Serial Receive

Receive binary data over serial port

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Libraries:
Instrument Control Toolbox
Motor Control Blockset / Protection and Diagnostics

Description

The Serial Receive block configures and opens an interface to the specified serial port. The configuration and initialization occur once at the start of the model's execution. The block acquires data from the serial port during the model's run time. You can use only one Serial Receive block at a time to receive data from a specific serial port.

Note

You must configure your serial port parameters using the Serial Configuration block before you specify the Serial Receive block parameters.

This block has no input ports. It has one or two output ports based on whether you select blocking or non-blocking mode. If you select blocking mode, the block has one output port, Data, corresponding to the data it receives. If you do not select blocking mode, the block has two output ports, Data and Status.

This block uses a First In, First Out (FIFO) buffer to receive data from the serial port. At each time step, the Data port returns the requested values from the buffer. In non-blocking mode, the Status port indicates if the block has received new data. If the Status port displays 1, new data is available and if the Status port displays 0, no new data is available.

Other Supported Features

• The Serial Receive block supports the use of Simulink^® Accelerator mode, but not Rapid Accelerator. This feature speeds up the execution of Simulink models.

• The Serial Receive block supports the use of model referencing. This feature lets your model include other Simulink models as modular components.

• The Serial Receive block supports C/C++ code generation. This feature allows you to generate C and C++ code using Simulink Coder™.

For more information on these features, see the Simulink documentation.

Ports

Output

Data — Data received

vector | matrix | array

Data received by the block from the serial port, returned as a vector, matrix, or array.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32

Status — New data available

false or 0 (default) | true or 1

New data available status, returned as numeric or logical 1 (true) or 0 (false). If this port returns 1, new data is available to be read.

Dependencies

To enable this port, unselect the Enable blocking mode parameter.

Data Types: Boolean

Parameters

Port — Serial communication port

available communication ports

Serial port on your machine that you want to receive data from. Select a port from the available ports and then configure the port using the Serial Configuration block. If you have not configured a port, the block returns an error when you run your model.

Note

Each Serial Receive block must have a configured Serial Configuration block. If you use multiple serial ports in your simulation, you must configure each port using a separate Serial Configuration block.

Programmatic Use

Block Parameter: Port

Type: character vector, string

Data type — Output data type

uint8 (default) | single | double | int8 | int16 | uint16 | int32 | uint32

Data type that the block receives from the serial port, specified as a MATLAB^® numeric data type.

Programmatic Use

Block Parameter: DataType

Type: character vector, string

Values: 'uint8' | 'single' | 'double' | 'int8' | 'int16' | 'uint16' | 'int32' | 'uint32'

Default: 'uint8'

Header — Header

numeric array | integer from 0 to 255, inclusive

If this parameter is selected, you can specify the header that indicates the beginning of your data block. The simulation disregards data that occurs before the header. The header data is not sent to the output port. By default, this parameter is not selected and no header is specified.

The numeric array specified in this parameter is the uint8 integer representation of the corresponding ASCII characters. The exact form of this parameter depends on the type of the ASCII character.

Type of ASCII Character	Example ASCII Character	MATLAB Command	Parameter Value
Special character	"#"	uint8('#')	[35]
Numeric	"81"	uint8('81')	[56 49]
Alphabet	"Start"	uint8('Start')	[83 116 97 114 116]

You can also specify this parameter using the hexadecimal representation of the ASCII characters.

Programmatic Use

Block Parameter: ToggleHeader

Type: character vector, string

Values: 'on' | 'off'

Default: 'off'

Block Parameter: Header

Type: character vector, string

Values: integer array

End token — Terminator

<none> (default) | CR ('\r') | LF ('\n') | CR/LF ('\r\n') | NULL ('\0') | Custom Terminator

If this parameter is selected, you can specify the end token or terminator that indicates the end of your data block. The simulation considers any data that occurs after the end token as a new data block. The end token data is not sent to the output port. This end token must match the one in the data you are reading from your serial port, if it has one.

If you select Custom Terminator, you can specify your own end token value.

Programmatic Use

Block Parameter: ToggleTerminator

Type: character vector, string

Values: 'on' | 'off'

Default: 'off'

Block Parameter: Terminator

Type: character vector, string

Values: '<none>' | 'CR ('\r')' | 'LF ('\n')' | 'CR/LF ('\r\n')' | 'NULL ('\0')' | 'Custom Terminator'

Default: '<none>'

Custom terminator — Custom terminator

numeric array | integer from 0 to 255, inclusive

Custom terminator that indicates the end of your data block, used when End token is set to 'Custom Terminator'. The simulation considers any data that occurs after the terminator as a new data block. The terminator data is not sent to the output port.

The numeric array specified in this parameter is the uint8 integer representation of the corresponding ASCII characters. The exact form of this parameter depends on the type of the ASCII character.

Type of ASCII Character	Example ASCII Character	MATLAB Command	Parameter Value
Special character	"#"	uint8('#')	[35]
Numeric	"81"	uint8('81')	[56 49]
Alphabet	"End"	uint8('End')	[69 110 100]

You can also specify this parameter using the hexadecimal representation of the ASCII characters.

Programmatic Use

Block Parameter: CustomTerminator

Type: character vector, string

Values: integer array

Input Format — Format of data read

Column major (default) | Row major

Format of the data that the block receives from the serial port, specified as Row major or Column major.

Programmatic Use

Block Parameter: InputFormat

Type: character vector, string

Values: 'Row major' | 'Column major'

Default: 'Column major'

Data size — Number of values read

[1 1] (default) | numeric array

Output data size, or the number of values that should be read at each simulation time step. This parameter is specified as a multidimensional numeric array. The data size does not include the header or terminator values.

Programmatic Use

Block Parameter: DataSize

Type: character vector, string

Values: integer array

Default: '[1 1]'

Enable blocking mode — Simulation waits while receiving data

on (default) | off

This parameter has the simulation wait while the block receives data. When new data becomes available, the simulation continues from the next time step. Unselect the check box if you do not want the read operation to cause the simulation to wait.

If you enable blocking mode, the simulation waits for the requested data to become available. The model waits for up to the amount of time specified by the Timeout parameter in the Serial Configuration block. If new data does not become available during a simulation, you can return an error by selecting the Error option for the Action when data is not available parameter.

If you do not enable blocking mode, the simulation runs continuously and the block has two output ports, Status and Data. The Data port contains the requested set of data at each time step. The Status port contains 0 or 1 based on whether it received new data at the given time step.

Programmatic Use

Block Parameter: EnableBlockingMode

Type: character vector, string

Values: 'on' | 'off'

Default: 'on'

Action when data is not available — Action to take when data not available

Output last received value (default) | Output custom value | Error

Action the block should take when data is not available. Available options are:

• Output last received value — Block returns the value it received at the preceding time step when it does not receive data at current time step.

• Output custom value — Block returns any user-defined value when it does not receive current data. Define the custom value in the Custom value field.

• Error — Block returns an error when it does not receive current data. You must select Enable blocking mode to use this option.

Programmatic Use

Block Parameter: ActionDataUnavailable

Type: character vector, string

Values: 'Output last received value' | 'Output custom value' | 'Error'

Default: 'Output last received value'

Custom value — Custom output value when data unavailable

0 (default) | numeric

Custom value for the block to output when it does not receive new data. The custom value can be a scalar or value equal to the size of data that it receives (specified by Data size parameter). You must select Output custom value as the Action when data is unavailable to set this parameter.

Programmatic Use

Block Parameter: CustomValue

Type: character vector, string

Values: numeric

Default: '0'

Block sample time — Sampling time

0.01 (default) | positive numeric

Sampling time of the block during the simulation. This is the rate at which the block is executed during simulation.

Programmatic Use

Block Parameter: SampleTime

Type: character vector, string

Values: positive numeric

Default: '0.01'

Extended Capabilities

C/C++ Code Generation

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

This block generates platform-specific code for the host machine's platform only (Windows^®, macOS, Linux^®).

Version History

Introduced in R2008a