Package com.diozero.api

Class SerialDevice

java.lang.Object

com.diozero.api.SerialDevice

All Implemented Interfaces:

DeviceInterface, SerialConstants, SerialDeviceInterface, AutoCloseable

public class SerialDevice
extends Object
implements SerialConstants, SerialDeviceInterface

Serial device. The SerialDevice represents serial devices connected via USB or via the serial RX/TX pins on the GPIO header.

On the Raspberry Pi, to use the serial RX/TX pins on the GPIO header, the serial interface must be enabled and the login shell must be disabled. The device file name for the serial RX/TX pins is /dev/serial0. See Raspberry Pi UART configuration for additional detail.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SerialDevice.Builder	Serial device builder.
static class	SerialDevice.DeviceInfo	Provides descriptive information for a connected serial device.

Nested classes/interfaces inherited from interface com.diozero.api.SerialConstants

SerialConstants.DataBits, SerialConstants.Parity, SerialConstants.ReadMode, SerialConstants.StopBits

Field Summary

Fields inherited from interface com.diozero.api.SerialConstants

BAUD_1000000, BAUD_110, BAUD_115200, BAUD_1152000, BAUD_1200, BAUD_134, BAUD_150, BAUD_1500000, BAUD_1800, BAUD_19200, BAUD_200, BAUD_2000000, BAUD_230400, BAUD_2400, BAUD_2500000, BAUD_300, BAUD_3000000, BAUD_3500000, BAUD_38400, BAUD_4000000, BAUD_460800, BAUD_4800, BAUD_50, BAUD_500000, BAUD_57600, BAUD_576000, BAUD_600, BAUD_921600, BAUD_9600, BAUD_B75, DEFAULT_BAUD, DEFAULT_DATA_BITS, DEFAULT_MIN_READ_CHARS, DEFAULT_PARITY, DEFAULT_READ_BLOCKING, DEFAULT_READ_TIMEOUT_MILLIS, DEFAULT_STOP_BITS, READ_TIMEOUT

Constructor Summary

Constructors

Constructor	Description
SerialDevice(String deviceFilename)	Create a new serial device using default values for baud, data bits, stop bits, parity, read blocking, min read chars and read timeout
SerialDevice(String deviceFilename, int baud, SerialConstants.DataBits dataBits, SerialConstants.StopBits stopBits, SerialConstants.Parity parity)	Create a new serial device using default values for read blocking, min read chars and read timeout

Method Summary

Modifier and Type	Method	Description
static SerialDevice.Builder	builder(String deviceFilename)
int	bytesAvailable()	Get the number of bytes that are available to be read
void	close()	Close this device
String	getDeviceFilename()	Get the device filename
static List<SerialDevice.DeviceInfo>	getLocalSerialDevices()	Attempt to discover the locally attached serial devices using Linux device tree.
int	read()	Read a single byte returning error responses
int	read(byte[] buffer)	Attempt to read buffer.length bytes into the specified buffer, returning the number of bytes actually read; throw a RuntimeIOException if an I/O error occurs
byte	readByte()	Read a single byte, throw an exception if unable to read any data
void	write(byte... buffer)	Write the byte buffer to the device
void	writeByte(byte bVal)	Write a single byte, throw an exception if unable to write the data

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

SerialDevice

public SerialDevice(String deviceFilename)
             throws RuntimeIOException

Create a new serial device using default values for baud, data bits, stop bits, parity, read blocking, min read chars and read timeout

Parameters:

deviceFilename - The O/S file name for the device, e.g. /dev/ttyACM0

Throws:

RuntimeIOException - If an I/O error occurs

SerialDevice

public SerialDevice(String deviceFilename,
int baud,
SerialConstants.DataBits dataBits,
SerialConstants.StopBits stopBits,
SerialConstants.Parity parity)
             throws RuntimeIOException

Create a new serial device using default values for read blocking, min read chars and read timeout

Parameters:

deviceFilename - The O/S file name for the device, e.g. /dev/ttyACM0

baud - Baud rate, see SerialConstants for valid baud rate values

dataBits - Number of data bits

stopBits - Number of stop bits

parity - Device error detection parity

Throws:

RuntimeIOException - If an I/O error occurs

Method Details

getLocalSerialDevices

public static List<SerialDevice.DeviceInfo> getLocalSerialDevices()

Attempt to discover the locally attached serial devices using Linux device tree.

Returns:

A list of locally attached devices

builder

public static SerialDevice.Builder builder(String deviceFilename)

getDeviceFilename

public String getDeviceFilename()

Get the device filename

Returns:

the device filename, e.g. /dev/ttyUSB0

close

public void close()

Close this device

Specified by:

close in interface AutoCloseable

Specified by:

close in interface DeviceInterface

read

public int read()
         throws RuntimeIOException

Read a single byte returning error responses

Specified by:

read in interface SerialDeviceInterface

Returns:

Signed integer representation of the data read, including error responses (values < 0)

Throws:

RuntimeIOException - if an I/O error occurs

readByte

public byte readByte()
              throws RuntimeIOException

Read a single byte, throw an exception if unable to read any data

Specified by:

readByte in interface SerialDeviceInterface

Returns:

The data read

Throws:

RuntimeIOException - if an I/O error occurs

writeByte

public void writeByte(byte bVal)
               throws RuntimeIOException

Write a single byte, throw an exception if unable to write the data

Specified by:

writeByte in interface SerialDeviceInterface

Parameters:

bVal - The data to write

Throws:

RuntimeIOException - if an I/O error occurs

read

public int read(byte[] buffer)
         throws RuntimeIOException

Attempt to read buffer.length bytes into the specified buffer, returning the number of bytes actually read; throw a RuntimeIOException if an I/O error occurs

Specified by:

read in interface SerialDeviceInterface

Parameters:

buffer - The buffer to read into, the length of this buffer specifies the number of bytes to read

Returns:

The number of bytes read

Throws:

RuntimeIOException - if an I/O error occurs

write

public void write(byte... buffer)
           throws RuntimeIOException

Write the byte buffer to the device

Specified by:

write in interface SerialDeviceInterface

Parameters:

buffer - The data to write

Throws:

RuntimeIOException - if an I/O error occurs

bytesAvailable

public int bytesAvailable()
                   throws RuntimeIOException

Get the number of bytes that are available to be read

Specified by:

bytesAvailable in interface SerialDeviceInterface

Returns:

The number of bytes that are available to read

Throws:

RuntimeIOException - if an I/O error occurs