ip	Intel^® Arria^® 10 Partial Reconfiguration Controller IP. This Intel^® FPGA IP enables PR over a JTAG connection.

The following Figure shows the list of files in the finish folder:

Figure 4. Tutorial Design Files in finish Folder

Tutorial Walkthrough

This tutorial describes preparing the blinking_led design for debug with the Signal Tap Logic Analyzer.

Note: This Application Note only covers adding Signal Tap debugging capabilities to a PR design. For information about turning a non-PR design to PR, refer to AN 797: Partially Reconfiguring a Design on Intel^® Arria^® 10 GX FPGA Development Board .

Process Description

To tap signals in a PR design, you extend the debug fabric to the PR regions when creating the base revision, and then define debug components for the implementation revisions.

Tutorial Steps

This tutorial includes the following steps:

Step 1: Getting Started
Step 2: Preparing the Base Revision
Step 3: Preparing the Implementation Revisions for Debug
Step 4: Tapping Signals in the Implementation Persona
Step 5: Configuring Data Acquisition
Step 6: Setting Trigger Conditions
Step 7: Generating Programming Files
Step 8: Programming the Board
Step 9: Performing Data Acquisition

Step 1: Getting Started

To copy the reference design files to your working environment and compile the initial design for this tutorial:

Before you begin, download the tutorial files.
In your working environment, create a directory named a10_pcie_devkit_blinking_led_stp.
Copy the downloaded tutorials/a10_pcie_devkit_blinking_led_stp/start sub-folder to your working directory.
In the Intel^® Quartus^® Prime Pro Edition software, click File > Open Project and select blinking_led.qpf.
Click Processing > Start > Start Analysis and Synthesis.

Step 2: Preparing the Base Revision

This step extends the debug fabric to the PR regions that you want to debug. To accomplish this goal, you must instantiate the SLD JTAG Bridge Agent in the static region and the SLD JTAG Bridge Host in the default persona of the PR region.

Preparing the Static Region

In the IP Catalog (Tools > IP Catalog), type SLD JTAG Bridge Agent, and double-click the SLD JTAG Bridge Agent Intel^® FPGA IP .
In the Create IP Variant dialog box, type sld_agent as the file name, and then click Create.

Figure 5. Create IP Variant Dialog Box
In the parameter editor, use the default parameterization for sld_agent. Click Generate HDL..., and then click Generate.

Figure 6. SLD JTAG Bridge Agent Intel^® FPGA IP Parameters

The parameter editor generates the sld_agent.ip IP variation file and adds the file to the blinking_led project.
Close the parameter editor.
Verify whether the sld_agent IP variant appears in the IP Components tab of the Project Navigator.

Figure 7. sld_agent IP Variant in Project Navigator

If the IP variant does not appear in the Project Navigator, click Project > Add/Remove Files in Project, find the sld_agent.ip file, and add to the project.

In the top.sv file, instantiate the sld_agent IP in the base revision by uncommenting the following lines:

//===============
//Enable Signal Tap
wire tck;
wire tms;
wire tdi;
wire vir_tdi;
wire ena;
wire tdo;
sld_agent u_sld_agent (
    .tck	(tck),	//  output,  width = 1, connect_to_bridge_host.tck
    .tms	(tms),	//  output,  width = 1,                       .tms
    .tdi	(tdi),	//  output,  width = 1,                       .tdi
    .vir_tdi(vir_tdi),	//output,  width = 1,                 .vir_tdi
    .ena	(ena),	//  output,  width = 1,                       .ena
    .tdo	(tdo)	 //   input,  width = 1,                       .tdo
);
//===============

Preparing the Default PR Persona

In this phase you instantiate the SLD JTAG Bridge Host in the PR region that you want to debug.

In the IP Catalog (Tools > IP Catalog), type SLD JTAG Bridge Host, and double-click the SLD JTAG Bridge Host Intel^® FPGA IP .
In the Create IP Variant dialog box, type sld_host as the file name, and then click Create.

Figure 8. Create IP Variant Dialog Box
In the parameter editor, leave the default parameterization for sld_host. Click Generate HDL..., and then click Generate.

Figure 9. SLD JTAG Bridge Host Intel^® FPGA IP Parameters

The parameter editor generates the sld_host.ip IP variation file and adds the file to the blinking_led project.
Close the parameter editor.
Verify whether the sld_host IP variant appears in the IP Components tab of the Project Navigator.

Figure 10. sld_host IP Variant in Project Navigator

If the IP variant does not appear in the Project Navigator, click Project > Add/Remove Files in Project, find the sld_host.ip file, and add it to the project.

Instantiate the sld_host IP in the default persona by uncommenting the following blocks of code from blinking_led.sv:

//===============
//Uncomment to enable Signal Tap
wire tck;
wire tms;
wire tdi;
wire vir_tdi;
wire ena;
wire tdo;
sld_host u_sld_hostled_two_on (
   .tck	(tck),	//   input,  width = 1, connect_to_bridge_host.tck
   .tms	(tms),	//   input,  width = 1,                       .tms
   .tdi	(tdi),	//   input,  width = 1,                       .tdi
   .vir_tdi(vir_tdi),//   input,  width = 1,                    .vir_tdi
   .ena	(ena),	//   input,  width = 1,                       .ena
   .tdo	(tdo)	 //  output,  width = 1,                       .tdo
);
//===============

Change the instantiation of the persona in top.sv to include the sld_host ports.

blinking_led u_blinking_led (
    .clock         (clock),
    .counter       (count_d),
    //===================
    //Uncomment this block to enable Signal Tap
    .tck	(tck),	//   input,  width = 1, connect_to_bridge_host.tck
    .tms	(tms),	//   input,  width = 1,                       .tms
    .tdi	(tdi),	//   input,  width = 1,                       .tdi
    .vir_tdi(vir_tdi), // input,  width = 1,                   .vir_tdi
    .ena	(ena),	//   input,  width = 1,                       .ena
    .tdo	(tdo),	//  output,  width = 1,                       .tdo
    //====================
    .led_two_on    (pr_led_two_on),
    .led_three_on  (pr_led_three_on)
);

Update the port definition of the default PR persona to include the following ports by uncommenting this block of code in the blinking_led.sv file:

module blinking_led (
    // clock
    input wire clock,
    input wire [31:0] counter,
    //=================
    //Uncomment this block to enable Signal Tap
    input wire tck,
    input wire tms,
    input wire tdi,
    input wire vir_tdi,
    input wire ena,
    output wire tdo,
    //=================
    // Control signals for the LEDs
    output wire led_two_on,
    output wire led_three_on
);

Step 3: Preparing the Implementation Revisions for Debug

In this step you instantiate the SLD JTAG Bridge Host and then add a .stp file to the implementation revisions that you want to debug.

In the Intel^® Quartus^® Prime GUI, set blinking_led_slow as the current revision.
Include sld_host.ip as a project file in the blinking_led_slow implementation revision.

Uncomment the following blocks of code from blinking_led_slow.sv:

//===================
// Uncomment this block to enable Signal Tap
input wire tck,
input wire tms,
input wire tdi,
input wire vir_tdi,
input wire ena,
output wire tdo,
//===================
//===================
// Uncomment this block to enable Signal Tap
sld_host u_sld_hostled_two_on (
	.tck	(tck),	//   input,  width = 1, connect_to_bridge_host.tck
	.tms	(tms),	//   input,  width = 1,                       .tms
	.tdi	(tdi),	//   input,  width = 1,                       .tdi
	.vir_tdi(vir_tdi),//   input,  width = 1,                    .vir_tdi
	.ena	(ena),	//   input,  width = 1,                       .ena
	.tdo	(tdo)	//  output,  width = 1,                       .tdo
);
//===================

Update the port definition for the PR personas to include the following ports, by uncommenting this block of code in blinking_led_slow.sv and blinking_led_empty.sv files:

module blinking_led_slow (
    // clock
    input wire clock,
    input wire [31:0] counter,
    //=================
    //Uncomment this block to enable Signal Tap
    input wire tck,
    input wire tms,
    input wire tdi,
    input wire vir_tdi,
    input wire ena,
    output wire tdo,
    //=================
    // Control signals for the LEDs
    output wire led_two_on,
    output wire led_three_on
);

Click Tools > Signal Tap Logic Analyzer to open the Signal Tap Logic Analyzer Window.

Figure 11. Signal Tap Logic Analyzer Window
Click File > Save As, and save the file as stp_slow.stp.
A dialog box appears prompting you to enable Signal Tap file stp_slow.stp for the current project.
Figure 12. Enable stp_slow.stp for the Current Project
Click Yes.

Repeat these steps for the blinking_led_default and the blinking_led_empty personas. Use stp_default.stp and stp_empty.stp for the Signal Tap files.

You can disable Signal Tap in the project by clicking Assignments > Settings. In the Category pane select Signal Tap Logic Analyzer. Then, turn off Enable Signal Tap Logic Analyzer.

Step 4: Tapping Signals in the Implementation Persona

To add signals from the implementation persona to the Signal Tap logic analyzer:

Set blinking_led_slow as the current revision in the Intel^® Quartus^® Prime GUI.
Open the stp_slow.stp file.
Double-click the Setup tab to open the Node Finder.

Set the following search fields, and then click Search

Field	Value
Named	*
Filter	Signal Tap: pre-synthesis
Look in	top\|u_blinking_led

Figure 13. Search Parameters to Find Signals

This action displays all the nodes that you can probe in this revision.

From the Matching Nodes list, select led_three_on, led_two_on, and counter[2:0], counter[27], and counter[23], and then click >.
This action adds the signals to the Nodes Found list.
Figure 14. Signals in Nodes Found List
Click Insert.

The signals now appear in the Instance Manager pane of the Signal Tap GUI.

Step 5: Configuring Data Acquisition

You specify the acquisition parameters in the Signal Configuration pane of the Signal Tap Logic Analyzer.

Figure 15. Signal Configuration Pane

Add Acquisition Clock

Specify the reference clock that Signal Tap uses during acquisition.

Perform the following steps in the Signal Configuration pane:

Next to Clock, click … to open the Node Finder.

Set the following search parameters:

Field	Value
Named	*
Look in	top\|u_blinking_led

Figure 16. Search Parameters to Find the Clock

Click Search.

Figure 17. Select Clock in Node Finder
Select clock, click >, and then click OK.

Add Storage Parameters

Storage parameters define the number of samples the Signal Tap Logic Analyzer captures and stores, how to organize this samples, and the location of the sample with respect to the trigger activation.

In Sample Depth, select 128.
In Storage Qualifier, set Type as Continuous.
In Trigger Position, select Center Trigger Position.

Figure 18. Acquisition Settings for Tutorial

Step 6: Setting Trigger Conditions

These steps direct the Signal Tap Logic Analyzer to record data only after u_blinking_led|led_three_on or u_blinking_led|led_two_on does a rising edge transition.

In the Setup tab of the Signal Tap Logic Analyzer window, turn on the box under the Trigger Condition column
Open the drop-down menu and select Basic OR.
For u_blinking_led|led_three_on and u_blinking_led|led_two_on, turn on Trigger Enable and select Rising Edge as the trigger type.
For all the other signals, turn off Trigger Enable.

Figure 19. Trigger Conditions

Defining trigger conditions completes the Signal Tap instance configuration. Now you can compile the design.

Step 7: Generating Programming Files

The design is now ready for compilation. The Intel^® Quartus^® Prime Compiler generates files that you then program into the FPGA. This Partial Reconfiguration design requires generating .sof and .rbf files.

Ensure the blinking_led.qsf contains the following assignments:
```
set_global_assignment -name GENERATE_PR_RBF_FILE ON
set_global_assignment -name ON_CHIP_BITSTREAM_DECOMPRESSION OFF
```
These assignments allow the assembler to automatically generate the required PR bitstreams.
In the Intel^® Quartus^® Prime GUI, click Processing > Start Compilation to compile the base revision.
Alternatively, type the following command:
```
quartus_sh --flow compile blinking_led -c blinking_led
```

Compile the implementation revision:

quartus_sh --flow compile blinking_led –c blinking_led_slow
quartus_sh --flow compile blinking_led –c blinking_led_default
quartus_sh --flow compile blinking_led –c blinking_led_empty

If the compilation succeeds, the output files are now in the output_files directory.

Step 8: Programming the Board

Before you begin:

Connect the power supply to the Intel^® Arria^® 10 GX FPGA development board.
Connect the USB Blaster cable between your PC USB port and the USB Blaster port on the development board.

Note: This tutorial utilizes the Intel^® Arria^® 10 GX FPGA development board on the bench, outside of the PCIe* slot in your host machine.

To program the design on the board:

In the Intel^® Quartus^® Prime software, click Tools > Programmer.
In the Programmer, click Hardware Setup and select USB-Blaster.
Click Auto Detect and select the device, 10AT115S2F45 .
Click OK. The Intel^® Quartus^® Prime software detects and updates the Programmer with the three FPGA chips on the board.
Select the 10AT115S2F45 device, click Change File and load the blinking_led.sof file.
Enable Program/Configure for blinking_led.sof file.
Click Start and wait for the progress bar to reach 100%.
To program the PR persona that you want to debug, right-click the blinking_led.sof file in the Programmer, and click Add PR Programming File.
Select the blinking_led_slow.pr_partition.rbf file.
Disable Program/Configure for blinking_led.sof file.
Enable Program/Configure for blinking_led_slow.pr_partition.rbf file and click Start.
On the board, verify that two of the LEDs are blinking slower than the other two.

Step 9: Performing Data Acquisition

After loading the appropriate .rbf onto the board, you can start data acquisition on the Signal Tap logic analyzer.

To perform data acquisition:

Make sure that the Signal Tap Logic Analyzer loads the .stp file in the current active revision.

In the top right corner of the Signal Tap window, set up the JTAG connection to the board with the following options:

Option	Description
Hardware	USB-BlasterII
Device	10AT115S
Bridge Index	0

Figure 20. JTAG Configuration

On the Signal Tap toolbar, click Run Analysis .
The analysis may take a few minutes.

When the analysis finishes, the Signal Tap Logic Analyzer loads the waveforms to the window.

The following section displays the resultant waveforms for all PR configurations.

Tutorial Results

By looking at the data acquisition waveform, you can verify whether the signals behave consistently with your expectations. As a reference, the waveforms include counter[2:0] signals.

Waveforms for Slow Implementation

In the Figure, signals led_three_on and led_two_on show a rising edge one clock cycle after counter[27] has a rising edge.

Figure 21. Slow Implementation

Waveforms for Default Implementation

Figure 22. Default Implementation

Waveforms for Empty Implementation

Figure 23. Empty Implementation

Document Revision History for AN 845: Signal Tap Tutorial for Intel Arria 10 Partial Reconfiguration Design

This document has the following revision history:

Table 2. Document Revision History
Document Version	Intel^® Quartus^® Prime Version	Changes
2018.10.08	18.1.0	Updated contents with the new PR flow, which eliminates the need for manual export of finalized snapshot of the static region. Updated the list of files in the start and finish folders.
2018.05.07	18.0.0	Initial release.