An I2C Slave, used for communicating with an I2C Master device. More...

#include <I2CSlave.h>

Inheritance diagram for I2CSlave:

Public Member Functions
	I2CSlave (PinName sda, PinName scl)
	Create an I2C Slave interface, connected to the specified pins. More...

void	frequency (int hz)
	Set the frequency of the I2C interface. More...

void	timeout (uint32_t timeout)
	Configure the timeout duration in microseconds for blocking transmission. More...

int	receive (void)
	Check if this I2C Slave has been addressed. More...

int	read (char *data, int length)
	Read specified number of bytes from an I2C master. More...

int	read (void)
	Read a single byte from an I2C master. More...

int	write (const char *data, int length)
	Write to an I2C master. More...

int	write (int data)
	Write a single byte to an I2C master. More...

void	address (int address)
	Set the I2C slave address. More...

void	stop (void)
	Reset the I2C slave back into the known ready receiving state. More...

Detailed Description

An I2C Slave, used for communicating with an I2C Master device.

Note: Synchronization level: Not protected

Example Simple I2C responder:

#include <mbed.h>
const int SLAVE_ADDRESS = 0xA0;
const char message[] = "Slave!";
I2CSlave slave(I2C_SDA, I2C_SCL);
int main() {
    slave.address(SLAVE_ADDRESS);
    while (1) {
        int operation = slave.receive();
        switch (operation) {
            case I2CSlave::ReadAddressed:
                int status = slave.write(message, sizeof(message));
                if (status == 0) {
                    printf("Written message: %s\n", message);
                } else {
                    printf("Failed to write message.\n");
                }
                break;
            case I2CSlave::WriteGeneral:
                int byte_read = slave.read();
                printf("Read General: %c (%d)\n", byte_read, byte_read);
                break;
            case I2CSlave::WriteAddressed:
                int byte_read = slave.read();
                printf("Read Addressed: %c (%d)\n", byte_read, byte_read);
                break;
        }
    }
}

Definition at line 73 of file I2CSlave.h.

Constructor & Destructor Documentation

I2CSlave	(	PinName	sda,
		PinName	scl
	)

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

Parameters

sda	I2C data line pin.
scl	I2C clock line pin.

Member Function Documentation

void address ( int address )

Set the I2C slave address.

Parameters

address The address to set for the slave (least significant bit is ignored).

Note: If address is set to 0, the slave will only respond to the general call address.

void frequency ( int hz )

Set the frequency of the I2C interface.

Parameters

hz	The bus frequency in Hertz.

int read	(	char *	data,
		int	length
	)

Read specified number of bytes from an I2C master.

Parameters

data	Pointer to the buffer to read data into.
length	Number of bytes to read.

Returns: Result of the operation.

Return values

0	If the number of bytes read is equal to length requested.
nonzero	On error or if the number of bytes read is less than requested.

int read ( void )

Read a single byte from an I2C master.

Returns: The byte read.

int receive ( void )

Check if this I2C Slave has been addressed.

Returns: A status indicating if the device has been addressed and how.

Return values

NoData	The slave has not been addressed.
ReadAddressed	The master has requested a read from this slave.
WriteAddressed	The master is writing to this slave.
WriteGeneral	The master is writing to all slave.

void stop ( void )

Reset the I2C slave back into the known ready receiving state.

void timeout ( uint32_t timeout )

Configure the timeout duration in microseconds for blocking transmission.

Parameters

timeout Transmission timeout in microseconds.

Note: If no timeout is set the default timeout is used. Default timeout value is based on I2C frequency. Byte timeout is computed as triple amount of time it would take to send 10bit over I2C and is expressed by the formula: byte_timeout = 3 * (1/frequency * 10 * 1000000)

int write	(	const char *	data,
		int	length
	)

Write to an I2C master.

Parameters

data	Pointer to the buffer containing the data to be sent.
length	Number of bytes to send.

Returns

Return values

0	If written all bytes successfully.
nonzero	On error or if the number of bytes written is less than requested.

int write ( int data )

Write a single byte to an I2C master.

Parameters

data	Value to write.

Returns: Result of the operation.

Return values

0	If a NACK is received.
1	If an ACK is received.
2	On timeout.

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

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