Truth Table

Represent logical decision-making behavior with conditions, decisions, and actions

Library:
Stateflow

Description

The Truth Table block is a truth table function that uses MATLAB^® as the action language. When you want to use truth table logic directly in a Simulink^® model, use this block. This block requires Stateflow^®.

When you add a Truth Table block directly to a model instead of calling truth table functions from a Stateflow chart, these advantages apply:

It is a more direct approach than creating a truth table within a Stateflow chart, especially if your model requires only a single truth table.
You can define truth table inputs and outputs with inherited types and sizes.

The Truth Table block works with a subset of the MATLAB language that is optimized for generating embeddable C code. This block generates content as MATLAB code. As a result, you can take advantage of other tools to debug your Truth Table block during simulation.

If you double-click the Truth Table block, the Truth Table Editor opens to display its conditions, actions, and decisions.

Using the Truth Table Editor, you can:

Enter and edit conditions, actions, and decisions.
Add or modify Stateflow data and ports by using the Ports and Data Manager.
Run diagnostics to detect parser errors.
View generated content after simulation.

For more information about the Truth Table Editor, see Use Truth Tables to Model Combinatorial Logic.

Ports

Input

expand all

`u` — Input port
scalar | vector | matrix

When you create input data in the Symbols pane, Stateflow creates input ports. The input data that you create has a corresponding input port that appears once you create data.

Output

expand all

`y` — Output port
scalar | vector | matrix

When you create output data in the Symbols pane, Stateflow creates output ports. The output data that you create has a corresponding output port that appears once you create data.

Parameters

expand all

Parameters on the Code Generation tab require Simulink Coder™ or Embedded Coder^®.

Main

`Show port labels` — Select how to display port labels
`FromPortIcon` (default) | `FromPortBlockName` | `SignalName`

Select how to display port labels on the Chart block icon.

none: Do not display port labels.
FromPortIcon: If the corresponding port icon displays a signal name, display the signal name on the Chart block. Otherwise, display the port block name.
FromPortBlockName: Display the name of the corresponding port block on the Chart block.
SignalName: If a signal name exists, display the name of the signal connected to the port on the Chart block. Otherwise, display the name of the corresponding port block.

Programmatic Use

Parameter: ShowPortLabels

Type: character vector

Value: 'FromPortIcon' | 'FromPortBlockName' | 'SignalName'

Default: 'FromPortIcon'

`Read/Write permissions` — Select access to contents of chart
`ReadWrite` (default) | `ReadOnly` | `NoReadOrWrite`

Control user access to the contents of the chart.

ReadWrite: Enable opening and modification of chart contents.
ReadOnly: Enable opening but not modification of the chart. If the chart resides in a block library, you can create and open links to the chart and can make and modify local copies of the chart but you cannot change the permissions or modify the contents of the original library instance.
NoReadOrWrite: Disable opening or modification of chart. If the chart resides in a library, you can create links to the chart in a model but you cannot open, modify, change permissions, or create local copies of the chart.

Programmatic Use

Parameter: Permissions

Type: character vector

Value: 'ReadWrite' | 'ReadOnly' | 'NoReadOrWrite'

Default: 'ReadWrite'

`Treat as atomic unit` — Control execution of a subsystem as one unit
off (default) | on

When determining the execution order of block methods, causes Simulink to treat the chart as a unit.

off: When determining block method execution order, treat all blocks in the chart as being at the same level in the model hierarchy as the chart. This hierarchy treatment can cause the execution of methods of blocks in the chart to be interleaved with the execution of methods of blocks outside the chart.
on: When determining the execution order of block methods, treat the chart as a unit. For example, when Simulink needs to compute the output of the chart, Simulink invokes the output methods of all the blocks in the chart before invoking the output methods of other blocks at the same level as the chart block.

Dependency

If you select this parameter, you enable the Minimize algebraic loop occurrences, Sample time, and Function packaging parameters. Function packaging requires the Simulink Coder software.

Programmatic Use

Parameter: TreatAsAtomicUnit

Type: character vector

Value: 'off' | 'on'

Default: 'off'

`Minimize algebraic loop occurrences` — Control elimination of algebraic loops
off (default) | on

off: Do not try to eliminate any artificial algebraic loops that include the atomic subchart.
on: Try to eliminate any artificial algebraic loops that include the atomic subchart.

Dependency

To enable this parameter, select the Treat as atomic unit parameter.

Programmatic Use

Parameter: MinAlgLoopOccurrences

Type: character vector

Value: 'off' | 'on'

Default: 'off'

`Sample time` — Specify time interval
`-1` (default) | `[Ts 0]`

Specify whether all blocks in this chart must run at the same rate or can run at different rates.

If the blocks in the chart can run at different rates, specify the chart sample time as inherited (-1).
If all blocks must run at the same rate, specify the sample time corresponding to this rate as the value of the Sample time parameter.
If any of the blocks in the chart specify a different sample time (other than -1 or inf), Simulink displays an error message when you update or simulate the model. For example, suppose all the blocks in the chart must run 5 times a second. To ensure this time, specify the sample time of the chart as 0.2. In this example, if any of the blocks in the chart specify a sample time other than 0.2, -1, or inf, Simulink displays an error when you update or simulate the model.

-1: Specify inherited sample time. If the blocks in the chart can run at different rates, use this sample time.
[Ts 0]: Specify periodic sample time.

Dependency

To enable this parameter, select the Treat as atomic unit parameter.

Programmatic Use

Parameter: SystemSampleTime

Type: character vector

Value: '-1' | '[Ts 0]'

Default: '-1'

`Treat as grouped when propagating variant conditions` — Control treating subsystem as unit
`on` (default) | `off`

When propagating variant conditions from Variant Source blocks or to Variant Sink blocks, causes Simulink to treat the chart as a unit.

on: Simulink treats the chart as a unit when propagating variant conditions from Variant Source blocks or to Variant Sink blocks. For example, when Simulink computes the variant condition of the chart, it propagates that condition to all the blocks in the chart.
off: Simulink treats all blocks in the chart as being at the same level in the model hierarchy as the chart itself when determining their variant condition.

Programmatic Use

Parameter: TreatAsGroupedWhenPropagatingVariantConditions

Type: character vector

Value: 'on' | 'off'

Default: 'on'

Code Generation

`Function packaging` — Select code format
`Auto` (default) | `Inline` | `Nonreusable function` | `Reusable function`

Select the generated code format for an atomic (nonvirtual) subchart.

Auto

Simulink Coder chooses the optimal format for your system based on the type and number of instances of the chart that exist in the model.

Inline

Simulink Coder inlines the chart unconditionally.

Nonreusable function

Simulink Coder explicitly generates a separate function in a separate file. Charts with this setting generate functions that might have arguments depending on the Function interface parameter setting. You can name the generated function and file using parameters Function name and File name (no extension). These functions are not reentrant.

Reusable function

Simulink Coder generates a function with arguments that allows reuse of chart code when a model includes multiple instances of the chart.

This option generates a function with arguments that allows chart code to be reused in the generated code of a model reference hierarchy that includes multiple instances of a chart across referenced models. In this case, the chart must be in a library.

Tips

When you want multiple instances of a chart represented as one reusable function, you can designate each one of them as Auto or as Reusable function. It is best to use one because using both creates two reusable functions, one for each designation. The outcomes of these choices differ only when reuse is not possible. Selecting Auto does not allow for control of the function or file name for the chart code.
The Reusable function and Auto options both try to determine if multiple instances of a chart exist and if the code can be reused. The difference between the options' behavior is that when reuse is not possible. In this case, Auto yields inlined code, or if circumstances prohibit inlining, separate functions for each chart instance.
If you select the Reusable function while your generated code is under source control, set File name options to Use subsystem name, Use function name, or User specified. Otherwise, the names of your code files change whenever you modify your model, which prevents source control on your files.

Dependency

This parameter requires Simulink Coder.
To enable this parameter, select Treat as atomic unit.
Setting this parameter to Nonreusable function or Reusable function enables the following parameters:
- Function name options
- File name options
- Memory section for initialize/terminate functions (requires Embedded Coder and an ERT-based system target file)
- Memory section for execution functions (requires Embedded Coder and an ERT-based system target file)
Setting this parameter to Nonreusable function enables Function with separate data (requires a license for Embedded Coder and an ERT-based system target file).

Programmatic Use

Parameter: RTWSystemCode

Type: character vector

Value: 'Auto' | 'Inline' | 'Nonreusable function' | 'Reusable function'

Default: 'Auto'

Model Examples

Home Climate Control Using the Truth-Table Block

Use the truth table block to control the temperature and humidity using a climate control system. The truth table block defines two possible boolean variables, Hot and Dry. Stateflow® sets these states if input variables reach defined temperature and humidity thresholds. The different state combinations result in different actions. For example, if both Hot and Dry are true, Stateflow executes the actions CoolOn and HumidOn.

Extended Capabilities

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

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.

Tunable Parameters

You can use a tunable parameter in a Truth Table intended for HDL code generation. For details, see Generate DUT Ports for Tunable Parameters (HDL Coder).

HDL Architecture

This block has a single, default HDL architecture.

HDL Block Properties

ConstMultiplierOptimization	Canonical signed digit (CSD) or factored CSD optimization. The default is `none`. See also ConstMultiplierOptimization (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).
DistributedPipelining	Pipeline register distribution, or register retiming. The default is `off`. See also DistributedPipelining (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).
InstantiateFunctions	Generate a VHDL^® `entity` or Verilog^® `module` for each function. The default is `off`. See also InstantiateFunctions (HDL Coder).
LoopOptimization	Unroll, stream, or do not optimize loops. The default is `none`. See also LoopOptimization (HDL Coder).
MapPersistentVarsToRAM	Map persistent arrays to RAM. The default is `off`. See also MapPersistentVarsToRAM (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).
ResetType	Suppress reset logic generation. The default is `default`, which generates reset logic. See also ResetType (HDL Coder).
SharingFactor	Number of functionally equivalent resources to map to a single shared resource. The default is 0. See also Resource Sharing (HDL Coder).
VariablesToPipeline	Warning `VariablesToPipeline` is not recommended. Use `coder.hdl.pipeline` (HDL Coder) instead. Insert a pipeline register at the output of the specified MATLAB variable or variables. Specify the list of variables as a character vector, with spaces separating the variables.

Documentation

Truth Table

Description

Ports

Input

u — Input port scalar | vector | matrix

Output

y — Output port scalar | vector | matrix

Parameters

Main

Show port labels — Select how to display port labels FromPortIcon (default) | FromPortBlockName | SignalName

Programmatic Use

Read/Write permissions — Select access to contents of chart ReadWrite (default) | ReadOnly | NoReadOrWrite

Programmatic Use

Treat as atomic unit — Control execution of a subsystem as one unit off (default) | on

Dependency

Programmatic Use

See also

Minimize algebraic loop occurrences — Control elimination of algebraic loops off (default) | on

Dependency

Programmatic Use

Sample time — Specify time interval -1 (default) | [Ts 0]

Dependency

Programmatic Use

Treat as grouped when propagating variant conditions — Control treating subsystem as unit on (default) | off

Programmatic Use

Code Generation

Function packaging — Select code format Auto (default) | Inline | Nonreusable function | Reusable function

Tips

Dependency

Programmatic Use

Model Examples

Home Climate Control Using the Truth-Table Block

Extended Capabilities

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

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

See Also

Topics

Stateflow Documentation

Support

`u` — Input port
scalar | vector | matrix

`y` — Output port
scalar | vector | matrix

`Show port labels` — Select how to display port labels
`FromPortIcon` (default) | `FromPortBlockName` | `SignalName`

`Read/Write permissions` — Select access to contents of chart
`ReadWrite` (default) | `ReadOnly` | `NoReadOrWrite`

`Treat as atomic unit` — Control execution of a subsystem as one unit
off (default) | on

`Minimize algebraic loop occurrences` — Control elimination of algebraic loops
off (default) | on

`Sample time` — Specify time interval
`-1` (default) | `[Ts 0]`

`Treat as grouped when propagating variant conditions` — Control treating subsystem as unit
`on` (default) | `off`

`Function packaging` — Select code format
`Auto` (default) | `Inline` | `Nonreusable function` | `Reusable function`

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

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