TWIBus Class Reference

#include <twibus.h>

Collaboration diagram for TWIBus:

Public Member Functions
	TWIBus ()
	Class constructor. More...
void	reset ()
	Reset the buffer. More...
void	send ()
	Send the buffer data to the bus. More...
void	addbyte (const char c)
	Add one byte to the buffer. More...
void	addbytes (char src[], uint8_t bytes)
	Add some bytes to the buffer. More...
void	addstring (char str[])
	Add a null-terminated string to the buffer. More...
void	address (const uint8_t adr)
	Set the target slave address. More...
void	echobuffer (const char prefix[], uint8_t adr)
	Echo data in the buffer to serial. More...
bool	request (const uint8_t bytes)
	Request data from the slave device and wait. More...
uint8_t	capture (char *dst, const uint8_t bytes)
	Capture data from the bus into the buffer. More...
void	relay (const uint8_t bytes)
	Request data from the slave device, echo to serial. More...

Static Public Member Functions
static void	echoprefix (uint8_t bytes, const char prefix[], uint8_t adr)
	Prefix for echo to serial. More...
static void	echodata (uint8_t bytes, const char prefix[], uint8_t adr)
	Echo data on the bus to serial. More...
static void	flush ()
	Flush the i2c bus. More...

Public Attributes
uint8_t	addr = 0
	Target device address @description The target device address. Persists until changed. More...

Detailed Description

TWIBUS class

This class implements a wrapper around the two wire (I2C) bus, allowing Marlin to send and request data from any slave device on the bus.

The two main consumers of this class are M260 and M261. M260 provides a way to send an I2C packet to a device (no repeated starts) by caching up to 32 bytes in a buffer and then sending the buffer. M261 requests data from a device. The received data is relayed to serial out for the host to interpret.

For more information see

• http://marlinfw.org/docs/gcode/M260.html
• http://marlinfw.org/docs/gcode/M261.html

Constructor & Destructor Documentation

TWIBus()

TWIBus::TWIBus

(

)

Class constructor.

Initialize the TWI bus and clear the buffer

Member Function Documentation

reset()

void TWIBus::reset

(

)

Reset the buffer.

Set the buffer to a known-empty state

send()

void TWIBus::send

(

)

Send the buffer data to the bus.

Flush the buffer to the target address

addbyte()

void TWIBus::addbyte

(

const char

c

)

Add one byte to the buffer.

Add a byte to the end of the buffer. Silently fails if the buffer is full.

Parameters

c	a data byte

addbytes()

void TWIBus::addbytes	(	char	src[],
		uint8_t	bytes
	)

Add some bytes to the buffer.

Add bytes to the end of the buffer. Concatenates at the buffer size.

Parameters

src	source data address
bytes	the number of bytes to add

addstring()

void TWIBus::addstring

(

char

str[]

)

Add a null-terminated string to the buffer.

Add bytes to the end of the buffer up to a nul. Concatenates at the buffer size.

Parameters

str	source string address

address()

void TWIBus::address

(

const uint8_t

adr

)

Set the target slave address.

The target slave address for sending the full packet

Parameters

adr	7-bit integer address

echoprefix()

static void TWIBus::echoprefix ( uint8_t  bytes, const char  prefix[], uint8_t  adr  )

static

Prefix for echo to serial.

Echo a label, length, address, and "data:"

Parameters

bytes

the number of bytes to request

echodata()

static void TWIBus::echodata ( uint8_t  bytes, const char  prefix[], uint8_t  adr  )

static

Echo data on the bus to serial.

Echo some number of bytes from the bus to serial in a parser-friendly format.

Parameters

bytes

the number of bytes to request

echobuffer()

void TWIBus::echobuffer	(	const char	prefix[],
		uint8_t	adr
	)

Echo data in the buffer to serial.

Echo the entire buffer to serial to serial in a parser-friendly format.

Parameters

bytes

the number of bytes to request

request()

bool TWIBus::request

(

const uint8_t

bytes

)

Request data from the slave device and wait.

Request a number of bytes from a slave device. Wait for the data to arrive, and return true on success.

Parameters

bytes

the number of bytes to request

Returns

status of the request: true=success, false=fail

capture()

uint8_t TWIBus::capture	(	char *	dst,
		const uint8_t	bytes
	)

Capture data from the bus into the buffer.

Capture data after a request has succeeded.

Parameters

bytes

the number of bytes to request

Returns

the number of bytes captured to the buffer

flush()

static void TWIBus::flush ( )

static

Flush the i2c bus.

Get all bytes on the bus and throw them away.

relay()

void TWIBus::relay

(

const uint8_t

bytes

)

Request data from the slave device, echo to serial.

Request a number of bytes from a slave device and output the returned data to serial in a parser-friendly format.

Parameters

bytes

the number of bytes to request

Member Data Documentation

addr

uint8_t TWIBus::addr = 0

Target device address @description The target device address. Persists until changed.