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I2C Class Reference

I2C Class Reference

An I2C Master, used for communicating with I2C slave devices. More...

#include <I2C.h>

Public Member Functions

 I2C (PinName sda, PinName scl)
 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 read (int ack)
 Read a single byte from the I2C bus.
int write (int address, const char *data, int length, bool repeated=false)
 Write to an I2C slave.
int write (int data)
 Write single byte out on the I2C bus.
void start (void)
 Creates a start condition on the I2C bus.
void stop (void)
 Creates a stop condition on the I2C bus.
int transfer (int address, const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length, const event_callback_t &callback, int event=I2C_EVENT_TRANSFER_COMPLETE, bool repeated=false)
 Start non-blocking I2C transfer.
void abort_transfer ()
 Abort the on-going I2C transfer.

Detailed Description

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);
 }

Definition at line 50 of file I2C.h.


Constructor & Destructor Documentation

I2C ( PinName  sda,
PinName  scl 
)

Create an I2C Master interface, connected to the specified pins.

Parameters:
sdaI2C data line pin
sclI2C clock line pin

Member Function Documentation

void abort_transfer (  )

Abort the on-going I2C transfer.

void frequency ( int  hz )

Set the frequency of the I2C interface.

Parameters:
hzThe bus frequency in hertz
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.

Parameters:
address8-bit I2C slave address [ addr | 1 ]
dataPointer to the byte-array to read data in to
lengthNumber of bytes to read
repeatedRepeated start, true - don't send stop at end
Returns:
0 on success (ack), non-0 on failure (nack)
int read ( int  ack )

Read a single byte from the I2C bus.

Parameters:
ackindicates if the byte is to be acknowledged (1 = acknowledge)
Returns:
the byte read
void start ( void   )

Creates a start condition on the I2C bus.

void stop ( void   )

Creates a stop condition on the I2C bus.

int transfer ( int  address,
const char *  tx_buffer,
int  tx_length,
char *  rx_buffer,
int  rx_length,
const event_callback_t callback,
int  event = I2C_EVENT_TRANSFER_COMPLETE,
bool  repeated = false 
)

Start non-blocking I2C transfer.

Parameters:
address8/10 bit I2c slave address
tx_bufferThe TX buffer with data to be transfered
tx_lengthThe length of TX buffer in bytes
rx_bufferThe RX buffer which is used for received data
rx_lengthThe length of RX buffer in bytes
eventThe logical OR of events to modify
callbackThe event callback function
repeatedRepeated start, true - do not send stop at end
Returns:
Zero if the transfer has started, or -1 if I2C peripheral is busy
int write ( int  data )

Write single byte out on the I2C bus.

Parameters:
datadata to write out on bus
Returns:
'1' if an ACK was received, '0' otherwise
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.

Parameters:
address8-bit I2C slave address [ addr | 0 ]
dataPointer to the byte-array data to send
lengthNumber of bytes to send
repeatedRepeated start, true - do not send stop at end
Returns:
0 on success (ack), non-0 on failure (nack)