read

R2026b

Read data from serial device

Syntax

out = read(serialdevObj,numBytes)

out = read(serialdevObj,numBytes,precision)

Description

Add-On Required: This feature requires the MATLAB Support Package for Arduino Hardware add-on.

out = read(serialdevObj,numBytes) returns number of bytes of data read from serial device.

out = read(serialdevObj,numBytes,precision) also specifies the data precision.

Examples

Read Data from Serial Device on Arduino Hardware

Create an arduino connection.

arduinoObj = arduino("COM16","Leonardo","Libraries",{'SPI','Serial','I2C'});

Create a connection to the serial device on the Arduino hardware.

serialdevObj = device(arduinoObj,'SerialPort',1,'BaudRate', 115200, 'DataBits',8, 'StopBits', 1, 'Parity', 'even')

serialdevObj = 
  device with properties:

             Interface: 'Serial'
            SerialPort: 1
                 TxPin: 'D1'
                 RxPin: 'D0'
              BaudRate: 115200 (bits/s) 
     NumBytesAvailable: 0 

Show all properties, functions

Connect the Rx and Tx pins in loopback. Write 3 bytes of data to the serial device.

write(serialdevObj,[88 99 65]);

Check if data is available to read.

numBytes = serialdevObj.NumBytesAvailable

numBytes = 
3

Read data from the serial device.

read(serialdevObj,3)

ans = 1×3

    88    99    65

Specify Precision to Read Data from Serial Device on Arduino Hardware

Create an arduino connection

arduinoObj = arduino("COM16","Leonardo","Libraries",{'SPI','Serial','I2C'});

Create a connection to the serial device on the Arduino hardware.

serialdevObj = device(arduinoObj,'SerialPort',1,'BaudRate', 115200, 'DataBits',8, 'StopBits', 1, 'Parity', 'even')

serialdevObj = 
  device with properties:

             Interface: 'Serial'
            SerialPort: 1
                 TxPin: 'D1'
                 RxPin: 'D0'
              BaudRate: 115200 (bits/s) 
     NumBytesAvailable: 0 

Show all properties, functions

Connect the Rx and Tx pins in loopback. Write data to the serial device.

write(serialdevObj,256,'uint16');

Check if data is available to read.

numBytes = serialdevObj.NumBytesAvailable

numBytes = 
2

Read data from serial device with precision of uint16.

read(serialdevObj,1,'uint16')

ans = 
256

Input Arguments

serialdevObj — Serial device connection

device object

Serial device connection, specified as a device object.

numBytes — Number of bytes to read

scalar

Number of bytes of data to read from the serial device, specified as a scalar.

Note

For the Arduino^® Mega2560, Mega ADK, Leonardo, and Micro boards read works only for up to 63 bytes of data as the Arduino libraries do not read data into last byte of serial receive buffer. See this link for more details.

precision — Data precision

'uint8' (default) | 'int8' | 'uint16' | 'int16' | 'uint32' | 'int32' | 'uint64' | 'int64'

Data precision, specified as one of the following character vectors:

• 'uint8'

• 'int8'

• 'uint16'

• 'int16'

• 'uint32'

• 'int32'

• 'uint64'

• 'int64'

Output Arguments

out — Data read from serial device

scalar | vector

Data read from serial device, returned as a scalar or vector based on the precision.

More About

Code Generation Using MATLAB Function Block

• Use read in a MATLAB^® Function block with the Simulink^® Support Package for Arduino Hardware to generate code that can be deployed on Arduino Hardware.

Alternative Functionality

App

Use Arduino Explorer to configure serial device and then read data from it. You can use the app in the installed version of MATLAB and MATLAB Online™. You can also use the Plot pane of the app to interactively view data read from the Arduino board. For more information, see Connect to Serial Device Using Arduino Explorer App.

Version History

Introduced in R2019b