Bit Clear

R2026b

Set specified bit of stored integer to zero

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Bit Clear block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Simulink / Logic and Bit Operations

Description

The Bit Clear block sets the specified bit, given by its index, of the stored integer to zero. The block ignores scaling.

You can specify the bit to be set to zero with the Index of bit parameter, where bit zero is the least significant bit.

Examples

Using a Bit Clear Block

This examples shows how to use the Bit Clear block to set the value of a specified bit index to 0.

A vector of constants 2.^[0 1 2 3 4] is represented in binary as [00001 00010 00100 01000 10000].

Open BitSetModel.slx and explore the Constant block and Bit Set block settings.

open_system('BitClearModel');

Simulate the model.

sim('BitClearModel');

With the index set to 2, the result is [00001 00010 00000 01000 10000], which is represented in decimal as [1 2 0 8 16] in the Display block.

Copyright 2018-2025, The MathWorks, Inc.

Ports

The Bit Clear block supports Simulink^® integer, fixed-point, and Boolean data types. The block does not support true floating-point data types or enumerated data types.

Input

Port_1 — Input signal

scalar | vector

The input signal is the specified bit of the stored integer.

Data Types: int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point | bus

Output

Port_1 — Output signal

scalar | vector

The output consists of the specified bit set to zero.

Data Types: int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Parameters

Index of bit — Index of bit

0 (default) | scalar | vector

Index of bit where bit 0 is the least significant bit.

Programmatic Use

Block Parameter: iBit

Type: character vector

Values: scalar | vector

Default: '0'

Block Characteristics

Data Types	Booleana | fixed point | integer
Direct Feedthrough	yes
Multidimensional Signals	yes
Variable-Size Signals	no
Zero-Crossing Detection	no
a Bit operations are not recommended for use with Boolean signals.

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"simulink/Logic and Bit Operations/Bit Clear"

Example: add_block("simulink/Logic and Bit Operations/Bit Clear","myModel/myBlock",MakeNameUnique="on")

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 in the design. Distributed pipelining does not redistribute these registers. The default value 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 value 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 value is 0. For more details, see OutputPipeline (HDL Coder).
SynthesisAttributes	Specifies the synthesis attributes for the blocks and block output signals in the model. The generated HDL code contains these attributes. For more information, see SynthesisAttributes (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

R2026a: Specify synthesis attributes for blocks and block output signals

Use the SynthesisAttributes HDL block property to specify the synthesis attributes for the block and its output signals. HDL Coder includes these attributes in the generated HDL code.