com.sun.spot.peripheral
Class AT91_I2C

java.lang.Object
  com.sun.spot.resources.Resource
      com.sun.spot.peripheral.AT91_I2C

All Implemented Interfaces:

II2C, IResource

public class AT91_I2C
extends Resource
implements II2C

Class for communicating with devices using the I2C protocol using the ARM9 TWI hardware. Uses the I2C_DATA and I2C_CLK pins in the top connector for SDA and SCK of the TWI interface.

Author:

Ron Goldman

Constructor Summary

AT91_I2C()

Method Summary

void	close() Release any resources associated with the I2C hardware.
boolean	isBusy() Check if an I2C data transfer is currently in process.
void	open() Initialize the I2C hardware.
boolean	probe(int slaveAddress, int probeData) Check if a slave device is present at the given address.
void	read(int slaveAddress, byte[] data, int off, int len) Read data from the specified I2C slave device.
void	read(int slaveAddress, int internalAddress, int internalAddressSize, byte[] data, int off, int len) Read data from the specified I2C slave device.
void	setClockSpeed(int clockSpeed) Set the clock speed to use for I2C data transfers.
void	write(int slaveAddress, byte[] data, int off, int len) Write data to the specified I2C slave device.
void	write(int slaveAddress, int internalAddress, int internalAddressSize, byte[] data, int off, int len) Write data to the specified I2C slave device.

Methods inherited from class com.sun.spot.resources.Resource

addTag, getTags, getTagValue, hasTag, removeTag

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.sun.spot.resources.IResource

addTag, getTags, getTagValue, hasTag, removeTag

Constructor Detail

AT91_I2C

public AT91_I2C()

Method Detail

open

public void open()
          throws IOException

Initialize the I2C hardware.

Specified by:

open in interface II2C

Throws:

IOException

close

public void close()
           throws IOException

Release any resources associated with the I2C hardware.

Specified by:

close in interface II2C

Throws:

IOException

setClockSpeed

public void setClockSpeed(int clockSpeed)

Set the clock speed to use for I2C data transfers. The initial clock speed is set to 100KHz.

Specified by:

setClockSpeed in interface II2C

Parameters:

clockSpeed - I2C bus clock in Hertz

write

public void write(int slaveAddress,
                  byte[] data,
                  int off,
                  int len)
           throws IOException

Write data to the specified I2C slave device.

Specified by:

write in interface II2C

Parameters:

slaveAddress - 7-bit slave address, shifted left one bit so LSB is not used

data - Array of bytes to write

off - Offset from which to start writing data

len - How many bytes of data to write

Throws:

IOException

write

public void write(int slaveAddress,
                  int internalAddress,
                  int internalAddressSize,
                  byte[] data,
                  int off,
                  int len)
           throws IOException

Write data to the specified I2C slave device.

Specified by:

write in interface II2C

Parameters:

slaveAddress - 7-bit slave address, shifted left one bit so LSB is not used

internalAddress - 0-3 bytes of internal address information sent to the slave device before any data.

internalAddressSize - how many bytes of internal address information are to be sent

data - Array of bytes to write

off - Offset from which to start writing data

len - How many bytes of data to write

Throws:

IOException

read

public void read(int slaveAddress,
                 byte[] data,
                 int off,
                 int len)
          throws IOException

Read data from the specified I2C slave device.

Specified by:

read in interface II2C

Parameters:

slaveAddress - 7-bit slave address, shifted left one bit so LSB is not used

data - Array of bytes to read into

off - Offset from which to start reading data

len - How many bytes of data to read

Throws:

IOException

read

public void read(int slaveAddress,
                 int internalAddress,
                 int internalAddressSize,
                 byte[] data,
                 int off,
                 int len)
          throws IOException

Read data from the specified I2C slave device.

Specified by:

read in interface II2C

Parameters:

slaveAddress - 7-bit slave address, shifted left one bit so LSB is not used

internalAddress - 0-3 bytes of internal address information sent to the slave device before any data

internalAddressSize - how many bytes of internal address information are to be sent

data - Array of bytes to read into

off - Offset from which to start reading data

len - How many bytes of data to read

Throws:

IOException

isBusy

public boolean isBusy()

Check if an I2C data transfer is currently in process.

Specified by:

isBusy in interface II2C

Returns:

true if a data transfer is currently in process

probe

public boolean probe(int slaveAddress,
                     int probeData)

Check if a slave device is present at the given address. Tries to write a byte to the device and sees if it gets a NACK.

Specified by:

probe in interface II2C

Parameters:

slaveAddress - 7-bit slave address, shifted left one bit so LSB is not used

probeData - - byte value to try writing to device

Returns:

false if no device is present