Bus Selector

Select elements from incoming bus

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Libraries:
Simulink / Commonly Used Blocks
Simulink / Signal Routing
HDL Coder / Signal Routing

Description

The Bus Selector block outputs the elements you select from the input bus. The block can output the selected elements separately or in a new virtual bus.

The Bus Selector block does not support mixing message and signal elements as outputs.

Examples

Simplify Bus Interfaces in Subsystems and Models

Convert a subsystem or model interface that uses Inport, Bus Selector, Bus Creator, and Outport blocks to use In Bus Element and Out Bus Element blocks.

Open Model

Explore Simulink Bus Capabilities

Work with buses in components, use bus ports at component interfaces, and perform common bus workflows faster.

Open Model

Ports

Input

Port_1 — Input virtual or nonvirtual bus

bus

The input virtual or nonvirtual bus contains the elements to be selected.

For arrays of buses, use a Selector block to select the bus that you want to use with the Bus Selector block.

Data Types: single | double | half | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | string | Boolean | fixed point | enumerated | bus
Complex Number Support: Yes

Output

Port_1 — Selected elements of input bus

scalar | vector | matrix | array | bus

By default, the block outputs each of the selected elements from a separate output port that is labeled with the corresponding bus element name. When the Output as virtual bus parameter is enabled, the block outputs the selected elements from one port, grouped in a virtual bus.

Data Types: single | double | half | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | string | Boolean | fixed point | enumerated | bus
Complex Number Support: Yes

Parameters

To interactively edit the block parameters, double-click the block.

Elements in the bus — List of elements in input bus

list of element names

This parameter is read-only.

The list of input elements includes all elements that enter the block, including the elements of nested buses. An arrow next to an element indicates that an input element is a bus. To display the contents of that bus, click the arrow.

To highlight the source of an element that enters the block, select the element in the list and click Find.

If you change an element name while the dialog box is open, click Refresh to update the name in the list.

Programmatic Use

Block Parameter: InputSignals

Type: cell array

Values: element names

Filter by name — Search term for filtering displayed input elements

text

To filter the displayed input elements, enter a search term. The filter does a partial-string search. Do not enclose the search term in quotation marks.

To access the filtering options, click the Show filtering options button to the right of the Filter by name box.

Enable regular expression — Option to filter displayed input elements by regular expression

off (default) | on

Select this parameter to filter the displayed input elements with either regular expressions or partial search strings. By default, you can filter the displayed input elements with only partial search strings.

Regular expressions let you filter based on whether the input elements match a pattern. For example, enter t$ in the Filter by name box to display all elements whose names end with a lowercase t (and their immediate parents). For more informations, see Regular Expressions.

Dependencies

To access this parameter, click the Show filtering options button on the right side of the Filter by name box.

Show filtered results as a flat list — Option to display filtered results as a flat list

off (default) | on

Select this parameter to display filtered results as a flat list that uses dot notation to reflect the bus hierarchy. By default, the filtered results appear in a hierarchical tree.

Dependencies

To access this parameter, click the Show filtering options button on the right side of the Filter by name box.

Selected elements — Selected elements of input bus

list of elements names

Each element in this list is included in the block output.

To add elements to the block output:

1. Select one or more elements from the Elements in the bus list.

   If you select multiple elements from the Elements in the bus list, the order in which you select them sets their order in the Selected elements list.

2. Optionally, specify where you want the elements to appear in the Selected elements list. Select the element below which you want the added elements to appear. If you do not select an element, added elements appear at the end of the list.

3. Click Select.

Alternatively, in the Simulink^® Editor, draw a new line close to the output side of the Bus Selector block when the input port receives a bus and all output ports connect to other ports. Simulink prompts you to specify an element to select and adds a port for the element you specify. You cannot create ports in this way when Output as virtual bus is selected.

To change the order of the output elements, select an element or multiple contiguous elements in the list, then click Up or Down. Port connectivity is maintained when you change the element order.

To remove elements from the block output, select the elements in the list, then click Remove.

If an element in the list is not in the input bus, the element name starts with three question marks (???). Modify the input bus to include an element of the specified name or remove the element from the list.

Limitations

To avoid a recursion limit, select fewer than 500 elements per Bus Selector block.

Programmatic Use

Block Parameter: OutputSignals

Type: character vector

Values: character vector in the form of 'signal1,signal2'

Default: none

Output as virtual bus — Option to output selected elements as virtual bus

off (default) | on

By default, the block outputs each of the selected elements from a separate output port that is labeled with the corresponding bus element name. Select this parameter to output the selected elements from one port, grouped in a virtual bus.

To convert the output to a nonvirtual bus, insert a Signal Conversion block after the Bus Selector block. Set the Signal Conversion block Output parameter to Nonvirtual bus and set the Data type to a Simulink.Bus object.

When the Selected elements list includes only one element and you enable Output as virtual bus, then that element is not wrapped in a bus. For example, if the element is a bus, the output element is that bus. If the element is not a bus, the output element is not a bus.

Programmatic Use

Block Parameter: OutputAsBus

Type: character vector

Values: 'on' | 'off'

Default: 'off'

Block Characteristics

Data Types	Boolean | bus | double | enumerated | fixed point | half | integer | single | string
Direct Feedthrough	yes
Multidimensional Signals	yes
Variable-Size Signals	yes
Zero-Crossing Detection	no

Tips

For buses at subsystem and model interfaces, you can use In Bus Element blocks instead of an Inport block with a Bus Selector block. In Bus Element blocks:

• Reduce line complexity and clutter in a block diagram.

• Make it easier to change the interface incrementally.

• Allow access to a bus element closer to the point of usage, avoiding the use of a Bus Selector and Goto block configuration.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using Simulink® Coder™.

Actual data type or capability support depends on block implementation.

HDL Code Generation

Generate Verilog and VHDL code for FPGA and ASIC designs using HDL Coder™.

HDL Coder™ provides additional configuration options that affect HDL implementation and synthesized logic.

To learn more about using buses for HDL code generation, see Buses (HDL Coder) and Use Bus Signals to Improve Readability of Model and Generate HDL Code (HDL Coder).

HDL Architecture

This block has one default HDL architecture.

HDL Block Properties

ConstrainedOutputPipeline	Number of registers to place at the outputs by moving existing delays within your design. Distributed pipelining does not redistribute these registers. The default is 0. For more details, see ConstrainedOutputPipeline (HDL Coder).
InputPipeline	Number of input pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see InputPipeline (HDL Coder).
OutputPipeline	Number of output pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see OutputPipeline (HDL Coder).

PLC Code Generation
Generate Structured Text code using Simulink® PLC Coder™.

Fixed-Point Conversion

Design and simulate fixed-point systems using Fixed-Point Designer™.

Actual data type or capability support depends on block implementation.

Version History

Introduced before R2006a