DSP Builder for Intel® FPGAs (Advanced Blockset): Handbook

ID 683337
Date 12/12/2022

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Document Table of Contents Modifying Avalon Streaming Blocks

Avalon Streaming blocks are Simulink masked subsystem. You can look under the mask to see their implementation. You can also modify Avalon streaming blocks to add more ports, remove existing ports or specify additional interface properties.


  1. To modify these blocks, you must first create your own copy of the block by breaking the link to the library block. See Simulink documentation for more information.
  2. Add more ports to Avalon Streaming blocks by connecting these ports internally in the same way as the existing signals, for example, by connecting the ports with FIFO buffers.
    1. Assign a unique and valid port role for new ports. You can assign a role by right clicking on the Simulink port block and then selecting Properties.
    2. In the Tag field enter the role name you wish to assign to that port (refer to Tagging a new Avalon Streaming port with the role.
      Figure 35. Tagging a new Avalon Streaming port with the roleThe figure shows the role name for the sink_error port is error.The Avalon interface requires that every port in the interface must have a unique role. So for example, you cannot have two ports with the role of data.
  3. Specify additional interface properties by right clicking on the masked subsystem and select Properties and enter any commands in the Description field. DSP Builder writes out the text you enter verbatim to the hw.tcl file, so you must ensure that it is correct.
  4. Ensure when you edit the mask do not edit the Type field in the Mask Editor, as DSP Builder uses the Type field to identify subsystems that define interfaces.