Serial Receive

R2026b

Receive data fromArduPilot serial (SCI) port

Since R2026b

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  • Serial Receive

Libraries:
UAV Toolbox Support Package for ArduPilot Autopilots / Peripheral Blocks

Description

Add-On Required: This feature requires the UAV Toolbox Support Package for ArduPilot Autopilots add-on.

The Serial Receive block receives data from a selected ArduPilot® serial communication interface (SCI) port. The block outputs the received values as an N-by-1 array.

Use this block when your model needs to receive serial data from ArduPilot supported hardware and process that data within a Simulink® workflow.

The Serial Receive block is supported only on ArduPilot based flight controllers. The block is not supported for SITL board configuration or ArduPilot Host Target autopilot configuration.

Note

When you use this block to receive serial data, set the SERIALx_PROTOCOL parameter of the ArduPilot autopilot to an unused protocol value. For instance, using Mission Planner, set the parameter to 55. When SERIALx_PROTOCOL has its default value, ArduPilot assigns a built-in driver to the port and the serial block cannot access it.

Examples

Getting Started with ArduPilot Serial Receive and Transmit Blocks

Getting Started with ArduPilot Serial Receive and Transmit Blocks

Configure two ArduPilot® telemetry ports for bidirectional loopback communication using Serial Transmit and Serial Receive blocks in Simulink®.

Send and Receive Custom Frame-Based Serial Data with ArduPilot

Send and Receive Custom Frame-Based Serial Data with ArduPilot

Send and receive custom frame-based serial data between a host computer and an ArduPilot® flight controller using the UAV Toolbox Support Package for ArduPilot Autopilots®. The example uses a request-response protocol in which a MATLAB® script on the host computer sends a data request, and the flight controller responds with the requested attitude or angular velocity data.

Ports

Output

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The port outputs data received from the selected serial (SCI) port. The number of elements in the output is determined by the Data Length parameter.

For more information about the structure of this output, see Partially Receive Data from Serial Port and Receive Data from Serial port .

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

The port outputs the receive status when the Output partial data parameter is disabled.

  • 0 — Successful receive operation

  • 1 — Length of received data is less than the specified data length

The port outputs the number of bytes received.

Dependencies

To enable this parameter, select the Output partial data parameter.

Parameters

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Select the serial port that the block uses to communicate between the target hardware and the external serial device. The available options depend on the serial port labels supported by the target hardware configuration. To verify the mapping between the logical port name and the physical port label, check the hardware board configuration set.

The selected serial port is supported only when you build and deploy the model to hardware. In Monitor & Tune(external mode) or Connected IO, the USB is reserved for communication between Simulink and the target hardware and cannot be used by this block.

Dependencies

To enable this parameter, disable the Select logical serial port parameter.

Programmatic Use

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

Parameter: SerialPortLabel
Values: USB | TELEM1 | TELEM2 | TELEM3 | GPS1 | GPS2 | GPS | GPS MODULE | UART4 & I2CB
Data Types: string | char

When you select this parameter, the Serial logical port parameter becomes available.

Programmatic Use

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

Parameter: SelectLogicalPort
Values: off | on
Data Types: string | char

Select the logical serial port. The logical port name maps to a numeric SCI module. In Monitor & Tune(external mode) or Connected IO, the USB is reserved for communication between Simulink and the target hardware and cannot be used by this block.

Dependencies

To enable this parameter, select the Select logical serial port parameter.

Programmatic Use

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

Parameter: LogicalPortList
Values: Serial 0 (default) | Serial 1 | Serial 2 | Serial 3 | Serial 4 | Serial 5 | Serial 6 | Serial 7 | Serial 8
Data Types: string | char

Select the data type of the received data.

Programmatic Use

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

Parameter: DataType
Values: uint8 (default) | int8 | uint16 | int16 | uint32 | int32 | single | double
Data Types: numeric

Select this parameter to enable the Length port, which outputs the number of received elements.

Programmatic Use

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

Parameter: PartialData
Values: off (default) | on
Data Types: string | char

Specify the number of bytes to receive at each sample time.

Programmatic Use

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

Parameter: DataLength
Values: 1 (default) | any integer greater than or equal to 0
Data Types: string | char

When you specify -1, Simulink determines the best sample time based on the block context within the model.

Programmatic Use

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

Parameter: SampleTime
Values: -1 (default) | positive scalar
Data Types: string | char

Partially Receive Data from Serial Port

This section describes the values at the Length output port when the number of bytes received is less than, greater than, or equal to the length of Data length parameter. For this example, suppose that you have set Data type to uint8 and Data length to 4. Suppose also that you have selected Output partial data and the block is operating in nonblocking mode.

  • Length of data received = Data length : The Data port outputs the message as a vector of the size specified in the Data length parameter.

    Suppose that the Data length parameter specified is 4 and the length of the message received is also 4.

    In this case, the Data port outputs a data vector of size 4 filled with the data bytes of the message, and the Length port outputs 4.

    Length of message received is equal to Data length

  • Length of data received < Data length : The Data port outputs the message as a data vector of the size specified in the Data length parameter. All the empty spaces in the vector are filled with zeroes.

    Suppose that the Data length parameter specified is 4 and the length of data received is 3 bytes.

    In this case, the Data port outputs a data vector of size 4. The first three data bytes in the vector are the bytes from the received message; the remaining space is filled with zero. The Length port outputs 3.

    Length of message received is less than Data length

  • Length of data received > Data length : The Data port outputs a data vector of the size specified in the Data length parameter. The vector contains only the first N data bytes from the message. The remaining data bytes are left in the buffer.

    Suppose that the Data length parameter specified is 4 and the length of data received is 5 bytes. In this case, the port outputs a data vector of size 4. The vector contains only the first 4 bytes from the received data. The remaining data byte is left in the buffer. The Length port outputs 4.

    Length of message received is greater than Data length

Receive Data from Serial port

This example describes the values at the Status output port when the length of the messages received is less than, greater than, or equal to the length of requested data. This section explains the values at the output ports, with Data type set to uint8 and Data length set to 4 in blocking and non-blocking modes.

  • Length of data received = Data length: The Data port outputs the message as a data vector of the size specified in the Data length parameter.

    Suppose that the Data length parameter specified is 4 and the length of the message received is also 4.

    In this case, for both blocking and non-blocking modes, the Data port outputs a data vector of size 4 filled with the data bytes of the message, and the Status port outputs 0.

    Length of message received is equal to Data length

  • Length of data received < Data length: The Data port outputs the message as a data vector of the size specified in the Data length parameter. All the empty spaces in the vector are filled with zeroes.

    Suppose that the Data length parameter specified is 4 and the length of data received is 3 bytes.

    For non-blocking mode, the Data port outputs a data vector of size 4. The first three data bytes in the vector are the bytes from the received message. The remaining space is filled with zero. The Status port outputs 1.

    For blocking mode, the block waits till all the data bytes are received within the time specified in the Timeout parameter. If the fourth data byte is not received within the timeout, the Data outputs zeroes, and the Status port outputs 1. The three received data bytes are left in the buffer.

    Length of message received is less than Data length

  • Length of data received > Data length : The Data port outputs a data vector of the size specified in the Data length parameter. The vector contains only the first N data bytes from the message. The remaining data bytes are left in the buffer.

    Suppose that the Data length parameter specified is 4 and the length of data received is 5 bytes. In this case, for both blocking and non-blocking modes, the port outputs a data vector of size 4. The vector contains only the first 4 bytes from the received data. The remaining data byte is left in the buffer. The Status port outputs zero.

    Length of message received is greater than Data length

Version History

Introduced in R2026b

See Also

Blocks