Vitis Model Composer Hub - 2025.2 English - UG1483

Control implementation of the model.

Description

The Vitis Model Composer Hub block controls the behavior of the Vitis Model Composer tool.

You can specify the targeted design flow for the generated output, the output directory path, the desired device, and design clock frequency using the following tabs.

• The Hardware Selection pane helps with device or board selection.
• The Code Generation pane provides tabs to take the design through an elaboration workflow of analysis, validation on hardware, and export out of Vitis Model Composer. Different options display depending on whether the subsystem is targets HDL, HLS, or AIE.
• The Design Settings pane provides miscellaneous settings for the design.

Library

AI Engine/Tools; HLS/Tools; Utilities/Code Generation.

Data Type Support

Data type support is not applicable to the Vitis Model Composer Hub block.

Parameters

The following section describes the configurable options available in each pane of the Vitis Model Composer Hub block.

Hardware Selection

Clicking the browse button (…) displays the Device Chooser dialog box. This allows you to select a target part, board, or platform. Vitis Model Composer obtains board and device data from the Vivado database.

Code Generation

Select the subsystem name for which to generate code from the list on the left. Different settings display depending on the type of code generation (HDL, HLS, or AI Engine) selected.

Settings (AIE)

AIE Compiler Options

Provides the ability to pass additional command line options (debug options, execution target options etc.) to the AIE Compiler.

Analyze (AIE)

Target Directory

Specifies the work directory for performing the actions on this tab.

AIE Simulator Options

Provides the ability to pass additional command line options to the AIE Simulator.

Simulation timeout (cycles)

When enabled, it specifies the number of cycles for which AIE simulation runs. The default value is 50000.

Collect profiling statistics and enable 'printf' for debugging

When enabled, this option allows collection of profiling data for analysis.

Collect trace data for Vitis Analyzer, viewing internal signals, and latency

When enabled, this option collects trace data for signals within the AI Engine design to be viewed in Vitis Analyzer or the Simulation Data Inspector.

View AIE Simulation output and throughput

Opens the Simulation Data Inspector to plot outputs of the AI Engine subsystem as simulated by the AIE Simulator.

Open Vitis Analyzer

Click to invoke the Vitis Analyzer tool. This option is only enabled after AI Engine Simulation has been run at least once after enabling.

Settings (HDL)

Target Language

Specifies the HDL language to be used for compilation of the design. The possibilities are VHDL and Verilog.

VHDL library

Specifies the name of VHDL work library for code generation. The default name is xil_defaultlib.

Use STD_LOGIC type for Boolean or 1 bit wide gateways

If your design's Hardware Description Language (HDL) is VHDL, selecting this option declares a Boolean or 1-bit port (Gateway In or Gateway Out) as a STD-LOGIC type. If this option is not selected, Vitis Model Composer interprets Boolean or 1-bit ports as vectors.

Note: When you enable this option and try to run Generate code and Run behavioral simulation in Vivado, the elaboration phase can fail.

Synthesis Strategy

Choose a Synthesis strategy from the pre-defined strategies in the drop-down menu.

Implementation Strategy

Choose an Implementation strategy from the pre-defined strategies in the drop-down menu.

Enable multiple clocks

Must be enabled when the design has multiple clocks. This indicates to the code generation engine that it must obtain the clock information for the various subsystems from the respective clock tabs. If not enabled, then the design is treated as a single clock design.

Number of clocks

Defines the number of clocks in the design. The number of clock tabs that appear is equivalent to the number of clocks. In each clock tab, you must select the subsystem and configure the clock settings of that subsystem.

FPGA clock period (ns)

Defines the period in nanoseconds of the system clock. The value need not be an integer. The period passes to the AMD implementation tools through a constraints file, where it serves as the global PERIOD constraint. Multicycle paths are constrained to integer multiples of this value.

Simulink system period (sec)

Defines the Simulink System Period, in units of seconds. The Simulink system period is the greatest common divisor of the sample periods that appear in the model. Sample periods are set explicitly in the block dialog boxes. They are inherited according to Simulink's propagation rules, or implied by a hardware oversampling rate in blocks with this option. In the final case, the implied sample time is in fact faster than the observable simulation sample time for the block in Simulink. In hardware, a block having an oversampling rate greater than one processes its inputs at a faster rate than the data. For example, a sequential multiplier block with an over-sampling rate of eight implies a (Simulink) sample period that is one eighth of the multiplier block’s actual sample time in Simulink. You can only modify this parameter in a master block.

Clock pin location

Defines the pin location for the hardware clock. This information passes to the AMD implementation tools through a constraints file. Do not specify this option if the Vitis Model Composer design is to be included as part of a larger HDL design.

Provide clock enable clear pin

This instructs Vitis Model Composer to provide a ce_clr port on the top-level clock wrapper. The ce_clr signal resets the clock enable generation logic. The ability to reset clock enable generation logic allows designs to have dynamic control for specifying the beginning of data path sampling. This signal is important for modules that are implemented in a DFX platform.

Analyze (HDL)

Note: For more information about the tasks available on this tab, refer to Performing Analysis in Vitis Model Composer.

Target Directory

Specifies the work directory for performing the actions on this tab.

Perform Analysis

Specifies whether an analysis (timing or resource) is performed on the Vitis Model Composer design when it is compiled. If None is selected, no timing analysis or resource analysis is performed. If Post Synthesis is selected, the analysis will be performed after the design has been synthesized in the Vivado toolset. If Post Implementation is selected, the analysis is performed after the design is implemented in the Vivado toolset.

Analysis Type

Two selections are available: Timing or Resource. After generation is completes, a Timing Analyzer table or Resource Analyzer table launches.

Block Icon Display

Specifies the type of information to be displayed on each block icon in the model after compilation is complete. The display options are as follows.

Default

Displays the default block icon information on each block in the model. A block’s default icon is derived from the xbsIndex library.

Figure 2. Default Block Icon

Normalized Sample Periods

Displays the normalized sample periods for all the input and output ports on each block. Higher values indicate slower sample rates. For example:

• If the Simulink System Period is set to 4 and the sample period propagated to a block port is 4, then the normalized period for the block port is 1.
• If the period propagated to the block port is 8 then the normalized sample period is 2.

Figure 3. Normalized Sample Periods Icon

Sample frequencies (MHz)

Displays sample frequencies for each block.

Pipeline stages

Displays the latency information from the input ports of each block. The displayed pipeline stage might not be accurate for certain high-level blocks such as the FFT, RS Encoder/Decoder, Viterbi Decoder, etc. In this case, you can use the displayed pipeline information to determine whether a block has a combinational path from the input to the output. For example, the Up Sample block in the following figure shows that it has a combinational path from the input to the output port.

Figure 4. Pipeline Stages

HDL port names

Displays the HDL port name of each port on each block in the model.

Input data types

Displays the data type of each input port on each block in the model.

Output data types

Displays the data type of each output port on each block in the model.

Update the model

Update the model to display the selected Block Icon type.

Create interface document

When you select this checkbox and activate Generate for netlisting, Vitis Model Composer creates an HTM file that describes the netlisted design. This document is placed in a documentation subfolder under the netlist folder.

Settings (HLS)

FPGA clock frequency

Specifies the clock frequency in MHz for the targeted device. This frequency passes to the downstream tool flow.

Testbench stack size (MBytes)

This parameter prompts you to enter a larger stack size. When you enable Create and run testbench, the Testbench stack size option specifies the size of the test bench stack frame during C simulation (CSIM). Occasionally, the default stack frame size of 10 MB allocate for execution of the test bench is insufficient to run the test. This can be due to allocation of large arrays on the stack and/or deep nesting of subsystems. Typically, if this happens, the test fails with a segmentation fault and an associated error message. For such cases you can increase the size of the stack frame and rerun the test.

Analyze (HLS)

Target Directory

Specifies the work directory for performing the actions on this tab.

Validate on Hardware

Target Directory

Specifies the work directory for performing the actions on this tab.

HW System Type

Choose between Baremetal or Linux hardware validation flow.

Target

Specify the target for hardware validation flow.

Common SW Dir

Provide the path to the folder containing the PetaLinux common images. This option is only available when you select a Linux HW System Type.

Target SDK Dir

Provide the path to the folder containing the target SDK. This option is only available when you select a Linux HW System Type.

Generate (BOOT.BIN/SD card image) after code generation

When you enable this option, a BOOT.BIN (for baremetal HW system) or SD card image (for Linux HW system) generates after code generation.

Export

Export Directory

Specifies the directory where the export products are created.

Export Type

IP Catalog

Export HDL or HLS subsystem as a Vivado IP. When you select IP Catalog, the Settings (...) button displays a dialog box. This allows you to add a description of the IP to be placed in the IP catalog.

Synthesized Checkpoint

Export HDL subsystem as a Synthesized Checkpoint for use in Vivado.

HDL Netlist

Export HDL subsystem as HDL code and netlist for use in Vivado.

Vitis HLS

Export HLS subsystem as HLS C/C++ code.

Vitis Subsystem

Export HDL, AIE, HLS or heterogeneous subsystem as a Vitis Subsystem (VSS).

A Vitis Subsystem (VSS) is a platform-independent reusable design component with customizable AI Engine and PL content. The VSS integrates into a larger system through Vitis tools. For more information, see Linking a VSS Component.

Graph Code

Export AIE subsystem as AI Engine graph code.

Generate testbench

HDL designs

This instructs Vitis Model Composer to create an HDL test bench. Simulating the test bench in an HDL simulator compares Simulink simulation results with ones obtained from the compiled version of the design. To construct test vectors, Vitis Model Composer simulates the design in Simulink, and saves the values seen at gateways. The top HDL file for the test bench is <name>_testbench.vhd/.v, where <name> derives from the portion of the design being tested.

Note: Test bench generation does not support designs with Gateway In or Gateway Out blocks configured as AXI4-Lite interfaces.

AIE/HLS designs

When enabled, Vitis Model Composer generates the test vectors while generating the code.

Design Settings

Treat this model as a legacy System Generator design for backward-compatibility

Specify whether the Model Composer Hub block treats your model as a legacy System Generator design. When you automatically upgrade a System Generator token to the Model Composer Hub block, this check box is automatically enabled. When you enable this check box, you can use the Model Composer Hub block without requiring changes to your legacy designs. However, newer capabilities provided by the Model Composer Hub block, such as the Validate on Hardware Flow, are not available.

Number of parallel AI Engine builds

To speed up model compilation, Vitis Model Composer can build the AI Engine blocks in parallel, taking advantage of multiple cores on your machine. You can increase this value up to the maximum number of cores on your machine.