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api / mbed / trunk / I2C

I2C

class I2C : public Base

An I2C Master, used for communicating with I2C slave devices

Example

// Read from I2C slave at address 0x62

#include "mbed.h"

I2C i2c(p28, p27);

int main() {
    int address = 0x62;
    char data[2];
    i2c.read(address, data, 2);
}

I2C	An I2C Master, used for communicating with I2C slave devices
Functions
I2C	Create an I2C Master interface, connected to the specified pins
frequency	Set the frequency of the I2C interface
read	Read from an I2C slave
read	Read a single byte from the I2C bus
write	Write to an I2C slave
write	Write single byte out on the I2C bus
start	Creates a start condition on the I2C bus
stop	Creates a stop condition on the I2C bus

Functions

I2C

I2C( PinName sda,
PinName scl,
const char * name = NULL )

Create an I2C Master interface, connected to the specified pins

Variables

sda	I2C data line pin
scl	I2C clock line pin

frequency

void frequency( int hz )

Set the frequency of the I2C interface

Variables

hz	The bus frequency in hertz

read

int read( int address,
char * data,
int length,
bool repeated = false )

Read from an I2C slave

Performs a complete read transaction. The bottom bit of the address is forced to 1 to indicate a read.

Variables

address	8-bit I2C slave address [ addr \| 1 ]
data	Pointer to the byte-array to read data in to
length	Number of bytes to read
repeated	Repeated start, true - don’t send stop at end
returns	0 on success (ack), or non-0 on failure (nack)

read

int read( int ack )

Read a single byte from the I2C bus

Variables

ack	indicates if the byte is to be acknowledged (1 = acknowledge)
returns	the byte read

write

int write( int address,
const char * data,
int length,
bool repeated = false )

Write to an I2C slave

Performs a complete write transaction. The bottom bit of the address is forced to 0 to indicate a write.

Variables

address	8-bit I2C slave address [ addr \| 0 ]
data	Pointer to the byte-array data to send
length	Number of bytes to send
repeated	Repeated start, true - do not send stop at end
returns	0 on success (ack), or non-0 on failure (nack)

write

int write( int data )

Write single byte out on the I2C bus

Variables

data	data to write out on bus
returns	a ‘1’ if an ACK was received, a ‘0’ otherwise

start

void start( void )

Creates a start condition on the I2C bus

stop

void stop( void )

Creates a stop condition on the I2C bus

class I2C : public Base

An I2C Master, used for communicating with I2C slave devices

I2C( PinName sda,
PinName scl,
const char * name = NULL )

Create an I2C Master interface, connected to the specified pins

void frequency( int hz )

Set the frequency of the I2C interface

int read( int address,
char * data,
int length,
bool repeated = false )

Read from an I2C slave

int write( int address,
const char * data,
int length,
bool repeated = false )

Write to an I2C slave

void start( void )

Creates a start condition on the I2C bus

void stop( void )

Creates a stop condition on the I2C bus