Select output signal based on control signal (2024)

Select output signal based on control signal

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Libraries:
Simulink / Signal Routing
HDL Coder / Signal Routing

Description

The Multiport Switch block determines which of several inputs to the blockpasses to the output. The block bases this decision on the value of the first input. Thefirst input is the control input and the remaining inputs are the data inputs. The valueof the control input determines which data input passes to the output.

The table summarizes how the block interprets the control inputand determines the data input that is passed to the output.

Control Input	Truncation	Setting for Data Port Order	Block Behavior During Simulation
Control Input	Truncation	Setting for Data Port Order	Indexing to Select Data Input	Out-of-Range Condition
Integer value	None	`Zero-based contiguous`	Zero-based indexing	The control input is less than `0` or greater than the number of data inputs minus one.
		`One-based contiguous`	One-based indexing	The control input is less than `1` or greater than the number of data inputs.
		`Specify indices`	Indices you specify	The control input does not correspond to any specified data port index.
Not an integer value	The block truncates the value to an integer by rounding to zero.	`Zero-based contiguous`	Zero-based indexing	The truncated control input is less than `0` or greater than the number of data inputs minus one.
		`One-based contiguous`	One-based indexing	The truncated control input is less than `1` or greater than the number of data inputs.
		`Specify indices`	Indices you specify	The truncated control input does not correspond to any specified data port index.

For information on how theblock handles the out-of-range condition, see How the Block Handles an Out-of-Range Control Input.

Multiport Switch Configured as an Index Vector Block

An Index Vector is a specialconfiguration of a Multiport Switch block in which you specify onedata input and the control input is zero-based. The block output is the element ofthe input vector whose index matches the control input. For example, if the inputvector is [18 15 17 10] and the control input is3, the element that matches the index of 3 (zero-based) is10, and that becomes the output value.

To configure a Multiport Switch block to work as an IndexVector block, set Number of data ports to1 and Data port order toZero-based contiguous.

How the Block Handles an Out-of-Range Control Input

For an input with an integer value less than intmax(‘int32’), the inputis out of range when the value does not match any data port indices. For a controlinput that is not an integer value, the input is out of range when thetruncated value does not match any data port indices. Inboth cases, the block behavior depends on your settings for Data port fordefault case and Diagnostic for defaultcase.

Note

If the control input is larger than intmax(‘int32’), theblock wraps the input value to an integer.

Behavior for Simulation

The following behavior applies only to simulation for your model.

Data Port for Default Case	Diagnostic for Default Case
Data Port for Default Case	None	Warning	Error
`Last data port`	Use the last data port and do not report any warning or error.	Use the last data port and report a warning.	Report an error and stop simulation.
`Additional data port`	Use the additional data port with a `*` label and do not report any warning or error.	Use the additional data port with a `*` label and report a warning.	Report an error and stop simulation.

Behavior for Code Generation

The following behavior applies to code generation for your model.

Data Port for Default Case	Diagnostic for Default Case
Data Port for Default Case	None	Warning	Error
`Last data port`	Use the last data port.	Use the last data port.	Use the last data port.
`Additional data port`	Use the additional data port with a `*` label.	Use the additional data port with a `*` label.	Use the additional data port with a `*` label.

Use Data Inputs That Have Different Dimensions

If two signals have a different number of dimensions or differentdimension lengths, you can use the signals as data inputs to a Multiport Switch block. In the block dialog box, select the parameter Allow different data input sizes. In this case, the output of the block is a variable-size signal. If you do not select this parameter, the block generates an error.

For more information about the parameter, see Allow different data input sizes (Results in variable-size output signal). Formore information about variable-size signals, see Variable-Size Signal Basics.

Rules That Determine the Block Behavior

You specify the number of data inputs with Number of data ports.

If you set Number of data ports to1, the block behaves as an index selector or index vector and not as a multiport switch. For more details,see Multiport Switch Configured as an Index Vector Block.
If you set Number of data ports to an integer greater than 1, the block behaves as a multiport switch. The block output is the data input that corresponds to the value of the control input. If at least one of the data inputs is a vector, the block output is a vector. In this case, the block expands any scalar inputs to vectors.
If all the data inputs are scalar, the output is a scalar.

Guidelines on Setting Parameters for Enumerated Control Port

When the control port on the Multiport Switch block is of enumerated type, follow these guidelines:

Scenario	What to Do	Rationale
The enumerated type contains a value that represents invalid, out-of-range, or uninitialized values.	Set Data port order to `Specify indices`. Set Data port indices to use this value for the last data port. Set Data port for default case to `Last data port`.	This block configuration handles invalid values that the enumerated type explicitly represents.
The enumerated type contains only valid enumerated values. However, a data input port can get invalid values of enumerated type.	Set Data port for default case to `Additional data port`.	This block configuration handles invalid values that the enumerated type does not explicitly represent.
The enumerated type contains only valid enumerated values. Data input ports can never get invalid values of enumerated type.	Set Data port for default case to `Last data port`. Set Diagnostic for default case to `None`.	This block configuration avoids unnecessary diagnostic action.
The block does not have a data input port for every value of the enumerated type.	Set Data port for default case to `Additional data port`.	This block configuration handles enumerated values that do not have a data input port, along with invalid values.

Examples

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Noncontiguous Values for Data Port Indices of Multiport Switch Block

Open Model

This example shows how to use a Multiport Switch block that specifies noncontiguous integer values for data ports. The values of the indices are visible on the data port labels. You do not have to open the block dialog box to determine which value maps to each data port.

When you set Data port for default case to Additional data port, an extra port with a * label appears. This port corresponds to the default case, which applies when the control input does not match the data port indices 3, 5, 0, or 18. When that happens in this example, the Multiport Switch block outputs a value of 1.

Zero-Based Indexing for Multiport Switch Data Ports

Open Model

This example shows a Multiport Switch block that uses zero-based indexing for contiguous ordering of three data ports.

The indices are visible on the data port labels. You do not have to open the block dialog box to determine if the data ports use zero-based or one-based indexing.

When you set Data port for default case to Last data port, the last data port includes a * on the label (in this case, the label is *,2). The comma after the * indicates that the data port index has a value. This port corresponds to the default case, which applies when the control input does not match the data port indices. In this example, the Multiport Switch block outputs a value of -0.1 when the control input does not match the data port indices of 0, 1, or 2.

One-Based Indexing for Multiport Switch Data Ports

Open Model

The sf_semantics_hotel_checkin model uses a Multiport Switch block. This block uses one-based indexing for contiguous ordering of three data ports.

When you increase the size of the block icon, the indices are visible on the data port labels. You do not have to open the block dialog box to determine whether the data ports use zero-based or one-based indexing.

Enumerated Names for Data Port Indices of the Multiport Switch Block

Open Model

The sldemo_fuelsys model uses a Multiport Switch block in the fuel_rate_control/fuel_calc/feedforward_fuel_rate subsystem. This block uses the enumerated type sld_FuelModes to specify three data port indices: LOW, RICH, and DISABLED.

When you set Data port for default case to Last data port, the last data port includes a * on the label. The comma and ellipsis after the * indicate that the data port index has a value. This port corresponds to the default case, which applies when the control input does not match the data port indices LOW, RICH, or DISABLED. In this case, the Multiport Switch block outputs a value of 0.

Extended Examples

Model Fault-Tolerant Fuel Control SystemCombine Stateflow® with Simulink® to model hybrid systems. This type of modeling is particularly useful for systems that have numerous possible operational modes based on discrete events. Traditional signal flow is handled in Simulink while changes in control configuration are implemented in Stateflow. The model described in this example represents a fuel control system for a gasoline engine. The system is robust in that individual sensor failures are detected and the control system is dynamically reconfigured for uninterrupted operation.

Open Model

Limitations

If the data inputs to the Multiport Switch block are buses, theelement names of both buses must be the same. Using the same element namesensures that the output bus has the same element names no matter which input busthe block selects. To ensure that your model meets this requirement, use a busobject to define the buses and set the Element name mismatchdiagnostic to error.
For arrays of buses, Number of data ports must be set toa value of 2 or greater.

Ports

Input

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Port_1 — Control signal
scalar

The control signal can be of any data type that Simulink^® supports, including fixed-point and enumerated types. Whenthe control input is not an integer value, the block truncates the valueto an integer by rounding to zero.

Limitations

If the control signal is numeric, the control signalcannot be complex.
If the control signal is an enumerated signal, the blockuses the value of the underlying integer to select a dataport.
If the underlying integer does not correspond to a dataport, an error occurs.
If the control input is a floating point value thatexceeds the datatype range of integers, the MultiportSwitch block issues a runtime error. This rangeincludes Inf andNaN.

1 — First data input
scalar | vector | matrix | N-D array

First data input, specified as a scalar, vector, matrix, or N-D array.All input data signals can be of any data type that Simulink supports.

If all the data inputs are scalar, the output is scalar
If at least one of the data inputs is a vector, the blockoutput is a vector. In this case, the block expands any scalarinputs to vectors.
If any two nonscalar signals have a different number ofdimensions or different dimension lengths, select theAllow different data input sizes checkbox. For more information, see Use Data Inputs That Have Different Dimensions
If any data signal is of an enumerated type, all others mustbe of the same enumerated type.

2 — Second data input
scalar | vector | matrix | N-D array

Second data input, specified as a scalar, vector, matrix, or N-Darray. All input data signals can be of any data type that Simulink supports.

If all the data inputs are scalar, the output is scalar
If at least one of the data inputs is a vector, the blockoutput is a vector. In this case, the block expands any scalarinputs to vectors.
If any two nonscalar signals have a different number ofdimensions or different dimension lengths, select theAllow different data input sizes checkbox. For more information, see Use Data Inputs That Have Different Dimensions
If any data signal is of an enumerated type, all others mustbe of the same enumerated type.

Dependencies

To enable this port, set Number of data portsto an integer greater than 1.

N — Nth data input
scalar | vector | matrix | N-D array

Nth data input, specified as a scalar, vector, matrix, or N-D array.All input data signals can be of any data type that Simulink supports.

If all the data inputs are scalar, the output is scalar
If at least one of the data inputs is a vector, the blockoutput is a vector. In this case, the block expands any scalarinputs to vectors.
If any two nonscalar signals have a different number ofdimensions or different dimension lengths, select theAllow different data input sizes checkbox. For more information, see Use Data Inputs That Have Different Dimensions
If any data signal is of an enumerated type, all others mustbe of the same enumerated type.

Dependencies

To enable the Nth input port, set Number of dataports to an integer value greater than or equal toN.

* — Data port for out-of-range inputs
scalar | vector | matrix | N-D array

Input data port for out-of-range control signal inputs, specified as ascalar, vector, matrix, or N-D array. All input data signals can be ofany data type that Simulink supports. If any data signal is of an enumerated type, allothers must be of the same enumerated type. If any two signals have adifferent number of dimensions or different dimension lengths, selectthe Allow different data input sizes check box. Formore information, see Use Data Inputs That Have Different Dimensions.

Dependencies

To create an additional data port for out-of-range control signalinputs, set Data port for default case toAdditional data port. When you setData port for default case toLast data port, the block uses thelast data port for output when the control signal value does notmatch any data port indices.

Output

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Port_1 — Selected data input, based on control signal value
scalar | vector | matrix | N-D array

The block outputs one of the data inputs, selected according to the control signalvalue. The output has the same dimensions as the corresponding datainput. The output data type is the data type of the input port thatrequires the largest memory space. When you select the Allowdifferent data input sizes check box, the output of theblock is a variable size signal.

Parameters

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Main

Data port order — Type of ordering for data input ports
`One-based contiguous` | `Zero-based contiguous` | `Specify indices`

Specify the type of ordering for your data input ports.

Zero-based contiguous — Block useszero-based indexing for ordering contiguous data ports. This isthe default value of the Index Vectorblock.
One-based contiguous — Block usesone-based indexing for ordering contiguous data ports. This isthe default value of the Multiport Switchblock
Specify indices — Block usesnoncontiguous indexing for ordering data ports.

Tips

When the control port is of enumerated type, selectSpecify indices.
If you select Zero-basedcontiguous or One-basedcontiguous, verify that the control portis not of enumerated type. This configuration is deprecatedand produces an error. You can run the Upgrade Advisor onyour model to replace each Multiport Switchblock of this configuration with a block that explicitlyspecifies data port indices. See Model Upgrades.
Avoid situations where the block contains unused dataports for simulation or code generation. When the controlport is of fixed-point or built-in data type, verify thatall data port indices are representable with that type.Otherwise, the following block behavior occurs.
If the Block Has Unused DataPorts and Data Port Order Is: The Block Produces:
Zero-based contiguousor One-based contiguous Awarning
Specify indices Anerror

If the Block Has Unused DataPorts and Data Port Order Is:	The Block Produces:
`Zero-based contiguous`or `One-based contiguous`	Awarning
`Specify indices`	Anerror

Dependencies

Selecting Zero-based contiguous orOne-based contiguous enables theNumber of data ports parameter.

Selecting Specify indices enables theData port indices parameter.

Programmatic Use

Block Parameter:DataPortOrder

Type: character vector

Values:'Zero-based contiguous' | 'One-based contiguous' |'Specify indices'

Default:'One-based contiguous' (MultiportSwitch) 'Zero-based contiguous'(Index Vector)

Number of data ports — Number of data input ports
`1` | `3` | integer between 1 and 65535

Specify the number of data input ports to the block. The total number of input ports isthe number you specify, plus one for the control signal input port, andplus one more if you set Data port for default caseto Additional data port.

Dependencies

To enable this parameter, set Data port orderto Zero-based contiguous orOne-based contiguous.

Programmatic Use

Block Parameter:Inputs

Type: character vector

Values: integer between 1 and65536

Default:'3' (Multiport Switch)'1' (IndexVector)

Data port indices — Array of indices for data ports
`{1,2,3}` (default) | array of indices

Specify an array of indices for your data ports. The block iconchanges to match the data port indices you specify.

Tips

To specify an array of indices that correspond to allvalues of an enumerated type, enterenumeration('name of thetype').
For example, enumeration('MyColors') isa valid entry if MyColors is the name ofan enumerated type.
To enter specific values of an enumerated type, use thetype_name.enumerated_nameformat. Do not enter the underlying integer value.
For example, enumeration({MyColors.Red, MyColors.Green,MyColors.Blue}) is a valid entry.
To indicate that more than one value maps to a data port,use brackets.
For example, the following entries are both valid:
- enumeration({MyColors.Red,MyColors.Green, [MyColors.Blue,MyColors.Yellow]})
- enumeration({[3,5],0,18})
If the control port is of fixed-point or built-in datatype, the values for Data port indicesmust be representable with that type. Otherwise, an errorappears at compile time to alert you to unused dataports.
If the control port is of enumerated data type, the valuesfor Data port indices must beenumerated values of that type.
If Data port indices contains valuesof enumerated type, the control port must be of that datatype.

Dependencies

To enable this parameter, set Data port orderto Specify indices.

Programmatic Use

Block Parameter:DataPortIndices

Type: character vector

Values: array ofindices

Default:'{1,2,3}'

Data port for default case — Port to use for out-of-range inputs
`Last data port` (default) | `Additional data port`

Specify whether to use the last data port for out-of-range inputs, or to use anadditional port. An asterisk (*) next to the port name indicates theport the block uses when the control port value does not match any dataport indices.

Last data port — Block uses thelast data port for output when the control port value does notmatch any data port indices.
Additional data port — Block usesan additional data port for output when the control port valuedoes not match any data port indices.

Tip

If you set this parameter to Additional dataport and Number of data portsis 3, the number of input ports on theblock is 5. The first input is the control port, the next threeinputs are data ports, and the fifth input is the default port forout-of-range inputs.

Programmatic Use

Block Parameter:DataPortForDefault

Type: character vector

Values:'Last data port' | 'Additional dataport'

Default:'Last data port'

Diagnostic for default case — Diagnostic action when control port value does not match data port indices
`Error` (default) | `Warning` | `None`

Specify the diagnostic action to take when the control port value does not match anydata port indices.

None — Produce no response.
Warning — Display a warning andcontinue the simulation.
Error — Terminate the simulationand display an error. In this case, the Data port fordefault case is used only for code generation andnot simulation.

For more information, see How the Block Handles an Out-of-Range Control Input.

Programmatic Use

Block Parameter:DiagnosticForDefault

Type: charactervector

Values:'None' | 'Warning' | 'Error'

Default:'Error'

Sample time (-1 for inherited) — Interval between samples
`-1` (default) | scalar | vector

Specify the time interval between samples. To inherit the sample time, set this parameter to -1. For more information, see Specify Sample Time.

Dependencies

This parameter is visible only if you set it to a value other than -1. To learn more, see Blocks for Which Sample Time Is Not Recommended.

Programmatic Use

Block Parameter: SampleTime

Type: string scalar or character vector

Default: "-1"

Signal Attributes

Require all data port inputs to have the same data type — Require all inputs to have the same data type
`off` (default) | `on`

Select this check box to require that all data input ports have the same data type. When you clear this check box, the block allows data port inputs to have different data types.

Programmatic Use

Block Parameter: InputSameDT

Type: character vector

Values: 'off' | 'on'

Default: 'off'

Output minimum — Minimum output value for range checking
`[]` (default) | scalar

Lower value of the output range that Simulink checks.

Simulink uses the minimum to perform:

Parameter range checking (see Specify Minimum and Maximum Values for Block Parameters) for some blocks.
Simulation range checking (see Specify Signal Ranges and Enable Simulation Range Checking).
Automatic scaling of fixed-point data types.
Optimization of the code that you generate from the model. This optimization can remove algorithmic code and affect the results of some simulation modes such as SIL or external mode. For more information, see Optimize using the specified minimum and maximum values (Embedded Coder).

Note

Output minimum does not saturate or clip the actual output signal. Use the Saturation block instead.

Programmatic Use

Block Parameter: OutMin

Type: character vector

Values: '[ ]'| scalar

Default: '[ ]'

Output maximum — Maximum output value for range checking
`[]` (default) | scalar

Upper value of the output range that Simulink checks.

Simulink uses the maximum value to perform:

Parameter range checking (see Specify Minimum and Maximum Values for Block Parameters) for some blocks.
Simulation range checking (see Specify Signal Ranges and Enable Simulation Range Checking).
Automatic scaling of fixed-point data types.
Optimization of the code that you generate from the model. This optimization can remove algorithmic code and affect the results of some simulation modes such as SIL or external mode. For more information, see Optimize using the specified minimum and maximum values (Embedded Coder).

Note

Output maximum does not saturate or clip the actual output signal. Use the Saturation block instead.

Programmatic Use

Block Parameter: OutMax

Type: character vector

Values: '[ ]'| scalar

Default: '[ ]'

Output data type — Specify the output data type
`Inherit: Inherit via internal rule` (default) | `Inherit: Inherit via back propagation` | `Inherit: Same as first data input` | `double` | `single` | `half` | `int8` | `uint8` | `int16` | `uint16` | `int32` | `uint32` | `int64` | `uint64` | `fixdt(1,16)` | `fixdt(1,16,0)` | `fixdt(1,16,2^0,0)` | `string` | `Simulink.ImageType(480,640,3)` | `<data type expression>`

Choose the data type for the output. The type can be inherited, specified directly, or expressed as a data type object such as Simulink.NumericType.

When you select an inherited option, the block behaves as follows:

Inherit: Inherit via internal rule—Simulink chooses a data type to balance numerical accuracy, performance, and generated code size, while taking into account the properties of the embedded target hardware. If you change the embedded target settings, the data type selected by the internal rule might change. It is not always possible for the software to optimize code efficiency and numerical accuracy at the same time. If the internal rule doesn’t meet your specific needs for numerical accuracy or performance, use one of the following options:
- Specify the output data type explicitly.
- Explicitly specify a default data type such as fixdt(1,32,16) and then use the Fixed-Point Tool to propose data types for your model. For more information, see fxptdlg (Fixed-Point Designer).
- To specify your own inheritance rule, use Inherit: Inherit via back propagation and then use a Data Type Propagation block. Examples of how to use this block are available in the Signal Attributes library Data Type Propagation Examples block.
Inherit: Inherit via back propagation — Uses the data type of the driving block.
Inherit: Same as first data input — Uses the data type of the first data input port.

Programmatic Use

Block Parameter: OutDataTypeStr

Type: character vector

Default: 'Inherit: Inherit via internal rule'

Lock output data type setting against changes by the fixed-point tools — Prevent fixed-point tools from overriding data types
`off` (default) | `on`

Select to lock the output data type setting of this block against changes by the Fixed-Point Tool and the Fixed-Point Advisor. For more information, see Use Lock Output Data Type Setting (Fixed-Point Designer).

Programmatic Use

Block Parameter: LockScale

Type: character vector

Values: 'off' | 'on'

Default: 'off'

Integer rounding mode — Specify the rounding mode for fixed-point operations
`Floor` (default) | `Ceiling` | `Convergent` | `Nearest` | `Round` | `Simplest` | `Zero`

Choose one of these rounding modes.

Ceiling: Rounds both positive and negative numbers toward positive infinity. Equivalent to the MATLAB^® ceil function.
Convergent: Rounds number to the nearest representable value. If a tie occurs, rounds to the nearest even integer. Equivalent to the Fixed-Point Designer™ convergent function.
Floor: Rounds both positive and negative numbers toward negative infinity. Equivalent to the MATLAB floor function.
Nearest: Rounds number to the nearest representable value. If a tie occurs, rounds toward positive infinity. Equivalent to the Fixed-Point Designer nearest function.
Round: Rounds number to the nearest representable value. If a tie occurs, rounds positive numbers toward positive infinity and rounds negative numbers toward negative infinity. Equivalent to the Fixed-Point Designer round function.
Simplest: Automatically chooses between round toward floor and round toward zero to generate rounding code that is as efficient as possible.
Zero: Rounds number toward zero. Equivalent to the MATLAB fix function.

Programmatic Use

Block Parameter: RndMeth

Type: character vector

Default: 'Floor'

Saturate on integer overflow — Method of overflow action
`off` (default) | `on`

Specify whether overflows saturate or wrap.

off — Overflows wrap to the appropriate value that the data type can represent.
For example, the number 130 does not fit in a signed 8-bit integer and wraps to -126.
on — Overflows saturate to either the minimum or maximum value that the data type can represent.
For example, an overflow associated with a signed 8-bit integer can saturate to -128 or 127.

Tip

Consider selecting this check box when your model has a possible overflow and you want explicit saturation protection in the generated code.
Consider clearing this check box when you want to optimize efficiency of your generated code.
Clearing this check box also helps you to avoid overspecifying how a block handles out-of-range signals. For more information, see Troubleshoot Signal Range Errors.
When you select this check box, saturation applies to every internal operation on the block, not just the output or result.
In general, the code generation process can detect when overflow is not possible. In this case, the code generator does not produce saturation code.

Programmatic Use

Block Parameter: SaturateOnIntegerOverflow

Type: character vector

Values: 'off' | 'on'

Default: 'off'

Allow different data input sizes (Results in variable-size output signal) — Allow input signals with different sizes
`off` (default) | `on`

Select this check box to allow input signals with different sizes.

On — Allows input signals with different sizes, and propagate the input signal size to the output signal. In this mode, the block produces a variable-size output signal.
Off — Requires that all nonscalar data input signals be the same size.

Programmatic Use

Parameter: AllowDiffInputSizes

Type: character vector

Value: 'on' | 'off'

Default: 'off'

Mode — Select data type mode
`Inherit` (default) | `Built in` | `Fixed Point`

Select the category of data to specify.

Inherit — Inheritance rules for data types. Selecting Inherit enables a second menu/text box to the right where you can select the inheritance mode.
Built in — Built-in data types. Selecting Built in enables a second menu/text box to the right where you can select a built-in data type.
Fixed point — Fixed-point data types. Selecting Fixed point enables additional parameters that you can use to specify a fixed-point data type.
Expression — Expressions that evaluate to data types. Selecting Expression enables a second menu/text box to the right, where you can enter the expression.

For more information, see Specify Data Types Using Data Type Assistant.

Dependencies

To enable this parameter, click the Show data type assistant button.

Data type override — Specify data type override mode for this signal
`Inherit` | `Off`

Select the data type override mode for this signal.

When you select Inherit, Simulink inherits the data type override setting from its context, that is, from the block, Simulink.Signal object or Stateflow^® chart in Simulink that is using the signal.
When you select Off, Simulink ignores the data type override setting of its context and uses the fixed-point data type specified for the signal.

For more information, see Specify Data Types Using Data Type Assistant in the Simulink documentation.

Dependencies

To enable this parameter, set Mode to Built in or Fixed point.

Tips

The ability to turn off data type override for an individual data type provides greater control over the data types in your model when you apply data type override. For example, you can use this option to ensure that data types meet the requirements of downstream blocks regardless of the data type override setting.

Signedness — Specify signed or unsigned
`Signed` (default) | `Unsigned`

Specify whether the fixed-point data is signed or unsigned. Signed data can represent positive and negative values, but unsigned data represents positive values only.

Signed, specifies the fixed-point data as signed.
Unsigned, specifies the fixed-point data as unsigned.

For more information, see Specify Data Types Using Data Type Assistant.

Dependencies

To enable this parameter, set the Mode to Fixed point.

Scaling — Method for scaling fixed-point data
`Best precision` (default) | `Binary point` | `Slope and bias`

Specify the method for scaling your fixed-point data to avoid overflow conditions and minimize quantization errors. For more information, see Specifying a Fixed-Point Data Type.

Dependencies

To enable this parameter, set Mode to Fixed point.

Word length — Bit size of the word that holds the quantized integer
`16` (default) | integer from 0 to 32

Specify the bit size of the word that holds the quantized integer. For more information, see Specifying a Fixed-Point Data Type.

Dependencies

To enable this parameter, set Mode to Fixed point.

Fraction length — Specify fraction length for fixed-point data type
`0` (default) | scalar integer

Specify fraction length for fixed-point data type as a positive or negative integer. For more information, see Specifying a Fixed-Point Data Type.

Dependencies

To enable this parameter, set Scaling to Binary point.

Slope — Specify slope for the fixed-point data type
`2^0` (default) | positive, real-valued scalar

Specify slope for the fixed-point data type. For more information, see Specifying a Fixed-Point Data Type.

Dependencies

To enable this parameter, set Scaling to Slope and bias.

Bias — Specify bias for the fixed-point data type
`0` (default) | real-valued scalar

Specify bias for the fixed-point data type as any real number. For more information, see Specifying a Fixed-Point Data Type.

Dependencies

To enable this parameter, set Scaling to Slope and bias.

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`

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

HDL Code Generation
Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.

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

HDL Architecture

This block has one default HDL architecture.

HDL Block Properties

General
CodingStyle	Specify whether to generate HDL code with case statements or if-else statements. Bydefault, HDL Coder generates if-else statements. See also CodingStyle (HDL Coder).
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).

Native Floating Point
LatencyStrategy	Specify whether to map the blocks in your design to `inherit`, `Max`, `Min`, or `Zero` for the floating-point operator. The default is `inherit`. See also LatencyStrategy (HDL Coder).

Complex Data Support

This block supports code generation for complex signals.

Setting Data Port Indices Using Specify Indices mode

You can specify the data port indices to the input port using specify indicesmode. To configure the Multiport Switch block with specify indices mode, set theData port order block parameter to Specifyindices. Then, enter the port indices in the Dataport indices block parameter. For a model targeted for HDL codegeneration, you can use these input data types for the control input in aspecify indices mode:

Fixed-point and floating-point types
Signed and unsigned integer types
Enumerated types
Vector, matrix, and bus types

Using an Enumerated Type as Port Index

You can set Data port order to Specifyindices, and enter enumeration values for the Dataport indices. For example, you can connect the EnumeratedConstant block to the Multiport Switch controlport and use the enumerated types as data port indices.

Restrictions

You must avoid using of NaN or out of range values at thecontrol port. It can cause simulation mismatch in the validation model.

PLC Code Generation
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Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.

Version History

Introduced before R2006a

expand all

R2024a: Multiport Switch block has runtime error when input has floatingpoint value

The Multiport Switch block now issues a runtime error when thecontrol signal in the first port has a floating point value that exceeds thedatatype range of integers. This range includes Inf andNaN.

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Select output signal based on control signal (2024)

Description

Multiport Switch Configured as an Index Vector Block

How the Block Handles an Out-of-Range Control Input

Use Data Inputs That Have Different Dimensions

Rules That Determine the Block Behavior

Guidelines on Setting Parameters for Enumerated Control Port

Examples

Noncontiguous Values for Data Port Indices of Multiport Switch Block

Zero-Based Indexing for Multiport Switch Data Ports

One-Based Indexing for Multiport Switch Data Ports

Enumerated Names for Data Port Indices of the Multiport Switch Block

Extended Examples

Limitations

Ports

Input

Port_1 — Control signalscalar

Limitations

1 — First data input scalar | vector | matrix | N-D array

2 — Second data input scalar | vector | matrix | N-D array

Dependencies

N — Nth data input scalar | vector | matrix | N-D array

Dependencies

* — Data port for out-of-range inputs scalar | vector | matrix | N-D array

Dependencies

Output

Port_1 — Selected data input, based on control signal valuescalar | vector | matrix | N-D array

Parameters

Main

Data port order — Type of ordering for data input portsOne-based contiguous | Zero-based contiguous | Specify indices

Tips

Dependencies

Programmatic Use

Number of data ports — Number of data input ports 1 | 3 | integer between 1 and 65535

Dependencies

Programmatic Use

Data port indices — Array of indices for data ports {1,2,3} (default) | array of indices

Tips

Dependencies

Programmatic Use

Data port for default case — Port to use for out-of-range inputs Last data port (default) | Additional data port

Tip

Programmatic Use

Diagnostic for default case — Diagnostic action when control port value does not match data port indicesError (default) | Warning | None

Programmatic Use

Sample time (-1 for inherited) — Interval between samples -1 (default) | scalar | vector

Dependencies

Programmatic Use

Signal Attributes

Require all data port inputs to have the same data type — Require all inputs to have the same data typeoff (default) | on

Programmatic Use

Output minimum — Minimum output value for range checking[] (default) | scalar

Programmatic Use

Output maximum — Maximum output value for range checking [] (default) | scalar

Programmatic Use

Programmatic Use

Lock output data type setting against changes by the fixed-point tools — Prevent fixed-point tools from overriding data types off (default) | on

Programmatic Use

Integer rounding mode — Specify the rounding mode for fixed-point operations Floor (default) | Ceiling | Convergent | Nearest | Round | Simplest | Zero

Programmatic Use

See Also

Saturate on integer overflow — Method of overflow action off (default) | on

Programmatic Use

Allow different data input sizes (Results in variable-size output signal) — Allow input signals with different sizesoff (default) | on

Programmatic Use

Mode — Select data type mode Inherit (default) | Built in | Fixed Point

Dependencies

Data type override — Specify data type override mode for this signal Inherit | Off

Dependencies

Tips

Signedness — Specify signed or unsigned Signed (default) | Unsigned

Dependencies

Scaling — Method for scaling fixed-point data Best precision (default) | Binary point | Slope and bias

Dependencies

Word length — Bit size of the word that holds the quantized integer 16 (default) | integer from 0 to 32

Dependencies

Fraction length — Specify fraction length for fixed-point data type 0 (default) | scalar integer

Dependencies

Slope — Specify slope for the fixed-point data type 2^0 (default) | positive, real-valued scalar

Dependencies

Port_1 — Control signal
scalar

1 — First data input
scalar | vector | matrix | N-D array

2 — Second data input
scalar | vector | matrix | N-D array

N — Nth data input
scalar | vector | matrix | N-D array

* — Data port for out-of-range inputs
scalar | vector | matrix | N-D array

Port_1 — Selected data input, based on control signal value
scalar | vector | matrix | N-D array

Data port order — Type of ordering for data input ports
`One-based contiguous` | `Zero-based contiguous` | `Specify indices`

Number of data ports — Number of data input ports
`1` | `3` | integer between 1 and 65535

Data port indices — Array of indices for data ports
`{1,2,3}` (default) | array of indices

Data port for default case — Port to use for out-of-range inputs
`Last data port` (default) | `Additional data port`

Diagnostic for default case — Diagnostic action when control port value does not match data port indices
`Error` (default) | `Warning` | `None`

Sample time (-1 for inherited) — Interval between samples
`-1` (default) | scalar | vector

Require all data port inputs to have the same data type — Require all inputs to have the same data type
`off` (default) | `on`

Output minimum — Minimum output value for range checking
`[]` (default) | scalar

Output maximum — Maximum output value for range checking
`[]` (default) | scalar

Lock output data type setting against changes by the fixed-point tools — Prevent fixed-point tools from overriding data types
`off` (default) | `on`

Integer rounding mode — Specify the rounding mode for fixed-point operations
`Floor` (default) | `Ceiling` | `Convergent` | `Nearest` | `Round` | `Simplest` | `Zero`

Saturate on integer overflow — Method of overflow action
`off` (default) | `on`

Allow different data input sizes (Results in variable-size output signal) — Allow input signals with different sizes
`off` (default) | `on`

Mode — Select data type mode
`Inherit` (default) | `Built in` | `Fixed Point`

Data type override — Specify data type override mode for this signal
`Inherit` | `Off`

Signedness — Specify signed or unsigned
`Signed` (default) | `Unsigned`

Scaling — Method for scaling fixed-point data
`Best precision` (default) | `Binary point` | `Slope and bias`

Word length — Bit size of the word that holds the quantized integer
`16` (default) | integer from 0 to 32

Fraction length — Specify fraction length for fixed-point data type
`0` (default) | scalar integer

Slope — Specify slope for the fixed-point data type
`2^0` (default) | positive, real-valued scalar

Bias — Specify bias for the fixed-point data type
`0` (default) | real-valued scalar

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

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