WB_INTERFACE - Custom Wishbone Interface

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Figure 1. WB_INTERFACE - Custom Wishbone Interface.

The Custom Wishbone Interface component (WB_INTERFACE) enables you to build a custom Wishbone peripheral in a design, extending your 32-bit FPGA systems through the creation of custom FPGA logic.

The Custom Wishbone Interface component has a fully configurable interface for transferring data to/from connected logic, and a Wishbone bus to interface with a host processor. The individual units of this configurable interface are referred to as 'items'. The interface can include a combination of one or more of the following items:

  • Internal Registers – which allow values to be read from, and/or written to, connected logic.
  • Command Sets – which allow operations to be enabled on connected logic.
  • External Address Ranges – which allow access to blocks of addresses on connected logic.

Customization is performed through configuration dialogs associated with the component, after placement on the OpenBus System or Schematic document.

In addition to making the task of building custom Wishbone peripherals far easier, the Custom Wishbone Interface component also provides the ability to generate C code based on the items specified in the interface – simplifying interaction with the component from the embedded code running on the host processor.

Features at-a-glance

  • Fully customizable Wishbone peripheral component
    • Configurable interface to connected custom logic
    • Wishbone interface to host processor
  • Supports 3 interface item types:
    • Internal Registers
    • Command Sets
    • External Address Ranges
  • Completely configurable from the OpenBus System document or Schematic sheet
  • Requires no knowledge of Wishbone bus or HDL to use
  • Ability to generate C code for use in embedded projects


From an OpenBus System document, the Custom WB Interface component can be found in the Peripherals region of the OpenBus Palette panel.

From a schematic document, the WB_INTERFACE component can be found in the FPGA Peripherals (Wishbone) integrated library (FPGA Peripherals (Wishbone).IntLib), located in the \Library\Fpga folder of the installation.

Designing with the WB_INTERFACE

Use the following links to explore use of the WB_INTERFACE in more detail:

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