Connecting Blocks - 2024.1 English

Vitis Model Composer User Guide (UG1483)

Document ID
UG1483
Release Date
2024-05-30
Version
2024.1 English

You can connect the output ports on blocks to the input ports of other blocks with signal lines. Signal lines define the flow of data through the model. Signals can have several attributes:

Data type
Defines the type of data carried by the signal. Values can range from integer, to floating point, to fixed point data types. See Working with Data Types for more information.
Signal dimension
Defines the values as being scalar, vector, or matrices. See Signal Dimensions and Matrices, Vectors, and Scalars for more information.
Complexity
Defines a value as being a complex or real number. See Signal Values for more information. The following figure shows complex numbers propagating through a model.
Figure 1. Complex Signal Values

To add a signal line, position the cursor over an input or output port of a Simulink block. The cursor changes to a cross hair (+). Left-click and drag the mouse away from the port. While holding down the mouse button, the connecting line appears as a dotted line as you move across the design canvas. The dotted line represents a signal that is not completely connected.

Release the mouse button when the cursor is over a second port to be connected. If you start with an input port, you can stop at an output port, or connect to another signal line; if you start at an output you can stop at an input. Simulink connects the ports with a signal line and an arrow indicating the direction of signal flow.

You can connect into an existing line by right-clicking and dragging the mouse. This creates a branching line connected to the existing signal line at the specified location. The branch line can connect to an input or output as appropriate to the connected signal.

Tip: You can also connect blocks by selecting them sequentially while holding the Ctrl key. This connects the output of the first block into the input of the second block. Keeping the Ctrl key pressed and selecting another block continues the connection chain.
Simulink updates the model when you run simulation by clicking Run Simulation. You can also update the model using the Simulation > Update Diagram menu command, or by typing Ctrl+D at any point in the design process. You will see the Data Types, Signal Dimensions and Sample Times from the source blocks propagate through the model.
Tip: You can use the Display > Signals and Ports menu command to enable the various data that you want displayed in your model, such as Signal Dimensions and Port Data Types.

You cannot specify sample times on HLS Library blocks, except for the Constant block from the Source library of the HLS library. Model Composer infers the sample time from the source blocks connected at the input of the model, and does not support multiple sample times in the Model Composer design.

By updating the diagram from time to time, you can see and fix potential design issues as you develop the model. This approach can make it easier to identify the sources of problems by limiting the scope to recent updates to the design. The Update Diagram is also faster than running simulation.