TWI peripheral driver. More...

Modules
	TWI peripheral driver configuration

Data Structures
struct	nrfx_twi_t
	Structure for the TWI master driver instance. More...

struct	nrfx_twi_config_t
	Structure for the TWI master driver instance configuration. More...

struct	nrfx_twi_xfer_desc_t
	Structure for a TWI transfer descriptor. More...

struct	nrfx_twi_evt_t
	Structure for a TWI event. More...

Macros
#define	NRFX_TWI_INSTANCE(id)
	Macro for creating a TWI master driver instance. More...

#define	NRFX_TWI_DEFAULT_CONFIG
	TWI master driver instance default configuration. More...

#define	NRFX_TWI_FLAG_NO_XFER_EVT_HANDLER (1UL << 2)

#define	NRFX_TWI_FLAG_TX_NO_STOP (1UL << 5)

#define	NRFX_TWI_XFER_DESC_TX(addr, p_data, length)
	Macro for setting the TX transfer descriptor. More...

#define	NRFX_TWI_XFER_DESC_RX(addr, p_data, length)
	Macro for setting the RX transfer descriptor. More...

#define	NRFX_TWI_XFER_DESC_TXRX(addr, p_tx, tx_len, p_rx, rx_len)
	Macro for setting the TXRX transfer descriptor. More...

#define	NRFX_TWI_XFER_DESC_TXTX(addr, p_tx, tx_len, p_tx2, tx_len2)
	Macro for setting the TXTX transfer descriptor. More...

Typedefs
typedef void(*	nrfx_twi_evt_handler_t )(nrfx_twi_evt_t const p_event, void p_context)
	TWI event handler prototype.

Enumerations
enum	{ NRFX_TWI_ENABLED_COUNT }

enum	nrfx_twi_evt_type_t { NRFX_TWI_EVT_DONE, NRFX_TWI_EVT_ADDRESS_NACK, NRFX_TWI_EVT_DATA_NACK }
	TWI master driver event types. More...

enum	nrfx_twi_xfer_type_t { NRFX_TWI_XFER_TX, NRFX_TWI_XFER_RX, NRFX_TWI_XFER_TXRX, NRFX_TWI_XFER_TXTX }
	TWI master driver transfer types. More...

Functions
nrfx_err_t	nrfx_twi_init (nrfx_twi_t const p_instance, nrfx_twi_config_t const p_config, nrfx_twi_evt_handler_t event_handler, void *p_context)
	Function for initializing the TWI driver instance. More...

void	nrfx_twi_uninit (nrfx_twi_t const *p_instance)
	Function for uninitializing the TWI instance. More...

void	nrfx_twi_enable (nrfx_twi_t const *p_instance)
	Function for enabling the TWI instance. More...

void	nrfx_twi_disable (nrfx_twi_t const *p_instance)
	Function for disabling the TWI instance. More...

nrfx_err_t	nrfx_twi_tx (nrfx_twi_t const p_instance, uint8_t address, uint8_t const p_data, size_t length, bool no_stop)
	Function for sending data to a TWI slave. More...

nrfx_err_t	nrfx_twi_rx (nrfx_twi_t const p_instance, uint8_t address, uint8_t p_data, size_t length)
	Function for reading data from a TWI slave. More...

nrfx_err_t	nrfx_twi_xfer (nrfx_twi_t const p_instance, nrfx_twi_xfer_desc_t const p_xfer_desc, uint32_t flags)
	Function for preparing a TWI transfer. More...

bool	nrfx_twi_is_busy (nrfx_twi_t const *p_instance)
	Function for checking the TWI driver state. More...

size_t	nrfx_twi_data_count_get (nrfx_twi_t const *const p_instance)
	Function for getting the transferred data count. More...

uint32_t	nrfx_twi_stopped_event_get (nrfx_twi_t const *p_instance)
	Function for returning the address of a STOPPED TWI event. More...

void	nrfx_twi_0_irq_handler (void)

void	nrfx_twi_1_irq_handler (void)

Detailed Description

TWI peripheral driver.

Macro Definition Documentation

#define NRFX_TWI_DEFAULT_CONFIG

Value:

{ \
 .frequency = (nrf_twi_frequency_t)NRFX_TWI_DEFAULT_CONFIG_FREQUENCY, \
 .scl = 31, \
 .sda = 31, \
 .interrupt_priority = NRFX_TWI_DEFAULT_CONFIG_IRQ_PRIORITY, \
 .hold_bus_uninit = NRFX_TWI_DEFAULT_CONFIG_HOLD_BUS_UNINIT, \
}

TWI master driver instance default configuration.

#define NRFX_TWI_FLAG_NO_XFER_EVT_HANDLER (1UL << 2)

Interrupt after each transfer is suppressed, and the event handler is not called.

#define NRFX_TWI_FLAG_TX_NO_STOP (1UL << 5)

Flag indicating that the TX transfer will not end with a stop condition.

#define NRFX_TWI_INSTANCE ( id )

Value:

{ \
 .p_twi = NRFX_CONCAT_2(NRF_TWI, id), \
 .drv_inst_idx = NRFX_CONCAT_3(NRFX_TWI, id, _INST_IDX), \
}

Macro for creating a TWI master driver instance.

#define NRFX_TWI_XFER_DESC_RX	(	addr,
		p_data,
		length
	)

Value:

{ \
 .type = NRFX_TWI_XFER_RX, \
 .address = addr, \
 .primary_length = length, \
 .p_primary_buf = p_data, \
 }

Macro for setting the RX transfer descriptor.

#define NRFX_TWI_XFER_DESC_TX	(	addr,
		p_data,
		length
	)

Value:

{ \
 .type = NRFX_TWI_XFER_TX, \
 .address = addr, \
 .primary_length = length, \
 .p_primary_buf = p_data, \
 }

Macro for setting the TX transfer descriptor.

#define NRFX_TWI_XFER_DESC_TXRX	(	addr,
		p_tx,
		tx_len,
		p_rx,
		rx_len
	)

Value:

{ \
 .type = NRFX_TWI_XFER_TXRX, \
 .address = addr, \
 .primary_length = tx_len, \
 .secondary_length = rx_len, \
 .p_primary_buf = p_tx, \
 .p_secondary_buf = p_rx, \
 }

Macro for setting the TXRX transfer descriptor.

#define NRFX_TWI_XFER_DESC_TXTX	(	addr,
		p_tx,
		tx_len,
		p_tx2,
		tx_len2
	)

Value:

{ \
 .type = NRFX_TWI_XFER_TXTX, \
 .address = addr, \
 .primary_length = tx_len, \
 .secondary_length = tx_len2, \
 .p_primary_buf = p_tx, \
 .p_secondary_buf = p_tx2, \
 }

Macro for setting the TXTX transfer descriptor.

Enumeration Type Documentation

enum nrfx_twi_evt_type_t

TWI master driver event types.

Enumerator
NRFX_TWI_EVT_DONE	Transfer completed event.
NRFX_TWI_EVT_ADDRESS_NACK	Error event: NACK received after sending the address.
NRFX_TWI_EVT_DATA_NACK	Error event: NACK received after sending a data byte.

enum nrfx_twi_xfer_type_t

TWI master driver transfer types.

Enumerator
NRFX_TWI_XFER_TX	TX transfer.
NRFX_TWI_XFER_RX	RX transfer.
NRFX_TWI_XFER_TXRX	TX transfer followed by RX transfer with repeated start.
NRFX_TWI_XFER_TXTX	TX transfer followed by TX transfer with repeated start.

Function Documentation

size_t nrfx_twi_data_count_get ( nrfx_twi_t const *const p_instance )

Function for getting the transferred data count.

Parameters

[in] p_instance Pointer to the driver instance structure.

Returns: Data count.

void nrfx_twi_disable ( nrfx_twi_t const * p_instance )

Function for disabling the TWI instance.

Parameters

[in] p_instance Pointer to the driver instance structure.

void nrfx_twi_enable ( nrfx_twi_t const * p_instance )

Function for enabling the TWI instance.

Parameters

[in] p_instance Pointer to the driver instance structure.

nrfx_err_t nrfx_twi_init	(	nrfx_twi_t const *	p_instance,
		nrfx_twi_config_t const *	p_config,
		nrfx_twi_evt_handler_t	event_handler,
		void *	p_context
	)

Function for initializing the TWI driver instance.

Parameters

[in]	p_instance	Pointer to the driver instance structure.
[in]	p_config	Pointer to the structure with initial configuration.
[in]	event_handler	Event handler provided by the user. If NULL, blocking mode is enabled.
[in]	p_context	Context passed to event handler.

Return values

NRFX_SUCCESS	If initialization was successful.
NRFX_ERROR_INVALID_STATE	If the driver is in invalid state.
NRFX_ERROR_BUSY	If some other peripheral with the same instance ID is already in use. This is possible only if Peripheral Resource Sharing (PRS) module is enabled.

bool nrfx_twi_is_busy ( nrfx_twi_t const * p_instance )

Function for checking the TWI driver state.

Parameters

[in] p_instance TWI instance.

Return values

true	If the TWI driver is currently busy performing a transfer.
false	If the TWI driver is ready for a new transfer.

nrfx_err_t nrfx_twi_rx	(	nrfx_twi_t const *	p_instance,
		uint8_t	address,
		uint8_t *	p_data,
		size_t	length
	)

Function for reading data from a TWI slave.

The transmission will be stopped when an error occurs. If a transfer is ongoing, the function returns the error code NRFX_ERROR_BUSY.

Parameters

[in]	p_instance	Pointer to the driver instance structure.
[in]	address	Address of a specific slave device (only 7 LSB).
[in]	p_data	Pointer to a receive buffer.
[in]	length	Number of bytes to be received.

Return values

NRFX_SUCCESS	If the procedure was successful.
NRFX_ERROR_BUSY	If the driver is not ready for a new transfer.
NRFX_ERROR_INTERNAL	If an error was detected by hardware.
NRFX_ERROR_DRV_TWI_ERR_OVERRUN	If the unread data was replaced by new data
NRFX_ERROR_DRV_TWI_ERR_ANACK	If NACK received after sending the address in polling mode.
NRFX_ERROR_DRV_TWI_ERR_DNACK	If NACK received after sending a data byte in polling mode.

uint32_t nrfx_twi_stopped_event_get ( nrfx_twi_t const * p_instance )

Function for returning the address of a STOPPED TWI event.

A STOPPED event can be used to detect the end of a transfer if the NRFX_TWI_FLAG_NO_XFER_EVT_HANDLER option is used.

Parameters

[in] p_instance Pointer to the driver instance structure.

Returns: STOPPED event address.

nrfx_err_t nrfx_twi_tx	(	nrfx_twi_t const *	p_instance,
		uint8_t	address,
		uint8_t const *	p_data,
		size_t	length,
		bool	no_stop
	)

Function for sending data to a TWI slave.

The transmission will be stopped when an error occurs. If a transfer is ongoing, the function returns the error code NRFX_ERROR_BUSY.

Parameters

[in]	p_instance	Pointer to the driver instance structure.
[in]	address	Address of a specific slave device (only 7 LSB).
[in]	p_data	Pointer to a transmit buffer.
[in]	length	Number of bytes to send.
[in]	no_stop	If set, the stop condition is not generated on the bus after the transfer has completed successfully (allowing for a repeated start in the next transfer).

Return values

NRFX_SUCCESS	If the procedure was successful.
NRFX_ERROR_BUSY	If the driver is not ready for a new transfer.
NRFX_ERROR_INTERNAL	If an error was detected by hardware.
NRFX_ERROR_DRV_TWI_ERR_ANACK	If NACK received after sending the address in polling mode.
NRFX_ERROR_DRV_TWI_ERR_DNACK	If NACK received after sending a data byte in polling mode.

void nrfx_twi_uninit ( nrfx_twi_t const * p_instance )

Function for uninitializing the TWI instance.

Parameters

[in] p_instance Pointer to the driver instance structure.

nrfx_err_t nrfx_twi_xfer	(	nrfx_twi_t const *	p_instance,
		nrfx_twi_xfer_desc_t const *	p_xfer_desc,
		uint32_t	flags
	)

Function for preparing a TWI transfer.

The following transfer types can be configured (nrfx_twi_xfer_desc_t::type):

NRFX_TWI_XFER_TXRX: Write operation followed by a read operation (without STOP condition in between).
NRFX_TWI_XFER_TXTX: Write operation followed by a write operation (without STOP condition in between).
NRFX_TWI_XFER_TX: Write operation (with or without STOP condition).
NRFX_TWI_XFER_RX: Read operation (with STOP condition).

Note: TXRX and TXTX transfers are supported only in non-blocking mode.

Additional options are provided using the flags parameter:

NRFX_TWI_FLAG_NO_XFER_EVT_HANDLER: No user event handler after transfer completion. In most cases, this also means no interrupt at the end of the transfer.
NRFX_TWI_FLAG_TX_NO_STOP: No stop condition after TX transfer.

Note

Some flag combinations are invalid:

NRFX_TWI_FLAG_TX_NO_STOP with nrfx_twi_xfer_desc_t::type different than NRFX_TWI_XFER_TX

Parameters

[in]	p_instance	Pointer to the driver instance structure.
[in]	p_xfer_desc	Pointer to the transfer descriptor.
[in]	flags	Transfer options (0 for default settings).

Return values

NRFX_SUCCESS	If the procedure was successful.
NRFX_ERROR_BUSY	If the driver is not ready for a new transfer.
NRFX_ERROR_NOT_SUPPORTED	If the provided parameters are not supported.
NRFX_ERROR_INTERNAL	If an error was detected by hardware.
NRFX_ERROR_DRV_TWI_ERR_OVERRUN	If the unread data was replaced by new data (TXRX and RX)
NRFX_ERROR_DRV_TWI_ERR_ANACK	If NACK received after sending the address.
NRFX_ERROR_DRV_TWI_ERR_DNACK	If NACK received after sending a data byte.

Modules

Data Structures

Macros

Typedefs

Enumerations

Functions

Detailed Description

Macro Definition Documentation

Enumeration Type Documentation

Function Documentation