Two-Wire Interface

Functions
void	twi_set_ack (uint8_t ack)
void	twi_interrupt_config (uint8_t cmd)
void	twi_send_byte (uint8_t val)
void	twi_send_start (void)
void	twi_send_stop (void)
void	twi_set_prescalar (uint8_t pre)
void	twi_wait_twint (void)
uint8_t	twi_get_twint (void)
uint8_t	twi_get_status (void)
uint8_t	twi_get_byte (void)
void	twi_set_state (uint8_t val)
uint8_t	twi_get_state (void)
uint8_t	twi_get_stop (void)
void	twi_set_rate (uint8_t rate)
void	twi_set_address (uint8_t address)
void	twi_set_twint (void)

---

Function Documentation

uint8_t twi_get_byte

(

void

)

[inline]

Return the byte received from the twi transaction

Returns:

Last byte received.

Author:

Andrew H. Fagg

uint8_t twi_get_state

(

void

)

[inline]

Get the state of the TWCR register

Returns:

The state of the TWCR register.

Author:

Andrew H. Fagg

uint8_t twi_get_status

(

void

)

[inline]

Return the status register

Returns:

The value of the TWI status register.

Author:

Andrew H. Fagg

uint8_t twi_get_stop

(

void

)

[inline]

Get the stop state of the TWI device.

Returns:

The stop state: 0 or _BF(TWSTO)

Author:

Andrew H. Fagg

uint8_t twi_get_twint

(

void

)

[inline]

Return the TWINT status bit.

Returns:

0: not ready
non-zero (_BV(TWINT)): ready.

Author:

Andrew H. Fagg

void twi_interrupt_config

(

uint8_t

cmd

)

Configure the TWI interrupt.

Parameters:

cmd

TWI_INTERRUPT_ENABLE: enable the twi interrupt TWI_INTERRUPT_DISABLE: disable

Author:

Andrew H. Fagg

void twi_send_byte

(

uint8_t

val

)

Place a byte for transmission into the buffer.

Note: Initiates the transmission of the byte immediately.

Parameters:

val

Byte value to transmit

Author:

Andrew H. Fagg

void twi_send_start

(

void

)

Initiate the transmission of the "start" sequence

Note: initiates the transfer of this sequence.

Author:

Andrew H. Fagg

void twi_send_stop

(

void

)

Initiate the transfer of the the stop sequence

Note: Initiates the actual transfer immediately

Author:

Andrew H. Fagg

void twi_set_ack

(

uint8_t

ack

)

Set the state of the TWI acknowledgement.

Note: this does not initiate a transmission. A 2nd call is required to do this (e.g., twi_set_ack(), or twi_send_byte())

Parameters:

ack

TWI_ACKNOWLEDGE_ENABLE: acknowledge TWI_ACKNOWLEDGE_DISABLE: do not acknowledge

Author:

Andrew H. Fagg

Set the state of the acknowledgement bit.

Note: this does not initiate a transmission. A 2nd call is required to do this (e.g., twi_set_twint(), or twi_send_byte())

Parameters:

ack

TWI_ACKNOWLEDGE_ENABLE: acknowledge TWI_ACKNOWLEDGE_DISABLE: do not acknowledge

Author:

Andrew H. Fagg

void twi_set_address

(

uint8_t

address

)

[inline]

Set the slave address

Parameters:

address

Slave address

Author:

Andrew H. Fagg

void twi_set_prescalar

(

uint8_t

pre

)

Set the clock prescalar for the TWI device.

Parameters:

pre

One of: TWI_PRESCALAR_1: divide system clock by 1 TWI_PRESCALAR_4: divide by 4 TWI_PRESCALAR_16: divide by 16 TWI_PRESCALAR_64: divide by 64

Author:

Andrew H. Fagg

void twi_set_rate

(

uint8_t

rate

)

[inline]

Set the TWI data transmission rate

Parameters:

rate

Transmission rate

Author:

Andrew H. Fagg

void twi_set_state

(

uint8_t

val

)

[inline]

Set the state of the TWCR register

Parameters:

val

The value to set TWCR to.

Author:

Andrew H. Fagg

void twi_set_twint

(

void

)

[inline]

Force the twi device to initiate a transaction immediately. We assume that the device has already been configured

Author:

Andrew H. Fagg

void twi_wait_twint

(

void

)

Return when the twi device is ready to be serviced. This should only be used in non-interrupt mode.

Author:

Andrew H. Fagg