Package com.pi4j.io.i2c.impl

Class I2CDeviceImpl

java.lang.Object

com.pi4j.io.i2c.impl.I2CDeviceImpl

All Implemented Interfaces:

I2CDevice

public class I2CDeviceImpl
extends Object
implements I2CDevice

Implementation of i2c device. This class only holds reference to i2c bus (so it can use its handle) and device address.

Author:

Daniel Sendula, refactored by RasPelikan

Constructor Summary

Constructors

Constructor	Description
I2CDeviceImpl(I2CBusImpl bus, int address)	Constructor.

Method Summary

Modifier and Type	Method	Description
int	getAddress()
void	ioctl(long command, int value)	Runs an ioctl on this device.
void	ioctl(long command, ByteBuffer data, IntBuffer offsets)	Runs an ioctl on this device.
protected String	makeDescription()	This helper method creates a string describing bus file name and device address (in hex).
protected String	makeDescription(int address)	This helper method creates a string describing bus file name, device address (in hex) and local i2c address.
int	read()	This method reads one byte from the i2c device.
int	read(byte[] data, int offset, int size)	This method reads bytes from the i2c device to given buffer at asked offset.
int	read(byte[] writeData, int writeOffset, int writeSize, byte[] readData, int readOffset, int readSize)	This method writes and reads bytes to/from the i2c device in a single method call
int	read(int address)	This method reads one byte from the i2c device.
int	read(int address, byte[] data, int offset, int size)	This method reads bytes from the i2c device to given buffer at asked offset.
void	write(byte data)	This method writes one byte to i2c device.
void	write(byte[] buffer)	This method writes all bytes included in the given buffer directly to the i2c device.
void	write(byte[] data, int offset, int size)	This method writes several bytes to the i2c device from given buffer at given offset.
void	write(int address, byte data)	This method writes one byte to i2c device.
void	write(int address, byte[] buffer)	This method writes all bytes included in the given buffer directory to the register address on the i2c device
void	write(int address, byte[] data, int offset, int size)	This method writes several bytes to the i2c device from given buffer at given offset.

Methods inherited from class java.lang.Object

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

Constructor Detail

I2CDeviceImpl

public I2CDeviceImpl(I2CBusImpl bus,
                     int address)

Constructor.

Parameters:

bus - i2c bus

address - i2c device address

Method Detail

getAddress

public int getAddress()

Specified by:

getAddress in interface I2CDevice

Returns:

The address for which this instance is constructed for.

write

public void write(byte data)
           throws IOException

This method writes one byte to i2c device.

Specified by:

write in interface I2CDevice

Parameters:

data - byte to be written

Throws:

IOException - thrown in case byte cannot be written to the i2c device or i2c bus

write

public void write(byte[] data,
                  int offset,
                  int size)
           throws IOException

This method writes several bytes to the i2c device from given buffer at given offset.

Specified by:

write in interface I2CDevice

Parameters:

data - buffer of data to be written to the i2c device in one go

offset - offset in buffer

size - number of bytes to be written

Throws:

IOException - thrown in case byte cannot be written to the i2c device or i2c bus

write

public void write(byte[] buffer)
           throws IOException

This method writes all bytes included in the given buffer directly to the i2c device.

Specified by:

write in interface I2CDevice

Parameters:

buffer - buffer of data to be written to the i2c device in one go

Throws:

IOException - thrown in case byte cannot be written to the i2c device or i2c bus

write

public void write(int address,
                  byte data)
           throws IOException

This method writes one byte to i2c device.

Specified by:

write in interface I2CDevice

Parameters:

address - local address in the i2c device

data - byte to be written

Throws:

IOException - thrown in case byte cannot be written to the i2c device or i2c bus

write

public void write(int address,
                  byte[] data,
                  int offset,
                  int size)
           throws IOException

This method writes several bytes to the i2c device from given buffer at given offset.

Specified by:

write in interface I2CDevice

Parameters:

address - local address in the i2c device

data - buffer of data to be written to the i2c device in one go

offset - offset in buffer

size - number of bytes to be written

Throws:

IOException - thrown in case byte cannot be written to the i2c device or i2c bus

write

public void write(int address,
                  byte[] buffer)
           throws IOException

This method writes all bytes included in the given buffer directory to the register address on the i2c device

Specified by:

write in interface I2CDevice

Parameters:

address - local address in the i2c device

buffer - buffer of data to be written to the i2c device in one go

Throws:

IOException - thrown in case byte cannot be written to the i2c device or i2c bus

read

public int read()
         throws IOException

This method reads one byte from the i2c device. Result is between 0 and 255 if read operation was successful, else a negative number for an error.

Specified by:

read in interface I2CDevice

Returns:

byte value read: positive number (or zero) to 255 if read was successful. Negative number if reading failed.

Throws:

IOException - thrown in case byte cannot be read from the i2c device or i2c bus

read

public int read(byte[] data,
                int offset,
                int size)
         throws IOException

This method reads bytes from the i2c device to given buffer at asked offset.

Note: Current implementation calls read(int). That means for each read byte i2c bus will send (next) address to i2c device.

Specified by:

read in interface I2CDevice

Parameters:

data - buffer of data to be read from the i2c device in one go

offset - offset in buffer

size - number of bytes to be read

Returns:

number of bytes read

Throws:

IOException - thrown in case byte cannot be read from the i2c device or i2c bus

read

public int read(int address)
         throws IOException

This method reads one byte from the i2c device. Result is between 0 and 255 if read operation was successful, else a negative number for an error.

Specified by:

read in interface I2CDevice

Parameters:

address - local address in the i2c device

Returns:

byte value read: positive number (or zero) to 255 if read was successful. Negative number if reading failed.

Throws:

IOException - thrown in case byte cannot be read from the i2c device or i2c bus

read

public int read(int address,
                byte[] data,
                int offset,
                int size)
         throws IOException

This method reads bytes from the i2c device to given buffer at asked offset.

Note: Current implementation calls read(int). That means for each read byte i2c bus will send (next) address to i2c device.

Specified by:

read in interface I2CDevice

Parameters:

address - local address in the i2c device

data - buffer of data to be read from the i2c device in one go

offset - offset in buffer

size - number of bytes to be read

Returns:

number of bytes read

Throws:

IOException - thrown in case byte cannot be read from the i2c device or i2c bus

ioctl

public void ioctl(long command,
                  int value)
           throws IOException

Description copied from interface: I2CDevice

Runs an ioctl on this device.

Specified by:

ioctl in interface I2CDevice

Throws:

IOException

See Also:

LinuxFile.ioctl(long, int)

ioctl

public void ioctl(long command,
                  ByteBuffer data,
                  IntBuffer offsets)
           throws IOException

Description copied from interface: I2CDevice

Runs an ioctl on this device.

Specified by:

ioctl in interface I2CDevice

Throws:

IOException

See Also:

LinuxFile.ioctl(long, ByteBuffer, IntBuffer)

read

public int read(byte[] writeData,
                int writeOffset,
                int writeSize,
                byte[] readData,
                int readOffset,
                int readSize)
         throws IOException

This method writes and reads bytes to/from the i2c device in a single method call

Specified by:

read in interface I2CDevice

Parameters:

writeData - buffer of data to be written to the i2c device in one go

writeOffset - offset in write buffer

writeSize - number of bytes to be written from buffer

readData - buffer of data to be read from the i2c device in one go

readOffset - offset in read buffer

readSize - number of bytes to be read

Returns:

number of bytes read

Throws:

IOException - thrown in case byte cannot be read from the i2c device or i2c bus

makeDescription

protected String makeDescription()

This helper method creates a string describing bus file name and device address (in hex).

Returns:

string with all details

makeDescription

protected String makeDescription(int address)

This helper method creates a string describing bus file name, device address (in hex) and local i2c address.

Parameters:

address - local address in i2c device

Returns:

string with all details