Two Wire Slave interface (TWIS) peripheral driver. More...

Modules
	TWIS peripheral driver configuration

Data Structures
struct	nrfx_twis_t
	TWIS driver instance data structure. More...

struct	nrfx_twis_evt_t
	TWIS driver event structure. More...

struct	nrfx_twis_config_t
	Structure for TWIS configuration. More...

Macros
#define	NRFX_TWIS_INSTANCE(id)
	Macro for creating a TWIS driver instance. More...

#define	NRFX_TWIS_DEFAULT_CONFIG
	Generate default configuration for TWIS driver instance. More...

Typedefs
typedef void(*	nrfx_twis_event_handler_t )(nrfx_twis_evt_t const *p_event)
	TWI slave event callback function type. More...

Enumerations
enum	{ NRFX_TWIS_ENABLED_COUNT }

enum	nrfx_twis_evt_type_t { NRFX_TWIS_EVT_READ_REQ, NRFX_TWIS_EVT_READ_DONE, NRFX_TWIS_EVT_READ_ERROR, NRFX_TWIS_EVT_WRITE_REQ, NRFX_TWIS_EVT_WRITE_DONE, NRFX_TWIS_EVT_WRITE_ERROR, NRFX_TWIS_EVT_GENERAL_ERROR }
	Event callback function event definitions. More...

enum	nrfx_twis_error_t { NRFX_TWIS_ERROR_OVERFLOW = NRF_TWIS_ERROR_OVERFLOW, NRFX_TWIS_ERROR_DATA_NACK = NRF_TWIS_ERROR_DATA_NACK, NRFX_TWIS_ERROR_OVERREAD = NRF_TWIS_ERROR_OVERREAD, NRFX_TWIS_ERROR_UNEXPECTED_EVENT = 1 << 8 }
	Possible error sources. More...

Functions
nrfx_err_t	nrfx_twis_init (nrfx_twis_t const p_instance, nrfx_twis_config_t const p_config, nrfx_twis_event_handler_t event_handler)
	Function for initializing the TWIS driver instance. More...

void	nrfx_twis_uninit (nrfx_twis_t const *p_instance)
	Function for uninitializing the TWIS driver instance. More...

void	nrfx_twis_enable (nrfx_twis_t const *p_instance)
	Enable TWIS instance. More...

void	nrfx_twis_disable (nrfx_twis_t const *p_instance)
	Disable TWIS instance. More...

uint32_t	nrfx_twis_error_get_and_clear (nrfx_twis_t const *p_instance)
	Get and clear last error flags. More...

nrfx_err_t	nrfx_twis_tx_prepare (nrfx_twis_t const p_instance, void const p_buf, size_t size)
	Prepare data for sending. More...

__STATIC_INLINE size_t	nrfx_twis_tx_amount (nrfx_twis_t const *p_instance)
	Get number of transmitted bytes. More...

nrfx_err_t	nrfx_twis_rx_prepare (nrfx_twis_t const p_instance, void p_buf, size_t size)
	Prepare data for receiving. More...

__STATIC_INLINE size_t	nrfx_twis_rx_amount (nrfx_twis_t const *p_instance)
	Get number of received bytes. More...

bool	nrfx_twis_is_busy (nrfx_twis_t const *p_instance)
	Function checks if driver is busy right now. More...

bool	nrfx_twis_is_waiting_tx_buff (nrfx_twis_t const *p_instance)
	Function checks if driver is waiting for tx buffer. More...

bool	nrfx_twis_is_waiting_rx_buff (nrfx_twis_t const *p_instance)
	Function checks if driver is waiting for rx buffer. More...

bool	nrfx_twis_is_pending_tx (nrfx_twis_t const *p_instance)
	Check if driver is sending data. More...

bool	nrfx_twis_is_pending_rx (nrfx_twis_t const *p_instance)
	Check if driver is receiving data. More...

void	nrfx_twis_0_irq_handler (void)

void	nrfx_twis_1_irq_handler (void)

void	nrfx_twis_2_irq_handler (void)

void	nrfx_twis_3_irq_handler (void)

Detailed Description

Two Wire Slave interface (TWIS) peripheral driver.

Macro Definition Documentation

#define NRFX_TWIS_DEFAULT_CONFIG

Value:

{ \
 .addr = { NRFX_TWIS_DEFAULT_CONFIG_ADDR0, \
 NRFX_TWIS_DEFAULT_CONFIG_ADDR1 }, \
 .scl = 31, \
 .scl_pull = (nrf_gpio_pin_pull_t)NRFX_TWIS_DEFAULT_CONFIG_SCL_PULL, \
 .sda = 31, \
 .sda_pull = (nrf_gpio_pin_pull_t)NRFX_TWIS_DEFAULT_CONFIG_SDA_PULL, \
 .interrupt_priority = NRFX_TWIS_DEFAULT_CONFIG_IRQ_PRIORITY \
}

Generate default configuration for TWIS driver instance.

#define NRFX_TWIS_INSTANCE ( id )

Value:

{ \
 .p_reg = NRFX_CONCAT_2(NRF_TWIS, id), \
 .drv_inst_idx = NRFX_CONCAT_3(NRFX_TWIS, id, _INST_IDX), \
}

Macro for creating a TWIS driver instance.

Typedef Documentation

typedef void(* nrfx_twis_event_handler_t)(nrfx_twis_evt_t const *p_event)

TWI slave event callback function type.

Parameters

[in] p_event Event information structure.

Enumeration Type Documentation

enum nrfx_twis_error_t

Possible error sources.

This is flag enum - values from this enum can be connected using logical or operator.

Note: We could use directly nrf_twis_error_t. Error type enum is redefined here because of possible future extension (eg. supporting timeouts and synchronous mode).

Enumerator
NRFX_TWIS_ERROR_OVERFLOW	RX buffer overflow detected, and prevented.
NRFX_TWIS_ERROR_DATA_NACK	NACK sent after receiving a data byte.
NRFX_TWIS_ERROR_OVERREAD	TX buffer over-read detected, and prevented.
NRFX_TWIS_ERROR_UNEXPECTED_EVENT	Unexpected event detected by state machine.

enum nrfx_twis_evt_type_t

Event callback function event definitions.

Enumerator
NRFX_TWIS_EVT_READ_REQ	Read request detected. If there is no buffer prepared, buf_req flag in the even will be set. Call then nrfx_twis_tx_prepare to give parameters for buffer.
NRFX_TWIS_EVT_READ_DONE	Read request has finished - free any data.
NRFX_TWIS_EVT_READ_ERROR	Read request finished with error.
NRFX_TWIS_EVT_WRITE_REQ	Write request detected. If there is no buffer prepared, buf_req flag in the even will be set. Call then nrfx_twis_rx_prepare to give parameters for buffer.
NRFX_TWIS_EVT_WRITE_DONE	Write request has finished - process data.
NRFX_TWIS_EVT_WRITE_ERROR	Write request finished with error.
NRFX_TWIS_EVT_GENERAL_ERROR	Error that happens not inside WRITE or READ transaction.

Function Documentation

void nrfx_twis_disable ( nrfx_twis_t const * p_instance )

Disable TWIS instance.

Disabling TWIS instance gives possibility to turn off the TWIS while holding configuration done by nrfx_twis_init.

Parameters

p_instance Pointer to the driver instance structure.

void nrfx_twis_enable ( nrfx_twis_t const * p_instance )

Enable TWIS instance.

This function enables TWIS instance. Function defined if there is needs for dynamically enabling and disabling the peripheral. Use nrfx_twis_enable and nrfx_twis_disable functions. They do not change any configuration registers.

Parameters

p_instance Pointer to the driver instance structure.

uint32_t nrfx_twis_error_get_and_clear ( nrfx_twis_t const * p_instance )

Get and clear last error flags.

Function gets information about errors. This is also the only possibility to exit from error substate of the internal state machine.

Parameters

[in] p_instance Pointer to the driver instance structure.

Returns: Error flags defined in nrfx_twis_error_t.

Attention: This function clears error state and flags.

nrfx_err_t nrfx_twis_init	(	nrfx_twis_t const *	p_instance,
		nrfx_twis_config_t const *	p_config,
		nrfx_twis_event_handler_t	event_handler
	)

Function for initializing the TWIS driver instance.

Function initializes and enables TWIS driver.

Attention: After driver initialization enable it by nrfx_twis_enable.

Parameters

[in] p_instance Pointer to the driver instance structure.

Attention: p_instance has to be global object. It would be used by interrupts so make it sure that object would not be destroyed when function is leaving.

Parameters

[in]	p_config	Pointer to the structure with initial configuration.
[in]	event_handler	Event handler provided by the user.

Return values

NRFX_SUCCESS	If initialization was successful.
NRFX_ERROR_INVALID_STATE	If the driver is already initialized.
NRFX_ERROR_BUSY	If some other peripheral with the same instance ID is already in use. This is possible only if NRFX_PRS_ENABLED is set to a value other than zero.

bool nrfx_twis_is_busy ( nrfx_twis_t const * p_instance )

Function checks if driver is busy right now.

Actual driver substate is tested. If driver is in any other state than IDLE or ERROR this function returns true.

Parameters

[in] p_instance Pointer to the driver instance structure.

Return values

true	Driver is in state other than ERROR or IDLE.
false	There is no transmission pending.

bool nrfx_twis_is_pending_rx ( nrfx_twis_t const * p_instance )

Check if driver is receiving data.

If this function returns true, it means that there is ongoing input transmission.

Parameters

[in] p_instance Pointer to the driver instance structure.

Return values

true	There is ongoing input transmission.
false	Driver is in other state.

bool nrfx_twis_is_pending_tx ( nrfx_twis_t const * p_instance )

Check if driver is sending data.

If this function returns true, it means that there is ongoing output transmission.

Parameters

[in] p_instance Pointer to the driver instance structure.

Return values

true	There is ongoing output transmission.
false	Driver is in other state.

bool nrfx_twis_is_waiting_rx_buff ( nrfx_twis_t const * p_instance )

Function checks if driver is waiting for rx buffer.

If this function returns true, it means that driver is staled expecting of the nrfx_twis_rx_prepare function call.

Parameters

[in] p_instance Pointer to the driver instance structure.

Return values

true	Driver waits for nrfx_twis_rx_prepare.
false	Driver is not in the state where it waits for preparing rx buffer.

bool nrfx_twis_is_waiting_tx_buff ( nrfx_twis_t const * p_instance )

Function checks if driver is waiting for tx buffer.

If this function returns true, it means that driver is stalled expecting of the nrfx_twis_tx_prepare function call.

Parameters

[in] p_instance Pointer to the driver instance structure.

Return values

true	Driver waits for nrfx_twis_tx_prepare.
false	Driver is not in the state where it waits for preparing tx buffer.

__STATIC_INLINE size_t nrfx_twis_rx_amount ( nrfx_twis_t const * p_instance )

Get number of received bytes.

Function returns number of bytes received. This function may be called after NRFX_TWIS_EVT_WRITE_DONE or NRFX_TWIS_EVT_WRITE_ERROR events.

Parameters

[in] p_instance Pointer to the driver instance structure.

Returns: Number of bytes received.

nrfx_err_t nrfx_twis_rx_prepare	(	nrfx_twis_t const *	p_instance,
		void *	p_buf,
		size_t	size
	)

Prepare data for receiving.

This function should be used in response for NRFX_TWIS_EVT_WRITE_REQ event.

Note: Peripherals using EasyDMA (including TWIS) require the transfer buffers to be placed in the Data RAM region. If this condition is not met, this function will fail with the error code NRFX_ERROR_INVALID_ADDR.

Parameters

[in]	p_instance	Pointer to the driver instance structure.
[in]	p_buf	Buffer that would be filled with received data.

Attention: Receiving buffer has to be placed in RAM.

Parameters

size	Size of the buffer (maximum amount of data to receive).

Return values

NRFX_SUCCESS	Preparation finished properly.
NRFX_ERROR_INVALID_ADDR	Given p_buf is not placed inside the RAM.
NRFX_ERROR_INVALID_LENGTH	Wrong value in size parameter.
NRFX_ERROR_INVALID_STATE	Module not initialized or not enabled.

__STATIC_INLINE size_t nrfx_twis_tx_amount ( nrfx_twis_t const * p_instance )

Get number of transmitted bytes.

Function returns number of bytes sent. This function may be called after NRFX_TWIS_EVT_READ_DONE or NRFX_TWIS_EVT_READ_ERROR events.

Parameters

[in] p_instance Pointer to the driver instance structure.

Returns: Number of bytes sent.

nrfx_err_t nrfx_twis_tx_prepare	(	nrfx_twis_t const *	p_instance,
		void const *	p_buf,
		size_t	size
	)

Prepare data for sending.

This function should be used in response for NRFX_TWIS_EVT_READ_REQ event.

Note: Peripherals using EasyDMA (including TWIS) require the transfer buffers to be placed in the Data RAM region. If this condition is not met, this function will fail with the error code NRFX_ERROR_INVALID_ADDR.

Parameters

[in]	p_instance	Pointer to the driver instance structure.
[in]	p_buf	Transmission buffer.

Attention: Transmission buffer has to be placed in RAM.

Parameters

size	Maximum number of bytes that master may read from buffer given.

Return values

NRFX_SUCCESS	Preparation finished properly.
NRFX_ERROR_INVALID_ADDR	Given p_buf is not placed inside the RAM.
NRFX_ERROR_INVALID_LENGTH	Wrong value in size parameter.
NRFX_ERROR_INVALID_STATE	Module not initialized or not enabled.

void nrfx_twis_uninit ( nrfx_twis_t const * p_instance )

Function for uninitializing the TWIS driver instance.

Function initializes the peripheral and resets all registers to default values.

Parameters

[in] p_instance Pointer to the driver instance structure.

Note: It is safe to call nrfx_twis_uninit even before initialization. Actually nrfx_twis_init function calls this function to make sure that TWIS state is known.; If TWIS driver was in uninitialized state before calling this function, selected pins would not be reset to default configuration.

Modules

Data Structures

Macros

Typedefs

Enumerations

Functions

Detailed Description

Macro Definition Documentation

Typedef Documentation

Enumeration Type Documentation

Function Documentation