serialdev

Connection to serial device on Raspberry Pi hardware

Description

This object represents a connection from the MATLAB^® software to a serial device on the Raspberry Pi™ hardware. To exchange data with the serial device, use this object with the functions listed in Object Functions.

Creation

Syntax

myserialdevice = serialdev(mypi,port)

myserialdevice = serialdev(mypi,port,baudRate,dataBits,parity,stopBits)

Description

myserialdevice = serialdev(mypi,port) creates a connection, myserialdevice, from the MATLAB software to the serial device on the Raspberry Pi hardware.

On the Raspberry Pi hardware, the /boot/cmdline.txt file configures /dev/ttyAMA0 as the serial device and sets the default baud to 115200. The serial device connects to the Rx and Tx pins on the GPIO header.

By default, the serial console in the customized version of Raspbian Wheezy on your Raspberry Pi hardware is disabled. To use serialdev, disable the serial console.

myserialdevice = serialdev(mypi,port,baudRate,dataBits,parity,stopBits) creates a connection from the MATLAB software to the serial device on the Raspberry Pi hardware using optional arguments to override the default values for baud, data bits, parity, and stop bits.

Input Arguments

mypi — Connection to specific Raspberry Pi hardware board

raspi object

Connection to a specific Raspberry Pi hardware board, specified as a raspi object.

port — Serial device port name

character vector

The name of the serial port that is connected to the BeagleBone^® Black hardware, specified as a character vector.

Example: '/dev/ttyO1'

Data Types: char

Properties

BaudRate — Serial device baud

115200 (default) | 50 | 75 | 110 | 134 | 150 | 200 | 300 | 600 | 1200 | 1800 | 2400 | 4800 | 9600 | 19200 | 38400 | 57600 | 230400

This property is read-only.

The rate at which the data is transferred over the serial line, specified as a scalar. The baud is measured in seconds. This property is set by the baudRate input argument. If not specified as an input argument, it takes the default value. It cannot be changed after object creation.

Example: 9600

Data Types: double

DataBits — Data bits per character

8 (default) | 5 | 6 | 7 | 9

This property is read-only.

The number of bits per character, specified as a scalar. This property is set by the dataBits input argument. If not specified as an input argument, it takes the default value. It cannot be changed after object creation.

Example: 8

Data Types: double

Parity — Parity bit for error detection

'none' (default) | 'odd' | 'even' | 'mark' | 'space'

This property is read-only.

The type of parity bit to be added to the data, specified as a character vector.

A parity bit is used to detect error in data transmission.

• 'none' – No parity is used for error detection in the data transmission.

• 'odd' – The data bits plus the parity bit produce an odd number of 1s.

• 'even' – The data bits plus the parity bit produce an even number of 1s.

• 'mark' – The parity bit is always 1.

• 'space' – The parity bit is always 0.

This property is set by the parity input argument. If not specified as an input argument, it takes the default value. It cannot be changed after object creation.

Example: 'none'

Data Types: char

StopBits — Stop bits

1 (default) | 1.5 | 2

This property is read-only.

The number of bits used as the stop bit in the data transmission. A stop bit marks the end of a unit of transmission. This property is set by the stopBits input argument. If not specified as an input argument, it takes the default value. It cannot be changed after object creation.

Example: 1

Data Types: double

TimeOut — Serial device timeout

10 (default) | positive real scalar

The waiting time in seconds to complete the object creation, specified as a positive value of type double.

Example: 10

Data Types: double

Object Functions

read	Read data from serial device
write	Write data to serial device

Examples

Connect to and Exchange Data with Serial Device

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

Extended Capabilities

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