frc::I2C Class Reference

I2C bus interface class. More...

#include <frc/I2C.h>

Public Types
enum	Port { kOnboard = 0 , kMXP }
	I2C connection ports. More...

Public Member Functions
	I2C (Port port, int deviceAddress)
	Constructor. More...
	~I2C ()
	I2C (I2C &&)=default
I2C &	operator= (I2C &&)=default
Port	GetPort () const
	Returns I2C port. More...
int	GetDeviceAddress () const
	Returns I2C device address. More...
bool	Transaction (uint8_t *dataToSend, int sendSize, uint8_t *dataReceived, int receiveSize)
	Generic transaction. More...
bool	AddressOnly ()
	Attempt to address a device on the I2C bus. More...
bool	Write (int registerAddress, uint8_t data)
	Execute a write transaction with the device. More...
bool	WriteBulk (uint8_t *data, int count)
	Execute a bulk write transaction with the device. More...
bool	Read (int registerAddress, int count, uint8_t *data)
	Execute a read transaction with the device. More...
bool	ReadOnly (int count, uint8_t *buffer)
	Execute a read only transaction with the device. More...
bool	VerifySensor (int registerAddress, int count, const uint8_t *expected)
	Verify that a device's registers contain expected values. More...

Detailed Description

I2C bus interface class.

This class is intended to be used by sensor (and other I2C device) drivers. It probably should not be used directly.

The Onboard I2C port is subject to system lockups. See WPILib Known Issues page for details.

Member Enumeration Documentation

Port

enum frc::I2C::Port

I2C connection ports.

Enumerator
kOnboard	Onboard I2C port.
kMXP	MXP (roboRIO MXP) I2C port.

Constructor & Destructor Documentation

I2C() [1/2]

frc::I2C::I2C	(	Port	port,
		int	deviceAddress
	)

Constructor.

Parameters

port	The I2C port to which the device is connected.
deviceAddress	The address of the device on the I2C bus.

~I2C()

frc::I2C::~I2C

(

)

I2C() [2/2]

frc::I2C::I2C ( I2C &&  )

default

Member Function Documentation

AddressOnly()

bool frc::I2C::AddressOnly

(

)

Attempt to address a device on the I2C bus.

This allows you to figure out if there is a device on the I2C bus that responds to the address specified in the constructor.

Returns

Transfer Aborted... false for success, true for aborted.

GetDeviceAddress()

int frc::I2C::GetDeviceAddress

(

)

const

Returns I2C device address.

Returns

I2C device address.

GetPort()

Port frc::I2C::GetPort

(

)

const

Returns I2C port.

Returns

I2C port.

operator=()

I2C & frc::I2C::operator= ( I2C &&  )

default

Read()

bool frc::I2C::Read	(	int	registerAddress,
		int	count,
		uint8_t *	data
	)

Execute a read transaction with the device.

Read bytes from a device. Most I2C devices will auto-increment the register pointer internally allowing you to read consecutive registers on a device in a single transaction.

Parameters

registerAddress	The register to read first in the transaction.
count	The number of bytes to read in the transaction.
data	A pointer to the array of bytes to store the data read from the device.

Returns

Transfer Aborted... false for success, true for aborted.

ReadOnly()

bool frc::I2C::ReadOnly	(	int	count,
		uint8_t *	buffer
	)

Execute a read only transaction with the device.

Read bytes from a device. This method does not write any data to prompt the device.

Parameters

buffer	A pointer to the array of bytes to store the data read from the device.
count	The number of bytes to read in the transaction.

Returns

Transfer Aborted... false for success, true for aborted.

Transaction()

bool frc::I2C::Transaction	(	uint8_t *	dataToSend,
		int	sendSize,
		uint8_t *	dataReceived,
		int	receiveSize
	)

Generic transaction.

This is a lower-level interface to the I2C hardware giving you more control over each transaction. If you intend to write multiple bytes in the same transaction and do not plan to receive anything back, use writeBulk() instead. Calling this with a receiveSize of 0 will result in an error.

Parameters

dataToSend	Buffer of data to send as part of the transaction.
sendSize	Number of bytes to send as part of the transaction.
dataReceived	Buffer to read data into.
receiveSize	Number of bytes to read from the device.

Returns

Transfer Aborted... false for success, true for aborted.

VerifySensor()

bool frc::I2C::VerifySensor	(	int	registerAddress,
		int	count,
		const uint8_t *	expected
	)

Verify that a device's registers contain expected values.

Most devices will have a set of registers that contain a known value that can be used to identify them. This allows an I2C device driver to easily verify that the device contains the expected value.

Precondition

The device must support and be configured to use register auto-increment.

Parameters

registerAddress	The base register to start reading from the device.
count	The size of the field to be verified.
expected	A buffer containing the values expected from the device.

Write()

bool frc::I2C::Write	(	int	registerAddress,
		uint8_t	data
	)

Execute a write transaction with the device.

Write a single byte to a register on a device and wait until the transaction is complete.

Parameters

registerAddress	The address of the register on the device to be written.
data	The byte to write to the register on the device.

Returns

Transfer Aborted... false for success, true for aborted.

WriteBulk()

bool frc::I2C::WriteBulk	(	uint8_t *	data,
		int	count
	)

Execute a bulk write transaction with the device.

Write multiple bytes to a device and wait until the transaction is complete.

Parameters

data	The data to write to the register on the device.
count	The number of bytes to be written.

Returns

Transfer Aborted... false for success, true for aborted.

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The documentation for this class was generated from the following file:

• frc/I2C.h