read

Read data from serial device

Description

example

serialData = read(myserialdevice,count) returns data from the serial device.

The read method stops when it finishes reading the specified data from the device, or when the timeout period elapses.

example

serialData = read(myserialdevice,count,precision) overrides the default value for precision.

Examples

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You can connect to a serial device from the MATLAB® software, write data to the device, and read data from the device.

Create a connection from the MATLAB software to the Raspberry Pi™ hardware.

mypi = raspi

Show the location of the Tx and Rx pins, GPIO 14 (UART0_TXD) and GPIO 15 (UART0_RXD), on the GPIO header.

showPins(mypi)

Raspberry Pi hardware uses +3.3 V. Do not connect Raspberry Pi hardware directly to devices that use higher voltages.

Connect the Raspberry Pi serial port to a +3.3 V serial device.

  • To receive data, connect the RXD pin (GPIO 15 UART0_RXD) on the Raspberry Pi board to the TXD pin on the serial device.

  • To transmit data, connect the TXD pin (GPIO 14 UART0_TXD) on the Raspberry Pi board to the RXD pin on the serial device.

  • Connect a ground pin (GND) on the Raspberry Pi board to the GND pin on the serial device.

  • Connect one of the +3.3 V pins on the Raspberry Pi board to the VCC pin on the serial device.

Research the values the serial device requires for baud, data bits, parity, and stop bit.

Create a connection, myserialdevice, from the MATLAB software to the serial device.

myserialdevice = serialdev(mypi,'/dev/ttyAMA0',9600)
myserialdevice = 

  Serialdev with Properties:

    BaudRate: 9600
    DataBits: 8
      Parity: 'none'
    StopBits: 1
     Timeout: 10

Write a pair of values to a serial device that requires a specific data type.

write(myserialdevice,[10 12],'uint16')

Read a 100-element array of numbers from the serial port.

output = read(myserialdevice,100,'uint16')

Increase the timeout period of the serial port.

myserialdevice.Timeout = 20
myserialdevice = 

  Serialdev with Properties:

    BaudRate: 115200
    DataBits: 8
      Parity: 'none'
    StopBits: 1
     Timeout: 20

Input Arguments

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Connection to a serial device, specified as a serialdev object.

Example: myserialdevice

Data size to read from the serial device, specified as a scalar.

Example: 2

Data Types: double

Data precision, specified as a string. Optional.

Example: 'uint8'

Data Types: char

Output Arguments

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Data from the serial device, returned in the device- or user-defined format.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.