Logical Operator

Perform specified logical operation on input

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Libraries:
Simulink / Commonly Used Blocks
Simulink / Logic and Bit Operations
HDL Coder / Commonly Used Blocks
HDL Coder / Logic and Bit Operations

Description

The Logical Operator block performs the specified logical operation on its inputs. An input value is true (1) if it is nonzero and false (0) if it is zero.

You select the Boolean operation connecting the inputs with the Operator parameter list. If you select rectangular as the Icon shape property, the name of the selected operator displays on the block icon. If you select distinctive as the Icon shape property, the name of the selected operator does not display on the block icon. This table shows supported operations:

Operation	Description
AND	TRUE if all inputs are TRUE
OR	TRUE if at least one input is TRUE
NAND	TRUE if at least one input is FALSE
NOR	TRUE when no inputs are TRUE
XOR	TRUE if an odd number of inputs are TRUE
NXOR	TRUE if an even number of inputs are TRUE
NOT	TRUE if the input is FALSE

If you select distinctive as the Icon shape, the block appearance indicates its function. Simulink^® software displays a distinctive shape for the selected operator, conforming to the IEEE^® Standard Graphic Symbols for Logic Functions.

To specify the number of input ports, use the Number of input ports parameter. The output type is specified using the Output data type parameter. An output value is 1 if TRUE and 0 if FALSE.

Note

The output data type should represent zero exactly. Data types that satisfy this condition include signed and unsigned integers, and any floating-point data type.

The size of the output depends on input vector size and the selected operator:

• If the block has more than one input, any nonscalar inputs must have the same dimensions. For example, if any input is a 2-by-2 array, all other nonscalar inputs must also be 2-by-2 arrays.

  Scalar inputs are expanded to have the same dimensions as the nonscalar inputs.

  If the block has more than one input, the output has the same dimensions as the inputs (after scalar expansion) and each output element is the result of applying the specified logical operation to the corresponding input elements. For example, if the specified operation is AND and the inputs are 2-by-2 arrays, the output is a 2-by-2 array whose top left element is the result of applying AND to the top left elements of the inputs, and so on.

• For a single vector input, the block applies the operation (except the NOT operator) to all elements of the vector. The output is always a scalar.

• The NOT operator accepts only one input, which can be a scalar or a vector. If the input is a vector, the output is a vector of the same size containing the logical complements of the input vector elements.

When configured as a multi-input XOR gate, this block performs an addition modulo two operation as mandated by the IEEE Standard for Logic Elements.

Examples

Model Fault-Tolerant Fuel Control System

Combine Stateflow® and Simulink® capabilities 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 it detects individual sensor failures, and the control system is dynamically reconfigured for uninterrupted operation.

• Open Model

Model Stick-Slip Friction and Hard Stops in Mass-Spring-Damper System

One way you can incorporate hard stops and friction changes from stick-slip motion into a mass-spring-damper model.

• Open Live Script

Building a Clutch Lock-Up Model

Use Simulink® to model and simulate a rotating clutch system. Although modeling a clutch system is difficult because of topological changes in the system dynamics during lockup, this example shows how enabled subsystem can easily handle such problems. We illustrate how to employ important Simulink modeling concepts in the creation of the clutch simulation. Designers can apply these concepts to many models with strong discontinuities and constraints that may change dynamically.

• Open Model

Ports

Input

Port_1 — First input signal

scalar | vector | matrix

First input signal, specified as a scalar, vector, or matrix.

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Port_2 — Second input signal

scalar | vector | matrix

Second input signal, specified as a scalar, vector, or matrix.

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Port_N — Nth input signal

scalar | vector | matrix

Nth input signal, specified as a scalar, vector, or matrix.

Dependencies

To enable additional input ports, use the Number of input ports parameter.

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Output

Port_1 — Output signal

scalar | vector | matrix

Output signal, consisting of zeros and ones, with the same dimensions as the input. You control the output data type with the Require all inputs and output to have the same data type and Output data type parameters.

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Parameters

Main

Operator — Logical operator

AND (default) | OR | NAND | NOR | XOR | NXOR | NOT

Select the logical operator to apply to block inputs.

• AND — TRUE if all inputs are TRUE

• OR — TRUE if at least one input is TRUE

• NAND — TRUE if at least one input is FALSE

• NOR — TRUE when no inputs are TRUE

• XOR — TRUE if an odd number of inputs are TRUE

• NXOR — TRUE if an even number of inputs are TRUE

• NOT — TRUE if the input is FALSE

Programmatic Use

Block Parameter: Operator

Type: character vector

Values: 'AND' | 'OR' | 'NAND' | 'NOR' | 'XOR' | 'NXOR' | 'NOT'

Default: 'AND'

Number of input ports — Number of inputs

2 (default) | positive integer

Specify the number of block inputs as a positive integer.

Programmatic Use

Block Parameter: Inputs

Type: character vector

Values: positive integer

Default: '2'

Dependencies

This parameter is not available when you set the Operator to NOT.

Icon shape — Icon shape

rectangular (default) | distinctive

Specify the shape of the block icon.

• rectangular — Results in a rectangular block that displays the name of the selected operator.

• distinctive — Use the graphic symbol for the selected operator as specified by the IEEE standard.

Programmatic Use

Block Parameter: IconShape

Type: character vector

Values: 'rectangular' | 'distinctive'

Default: 'rectangular'

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

To set the block parameter value programmatically, use the set_param function.

Parameter:	SampleTime
Values:	"-1" (default) | scalar or vector in quotes

Data Type

Require all inputs and output to have the same data type — Require all ports to have same data type

off (default) | on

To require that all block inputs and the output have the same data type, select this check box. When you clear this check box, the inputs and output can have different data types.

Programmatic Use

Block Parameter: AllPortsSameDT

Type: character vector

Values: 'off' | 'on

Default: 'off'

Output data type — Output data type

boolean (default) | Inherit: Logical (see Configuration Parameters: Optimization) | fixdt(1,16) | <data type expression>

Specify the output data type. When you select:

• boolean — The block output has data type boolean.

• Inherit: Logical (see Configuration Parameters: Optimization) — The block uses the Implement logic signals as Boolean data configuration parameter to specify the output data type (see Implement logic signals as Boolean data (vs. double)).

  Note

  This option supports models created before the boolean option was available. Use one of the other options, preferably boolean, for new models.

• fixdt(1,16) — The block output has the specified fixed-point data type fixdt(1,16).

  Tip

  The Data Type Assistant helps you set data attributes. To use the Data Type Assistant, click . For more information, see Specify Data Types Using Data Type Assistant.

• <data type expression> — The block output has the data type you specify as a data type expression, for example, Simulink.NumericType.

  Tip

  To enter a built-in data type (double, single, int8, uint8, int16, uint16, int32, or uint32), enclose the expression in single quotes. For example, enter 'double' instead of double.

Programmatic Use

Block Parameter: OutDataTypeStr

Type: character vector

Values: 'Inherit: Logical (see Configuration Parameters: Optimization)' | 'boolean' | 'fixdt(1,16)' | '<data type expression>'

Default: 'boolean'

Mode — Category of data to specify

Built in (default) | Inherit | Fixed point | Expression

Select the category of data to specify.

• Built in — Specifies built-in data types. Selecting Built in enables boolean.

• Inherit — Specifies inheritance rules for data types. Selecting Inherit enables Logical (see Configuration Parameters: Optimization).

• Fixed point — Specifies fixed-point data types.

• Expression — Specifies expressions that evaluate to data types.

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 — Signedness of fixed-point data

Signed (default) | Unsigned

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

Scaling — Method of scaling

Integer (default)

Specify the method for scaling your fixed-point data to avoid overflow conditions and minimize quantization errors. Specifying Integer has the same result as specifying a binary point location and setting the fraction length to 0.

Dependencies

To enable this parameter, click the Show data type assistant button and set Mode to Fixed point.

Block Characteristics

Data Types	Boolean | double | fixed point | half | integer | single
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 HDL implementation and synthesized logic.

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™.

Version History

Introduced before R2006a