mrpt::hwdrivers::CInterfaceFTDI Class Reference

---

Detailed Description

A definition of a CStream actually representing a USB connection to a FTDI chip.

This class implements the communication with FT245BM / FT245RL chips. Using this class makes a program to depend on:

• Windows: "FT2XX.DLL" and the device drivers (see FTDI website).
• Linux: "libusb.so" (quite standard!), and "libftdi.so" only if linking against the dynamic library.

If there is any error during the communications (or loading the Windows DLL), a std::exception will be raised.

To write bulk data, use CStream::ReadBuffer and CStream::WriteBuffer. See also the derived classes for higher level communication: CInterfaceFTDIMessages

Warning: Avoid defining an object of this class in a global scope if you want to catch all potential exceptions during the constructors (like DLL not found, etc...)

VERSIONS:

• 11/APR/2005: Initial development. JLBC
• 16/FEB/2007: Integration into the MRPT framework. Support for device serial numbers. JLBC
• 15/APR/2008: Implemented for Linux using libftdi. JLBC

See also:

CInterfaceFTDIMessages, CStream

#include <mrpt/hwdrivers/CInterfaceFTDI.h>

Inheritance diagram for mrpt::hwdrivers::CInterfaceFTDI:

List of all members.

Public Types
enum	TSeekOrigin { sFromBeginning = 0, sFromCurrent = 1, sFromEnd = 2 }
	Used in CStream::Seek. More...
Public Member Functions
	CInterfaceFTDI ()
	Constructor, which loads driver interface (the DLL under Windows).
virtual	~CInterfaceFTDI ()
	Destructor, which closes the connection with the chip and unloads the driver interface.
	CInterfaceFTDI (const CInterfaceFTDI &o)
	This object cannot be copied.
CInterfaceFTDI &	operator= (const CInterfaceFTDI &o)
	This object cannot be copied.
bool	isOpen ()
	Checks whether the chip has been successfully open.
void	OpenBySerialNumber (const std::string &serialNumber)
	Open by device serial number.
void	OpenByDescription (const std::string &description)
	Open by device description.
void	Close ()
	Close the USB device.
void	ResetDevice ()
	Reset the USB device.
void	Purge ()
	Purge the I/O buffers.
void	SetLatencyTimer (unsigned char latency_ms)
	Change the latency timer (in milliseconds) implemented on the FTDI chip: for a few ms, data is not sent to the PC waiting for possible more data, to save USB trafic.
void	SetTimeouts (unsigned long dwReadTimeout_ms, unsigned long dwWriteTimeout_ms)
	Change read & write timeouts, in milliseconds.
void	ListAllDevices (TFTDIDeviceList &outList)
	Generates a list with all FTDI devices connected right now.
size_t	ReadSync (void *Buffer, size_t Count)
	Tries to read, raising no exception if not all the bytes are available, but raising one if there is some communication error.
size_t	WriteSync (const void *Buffer, size_t Count)
	Tries to write, raising no exception if not all the bytes are available, but raising one if there is some communication error.
virtual size_t	ReadBufferImmediate (void *Buffer, size_t Count)
	Reads a block of bytes from the stream into Buffer, and returns the amound of bytes actually read, without waiting for more extra bytes to arrive (just those already enqued in the stream).
size_t	ReadBuffer (void *Buffer, size_t Count)
	Reads a block of bytes from the stream into Buffer Exceptions: std::exception On any error, or if ZERO bytes are read.
template<typename T >
size_t	ReadBufferFixEndianness (T *ptr, size_t ElementCount)
	Reads a sequence of elemental datatypes, taking care of reordering their bytes from the MRPT stream standard (little endianness) to the format of the running architecture.
void	WriteBuffer (const void *Buffer, size_t Count)
	Writes a block of bytes to the stream from Buffer.
template<typename T >
void	WriteBufferFixEndianness (const T *ptr, size_t ElementCount)
	Writes a sequence of elemental datatypes, taking care of reordering their bytes from the running architecture to MRPT stream standard (little endianness).
size_t	CopyFrom (CStream *Source, size_t Count)
	Copies a specified number of bytes from one stream to another.
void	WriteObject (const CSerializable *o)
	Writes an object to the stream.
CSerializablePtr	ReadObject ()
	Reads an object from stream, its class determined at runtime, and returns a smart pointer to the object.
void	ReadObject (CSerializable *existingObj)
	Reads an object from stream, where its class must be the same as the supplied object, where the loaded object will be stored in.
CStream &	operator<< (const CSerializablePtr &pObj)
	Write an object to a stream in the binary MRPT format.
CStream &	operator<< (const CSerializable &obj)
	Write an object to a stream in the binary MRPT format.
CStream &	operator>> (CSerializablePtr &pObj)
CStream &	operator>> (CSerializable &obj)
virtual int	printf (const char *fmt,...) MRPT_printf_format_check(2
	Writes a string to the stream in a textual form.
template<typename T >
virtual int void	printf_vector (const char *fmt, const std::vector< T > &V)
	Prints a vector in the format [A,B,C,...] using CStream::printf, and the fmt string for each vector element.
void	sendMessage (const utils::CMessage &msg)
	Send a message to the device.
bool	receiveMessage (utils::CMessage &msg)
	Tries to receive a message from the device.
bool	getline (std::string &out_str)
	Reads from the stream until a ' ' character is found ('' characters are ignored).
Protected Member Functions
size_t	Read (void *Buffer, size_t Count)
	Introduces a pure virtual method responsible for reading from the stream.
size_t	Write (const void *Buffer, size_t Count)
	Introduces a pure virtual method responsible for writing to the stream.
uint64_t	Seek (long Offset, CStream::TSeekOrigin Origin=sFromBeginning)
	This virtual method does nothing in this class.
uint64_t	getTotalBytesCount ()
	This virtual method does nothing in this class.
uint64_t	getPosition ()
	This virtual method does nothing in this class.
void	ftdi_read (void *lpvBuffer, unsigned long dwBuffSize, unsigned long *lpdwBytesRead)
void	ftdi_write (const void *lpvBuffer, unsigned long dwBuffSize, unsigned long *lpdwBytes)
void	recursive_fill_list_devices (void *usb_device_structure, TFTDIDeviceList &outList)
	Process recursively a USB device and its children:
Protected Attributes
mrpt::utils::circular_buffer < uint8_t >	m_readBuffer
	Used in Read.
void *	m_ftdi_context

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Member Enumeration Documentation

enum mrpt::utils::CStream::TSeekOrigin [inherited]

Used in CStream::Seek.

Enumerator:

sFromBeginning
sFromCurrent
sFromEnd

Definition at line 60 of file CStream.h.

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Constructor & Destructor Documentation

mrpt::hwdrivers::CInterfaceFTDI::CInterfaceFTDI

(

)

Constructor, which loads driver interface (the DLL under Windows).

virtual mrpt::hwdrivers::CInterfaceFTDI::~CInterfaceFTDI

(

)

[virtual]

Destructor, which closes the connection with the chip and unloads the driver interface.

mrpt::hwdrivers::CInterfaceFTDI::CInterfaceFTDI

(

const CInterfaceFTDI &

o

)

This object cannot be copied.

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Member Function Documentation

void mrpt::hwdrivers::CInterfaceFTDI::Close

(

)

Close the USB device.

size_t mrpt::utils::CStream::CopyFrom	(	CStream *	Source,
		size_t	Count
	)		[inherited]

Copies a specified number of bytes from one stream to another.

void mrpt::hwdrivers::CInterfaceFTDI::ftdi_read	(	void *	lpvBuffer,
		unsigned long	dwBuffSize,
		unsigned long *	lpdwBytesRead
	)		[protected]

void mrpt::hwdrivers::CInterfaceFTDI::ftdi_write	(	const void *	lpvBuffer,
		unsigned long	dwBuffSize,
		unsigned long *	lpdwBytes
	)		[protected]

bool mrpt::utils::CStream::getline

(

std::string &

out_str

)

[inherited]

Reads from the stream until a '
' character is found ('' characters are ignored).

Returns:

false on EOF or any other read error.

uint64_t mrpt::hwdrivers::CInterfaceFTDI::getPosition

(

)

[protected, virtual]

This virtual method does nothing in this class.

Implements mrpt::utils::CStream.

uint64_t mrpt::hwdrivers::CInterfaceFTDI::getTotalBytesCount

(

)

[protected, virtual]

This virtual method does nothing in this class.

Implements mrpt::utils::CStream.

bool mrpt::hwdrivers::CInterfaceFTDI::isOpen

(

)

Checks whether the chip has been successfully open.

See also:

OpenBySerialNumber, OpenByDescription

void mrpt::hwdrivers::CInterfaceFTDI::ListAllDevices

(

TFTDIDeviceList &

outList

)

Generates a list with all FTDI devices connected right now.

void mrpt::hwdrivers::CInterfaceFTDI::OpenByDescription

(

const std::string &

description

)

Open by device description.

void mrpt::hwdrivers::CInterfaceFTDI::OpenBySerialNumber

(

const std::string &

serialNumber

)

Open by device serial number.

CStream& mrpt::utils::CStream::operator<<

(

const CSerializablePtr &

pObj

)

[inherited]

Write an object to a stream in the binary MRPT format.

CStream& mrpt::utils::CStream::operator<<

(

const CSerializable &

obj

)

[inherited]

Write an object to a stream in the binary MRPT format.

CInterfaceFTDI& mrpt::hwdrivers::CInterfaceFTDI::operator=

(

const CInterfaceFTDI &

o

)

This object cannot be copied.

CStream& mrpt::utils::CStream::operator>>

(

CSerializablePtr &

pObj

)

[inherited]

CStream& mrpt::utils::CStream::operator>>

(

CSerializable &

obj

)

[inherited]

virtual int mrpt::utils::CStream::printf	(	const char *	fmt,
			...
	)		[virtual, inherited]

Writes a string to the stream in a textual form.

See also:

CStdOutStream

template<typename T >

virtual int void mrpt::utils::CStream::printf_vector	(	const char *	fmt,
		const std::vector< T > &	V
	)		[inline, inherited]

Prints a vector in the format [A,B,C,...] using CStream::printf, and the fmt string for each vector element.

Definition at line 219 of file CStream.h.

void mrpt::hwdrivers::CInterfaceFTDI::Purge

(

)

Purge the I/O buffers.

size_t mrpt::hwdrivers::CInterfaceFTDI::Read	(	void *	Buffer,
		size_t	Count
	)		[protected, virtual]

Introduces a pure virtual method responsible for reading from the stream.

It integrates a cache buffer to speed-up sequences of many, small readings.

Implements mrpt::utils::CStream.

size_t mrpt::utils::CStream::ReadBuffer	(	void *	Buffer,
		size_t	Count
	)		[inherited]

Reads a block of bytes from the stream into Buffer

Exceptions:

std::exception

On any error, or if ZERO bytes are read.

Returns:

The amound of bytes actually read.

Note:

This method is endianness-dependent.

See also:

ReadBufferImmediate ; Important, see: ReadBufferFixEndianness,

template<typename T >

size_t mrpt::utils::CStream::ReadBufferFixEndianness	(	T *	ptr,
		size_t	ElementCount
	)		[inline, inherited]

Reads a sequence of elemental datatypes, taking care of reordering their bytes from the MRPT stream standard (little endianness) to the format of the running architecture.

Parameters:

ElementCount	The number of elements (not bytes) to read.
ptr	A pointer to the first output element in an array (or std::vector<>, etc...).

Returns:

The amound of *bytes* (not elements) actually read (under error situations, the last element may be invalid if the data stream abruptly ends). Example of usage:

   uint32_t  N;
   s >> N;
   vector<float>  vec(N);
   if (N) 
     s.ReadBufferFixEndianness<float>(&vec[0],N);

Exceptions:

std::exception

On any error, or if ZERO bytes are read.

See also:

ReadBufferFixEndianness, ReadBuffer

Definition at line 109 of file CStream.h.

References mrpt::utils::reverseBytesInPlace().

Referenced by mrpt::math::operator>>().

virtual size_t mrpt::hwdrivers::CInterfaceFTDI::ReadBufferImmediate	(	void *	Buffer,
		size_t	Count
	)		[virtual]

Reads a block of bytes from the stream into Buffer, and returns the amound of bytes actually read, without waiting for more extra bytes to arrive (just those already enqued in the stream).

In this class this method actually behaves as expected and does not fallback to ReadBuffer().

Exceptions:

std::exception

On any error, or if ZERO bytes are read.

Reimplemented from mrpt::utils::CStream.

CSerializablePtr mrpt::utils::CStream::ReadObject

(

)

[inherited]

Reads an object from stream, its class determined at runtime, and returns a smart pointer to the object.

Exceptions:

std::exception	On I/O error or undefined class.
mrpt::utils::CExceptionEOF	On an End-Of-File condition found at a correct place: an EOF that abruptly finishes in the middle of one object raises a plain std::exception instead.

Referenced by mrpt::math::operator>>().

void mrpt::utils::CStream::ReadObject

(

CSerializable *

existingObj

)

[inherited]

Reads an object from stream, where its class must be the same as the supplied object, where the loaded object will be stored in.

Exceptions:

std::exception	On I/O error or different class found.
mrpt::utils::CExceptionEOF	On an End-Of-File condition found at a correct place: an EOF that abruptly finishes in the middle of one object raises a plain std::exception instead.

size_t mrpt::hwdrivers::CInterfaceFTDI::ReadSync	(	void *	Buffer,
		size_t	Count
	)		[inline]

Tries to read, raising no exception if not all the bytes are available, but raising one if there is some communication error.

Definition at line 144 of file CInterfaceFTDI.h.

bool mrpt::utils::CStream::receiveMessage

(

utils::CMessage &

msg

)

[inherited]

Tries to receive a message from the device.

Exceptions:

std::exception

On communication errors

Returns:

True if successful, false if there is no new data from the device (but communications seem to work fine)

See also:

The frame format is described in sendMessage()

void mrpt::hwdrivers::CInterfaceFTDI::recursive_fill_list_devices	(	void *	usb_device_structure,
		TFTDIDeviceList &	outList
	)		[protected]

Process recursively a USB device and its children:

void mrpt::hwdrivers::CInterfaceFTDI::ResetDevice

(

)

Reset the USB device.

uint64_t mrpt::hwdrivers::CInterfaceFTDI::Seek	(	long	Offset,
		CStream::TSeekOrigin	Origin = sFromBeginning
	)		[protected, virtual]

This virtual method does nothing in this class.

Implements mrpt::utils::CStream.

void mrpt::utils::CStream::sendMessage

(

const utils::CMessage &

msg

)

[inherited]

Send a message to the device.

Note that only the low byte from the "type" field will be used.

For frames of size < 255 the frame format is an array of bytes in this order:

  <START_FLAG> <HEADER> <LENGTH> <BODY> <END_FLAG>
        <START_FLAG>    = 0x69
        <HEADER>                = A header byte
        <LENGHT>                = Number of bytes of BODY
        <BODY>                  = N x bytes
        <END_FLAG>              = 0X96
  Total length  =       <LENGTH> + 4

For frames of size > 255 the frame format is an array of bytes in this order:

  <START_FLAG> <HEADER> <HIBYTE(LENGTH)> <LOBYTE(LENGTH)> <BODY> <END_FLAG>
        <START_FLAG>    = 0x79
        <HEADER>                = A header byte
        <LENGHT>                = Number of bytes of BODY
        <BODY>                  = N x bytes
        <END_FLAG>              = 0X96
  Total length  =       <LENGTH> + 5

Exceptions:

std::exception

On communication errors

void mrpt::hwdrivers::CInterfaceFTDI::SetLatencyTimer

(

unsigned char

latency_ms

)

Change the latency timer (in milliseconds) implemented on the FTDI chip: for a few ms, data is not sent to the PC waiting for possible more data, to save USB trafic.

void mrpt::hwdrivers::CInterfaceFTDI::SetTimeouts	(	unsigned long	dwReadTimeout_ms,
		unsigned long	dwWriteTimeout_ms
	)

Change read & write timeouts, in milliseconds.

size_t mrpt::hwdrivers::CInterfaceFTDI::Write	(	const void *	Buffer,
		size_t	Count
	)		[protected, virtual]

Introduces a pure virtual method responsible for writing to the stream.

Write attempts to write up to Count bytes to Buffer, and returns the number of bytes actually written.

Implements mrpt::utils::CStream.

void mrpt::utils::CStream::WriteBuffer	(	const void *	Buffer,
		size_t	Count
	)		[inherited]

Writes a block of bytes to the stream from Buffer.

Exceptions:

std::exception

On any error

See also:

Important, see: WriteBufferFixEndianness

Note:

This method is endianness-dependent.

template<typename T >

void mrpt::utils::CStream::WriteBufferFixEndianness	(	const T *	ptr,
		size_t	ElementCount
	)		[inline, inherited]

Writes a sequence of elemental datatypes, taking care of reordering their bytes from the running architecture to MRPT stream standard (little endianness).

Parameters:

ElementCount	The number of elements (not bytes) to write.
ptr	A pointer to the first input element in an array (or std::vector<>, etc...). Example of usage: vector<float> vec = ... uint32_t N = vec.size(); s << N if (N) s.WriteBufferFixEndianness<float>(&vec[0],N);

Exceptions:

std::exception

On any error

See also:

WriteBuffer

Definition at line 153 of file CStream.h.

void mrpt::utils::CStream::WriteObject

(

const CSerializable *

o

)

[inherited]

Writes an object to the stream.

size_t mrpt::hwdrivers::CInterfaceFTDI::WriteSync	(	const void *	Buffer,
		size_t	Count
	)		[inline]

Tries to write, raising no exception if not all the bytes are available, but raising one if there is some communication error.

Definition at line 151 of file CInterfaceFTDI.h.

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Member Data Documentation

void* mrpt::hwdrivers::CInterfaceFTDI::m_ftdi_context [protected]

Definition at line 245 of file CInterfaceFTDI.h.

mrpt::utils::circular_buffer<uint8_t> mrpt::hwdrivers::CInterfaceFTDI::m_readBuffer [protected]

Used in Read.

Definition at line 168 of file CInterfaceFTDI.h.