TWI master APIs. More...

Modules
	TWI/TWIM peripheral driver configuration

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

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

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

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

Macros
#define	TWI0_INCR 0

#define	TWI1_INCR 0

#define	ENABLED_TWI_COUNT (TWI0_INCR + TWI1_INCR)

#define	TWIM_ONLY ( defined(TWIM_PRESENT) && !defined(TWI_PRESENT))

#define	TWI_TWIM_PRESENT ( defined(TWIM_PRESENT) && defined(TWI_PRESENT))

#define	TWI_ONLY (!defined(TWIM_PRESENT) && defined(TWI_PRESENT))

#define	TWI0_WITH_DMA (defined(TWI0_USE_EASY_DMA) && TWI0_USE_EASY_DMA && TWI0_ENABLED)

#define	TWI1_WITH_DMA (defined(TWI1_USE_EASY_DMA) && TWI1_USE_EASY_DMA && TWI1_ENABLED)

#define	TWI0_WITHOUT_DMA (defined(TWI0_USE_EASY_DMA) && !TWI0_USE_EASY_DMA && TWI0_ENABLED)

#define	TWI1_WITHOUT_DMA (defined(TWI1_USE_EASY_DMA) && !TWI1_USE_EASY_DMA && TWI1_ENABLED)

#define	NRF_DRV_TWI_PERIPHERAL(id) (void *)CONCAT_2(NRF_TWI, id)

#define	TWI0_INSTANCE_INDEX 0

#define	TWI1_INSTANCE_INDEX TWI0_INSTANCE_INDEX+TWI0_INCR

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

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

#define	NRF_DRV_TWI_FLAG_TX_POSTINC (1UL << 0)

#define	NRF_DRV_TWI_FLAG_RX_POSTINC (1UL << 1)

#define	NRF_DRV_TWI_FLAG_NO_XFER_EVT_HANDLER (1UL << 2)

#define	NRF_DRV_TWI_FLAG_HOLD_XFER (1UL << 3)

#define	NRF_DRV_TWI_FLAG_REPEATED_XFER (1UL << 4)

#define	NRF_DRV_TWI_FLAG_TX_NO_STOP (1UL << 5)

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

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

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

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

Typedefs
typedef nrf_twim_frequency_t	nrf_twi_frequency_t

typedef nrf_twim_error_t	nrf_twi_error_t

typedef void(*	nrf_drv_twi_evt_handler_t )(nrf_drv_twi_evt_t const p_event, void p_context)
	TWI event handler prototype.

Enumerations
enum	nrf_drv_twi_evt_type_t { NRF_DRV_TWI_EVT_DONE, NRF_DRV_TWI_EVT_ADDRESS_NACK, NRF_DRV_TWI_EVT_DATA_NACK }
	TWI master driver event types. More...

enum	nrf_drv_twi_xfer_type_t { NRF_DRV_TWI_XFER_TX, NRF_DRV_TWI_XFER_RX, NRF_DRV_TWI_XFER_TXRX, NRF_DRV_TWI_XFER_TXTX }
	TWI master driver transfer types. More...

Functions
ret_code_t	nrf_drv_twi_init (nrf_drv_twi_t const p_instance, nrf_drv_twi_config_t const p_config, nrf_drv_twi_evt_handler_t event_handler, void *p_context)
	Function for initializing the TWI driver instance. More...

void	nrf_drv_twi_uninit (nrf_drv_twi_t const *p_instance)
	Function for uninitializing the TWI instance. More...

void	nrf_drv_twi_enable (nrf_drv_twi_t const *p_instance)
	Function for enabling the TWI instance. More...

void	nrf_drv_twi_disable (nrf_drv_twi_t const *p_instance)
	Function for disabling the TWI instance. More...

ret_code_t	nrf_drv_twi_tx (nrf_drv_twi_t const p_instance, uint8_t address, uint8_t const p_data, uint8_t length, bool no_stop)
	Function for sending data to a TWI slave. More...

ret_code_t	nrf_drv_twi_rx (nrf_drv_twi_t const p_instance, uint8_t address, uint8_t p_data, uint8_t length)
	Function for reading data from a TWI slave. More...

ret_code_t	nrf_drv_twi_xfer (nrf_drv_twi_t const p_instance, nrf_drv_twi_xfer_desc_t const p_xfer_desc, uint32_t flags)
	Function for preparing a TWI transfer. More...

bool	nrf_drv_twi_is_busy (nrf_drv_twi_t const *p_instance)
	Function for checking the TWI driver state. More...

uint32_t	nrf_drv_twi_data_count_get (nrf_drv_twi_t const *const p_instance)
	Function for getting the transferred data count. More...

uint32_t	nrf_drv_twi_start_task_get (nrf_drv_twi_t const *p_instance, nrf_drv_twi_xfer_type_t xfer_type)
	Function for returning the address of a TWI/TWIM start task. More...

uint32_t	nrf_drv_twi_stopped_event_get (nrf_drv_twi_t const *p_instance)
	Function for returning the address of a STOPPED TWI/TWIM event. More...

Detailed Description

TWI master APIs.

Macro Definition Documentation

#define NRF_DRV_TWI_DEFAULT_CONFIG

Value:

{ \
 .frequency = (nrf_twi_frequency_t)TWI_DEFAULT_CONFIG_FREQUENCY, \
 .scl = 31, \
 .sda = 31, \
 .interrupt_priority = TWI_DEFAULT_CONFIG_IRQ_PRIORITY, \
 .clear_bus_init = TWI_DEFAULT_CONFIG_CLR_BUS_INIT, \
 .hold_bus_uninit = TWI_DEFAULT_CONFIG_HOLD_BUS_UNINIT, \
}

TWI master driver instance default configuration.

#define NRF_DRV_TWI_FLAG_HOLD_XFER (1UL << 3)

Set up the transfer but do not start it.

#define NRF_DRV_TWI_FLAG_NO_XFER_EVT_HANDLER (1UL << 2)

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

#define NRF_DRV_TWI_FLAG_REPEATED_XFER (1UL << 4)

Flag indicating that the transfer will be executed multiple times.

#define NRF_DRV_TWI_FLAG_RX_POSTINC (1UL << 1)

RX buffer address incremented after transfer.

#define NRF_DRV_TWI_FLAG_TX_NO_STOP (1UL << 5)

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

#define NRF_DRV_TWI_FLAG_TX_POSTINC (1UL << 0)

TX buffer address incremented after transfer.

#define NRF_DRV_TWI_INSTANCE ( id )

Value:

{ \
 .reg = {NRF_DRV_TWI_PERIPHERAL(id)}, \
 .drv_inst_idx = CONCAT_3(TWI, id, _INSTANCE_INDEX), \
 .use_easy_dma = TWI_USE_EASY_DMA(id) \
}

Macro for creating a TWI master driver instance.

#define NRF_DRV_TWI_XFER_DESC_RX	(	addr,
		p_data,
		length
	)

Value:

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

Macro for setting the RX transfer descriptor.

#define NRF_DRV_TWI_XFER_DESC_TX	(	addr,
		p_data,
		length
	)

Value:

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

Macro for setting the TX transfer descriptor.

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

Value:

{ \
 .type = NRF_DRV_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 NRF_DRV_TWI_XFER_DESC_TXTX	(	addr,
		p_tx,
		tx_len,
		p_tx2,
		tx_len2
	)

Value:

{ \
 .type = NRF_DRV_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 nrf_drv_twi_evt_type_t

TWI master driver event types.

Enumerator
NRF_DRV_TWI_EVT_DONE	Transfer completed event.
NRF_DRV_TWI_EVT_ADDRESS_NACK	Error event: NACK received after sending the address.
NRF_DRV_TWI_EVT_DATA_NACK	Error event: NACK received after sending a data byte.

enum nrf_drv_twi_xfer_type_t

TWI master driver transfer types.

Enumerator
NRF_DRV_TWI_XFER_TX	TX transfer.
NRF_DRV_TWI_XFER_RX	RX transfer.
NRF_DRV_TWI_XFER_TXRX	TX transfer followed by RX transfer with repeated start.
NRF_DRV_TWI_XFER_TXTX	TX transfer followed by TX transfer with repeated start.

Function Documentation

uint32_t nrf_drv_twi_data_count_get ( nrf_drv_twi_t const *const p_instance )

Function for getting the transferred data count.

This function provides valid results only in legacy mode.

Parameters

[in] p_instance Pointer to the driver instance structure.

Returns: Data count.

void nrf_drv_twi_disable ( nrf_drv_twi_t const * p_instance )

Function for disabling the TWI instance.

Parameters

[in] p_instance Pointer to the driver instance structure.

void nrf_drv_twi_enable ( nrf_drv_twi_t const * p_instance )

Function for enabling the TWI instance.

Parameters

[in] p_instance Pointer to the driver instance structure.

ret_code_t nrf_drv_twi_init	(	nrf_drv_twi_t const *	p_instance,
		nrf_drv_twi_config_t const *	p_config,
		nrf_drv_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	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

NRF_SUCCESS	If initialization was successful.
NRF_ERROR_INVALID_STATE	If the driver is in invalid state.
NRF_ERROR_BUSY	If some other peripheral with the same instance ID is already in use. This is possible only if PERIPHERAL_RESOURCE_SHARING_ENABLED is set to a value other than zero.

bool nrf_drv_twi_is_busy ( nrf_drv_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.

ret_code_t nrf_drv_twi_rx	(	nrf_drv_twi_t const *	p_instance,
		uint8_t	address,
		uint8_t *	p_data,
		uint8_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 NRF_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

NRF_SUCCESS	If the procedure was successful.
NRF_ERROR_BUSY	If the driver is not ready for a new transfer.
NRF_ERROR_INTERNAL	If an error was detected by hardware.
NRF_ERROR_DRV_TWI_ERR_OVERRUN	If the unread data was replaced by new data
NRF_ERROR_DRV_TWI_ERR_ANACK	If NACK received after sending the address in polling mode.
NRF_ERROR_DRV_TWI_ERR_DNACK	If NACK received after sending a data byte in polling mode.

uint32_t nrf_drv_twi_start_task_get	(	nrf_drv_twi_t const *	p_instance,
		nrf_drv_twi_xfer_type_t	xfer_type
	)

Function for returning the address of a TWI/TWIM start task.

This function should be used if nrf_drv_twi_xfer was called with the flag NRF_DRV_TWI_FLAG_HOLD_XFER. In that case, the transfer is not started by the driver, but it must be started externally by PPI.

Parameters

[in]	p_instance	Pointer to the driver instance structure.
[in]	xfer_type	Transfer type used in the last call of the nrf_drv_twi_xfer function.

Returns: Start task address (TX or RX) depending on the value of xfer_type.

uint32_t nrf_drv_twi_stopped_event_get ( nrf_drv_twi_t const * p_instance )

Function for returning the address of a STOPPED TWI/TWIM event.

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

Parameters

[in] p_instance Pointer to the driver instance structure.

Returns: STOPPED event address.

ret_code_t nrf_drv_twi_tx	(	nrf_drv_twi_t const *	p_instance,
		uint8_t	address,
		uint8_t const *	p_data,
		uint8_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 NRF_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

NRF_SUCCESS	If the procedure was successful.
NRF_ERROR_BUSY	If the driver is not ready for a new transfer.
NRF_ERROR_INTERNAL	If an error was detected by hardware.
NRF_ERROR_INVALID_ADDR	If the EasyDMA is used and memory adress in not in RAM.
NRF_ERROR_DRV_TWI_ERR_ANACK	If NACK received after sending the address in polling mode.
NRF_ERROR_DRV_TWI_ERR_DNACK	If NACK received after sending a data byte in polling mode.

void nrf_drv_twi_uninit ( nrf_drv_twi_t const * p_instance )

Function for uninitializing the TWI instance.

Parameters

[in] p_instance Pointer to the driver instance structure.

ret_code_t nrf_drv_twi_xfer	(	nrf_drv_twi_t const *	p_instance,
		nrf_drv_twi_xfer_desc_t const *	p_xfer_desc,
		uint32_t	flags
	)

Function for preparing a TWI transfer.

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

NRF_DRV_TWI_XFER_TXRX: Write operation followed by a read operation (without STOP condition in between).
NRF_DRV_TWI_XFER_TXTX: Write operation followed by a write operation (without STOP condition in between).
NRF_DRV_TWI_XFER_TX: Write operation (with or without STOP condition).
NRF_DRV_TWI_XFER_RX: Read operation (with STOP condition).

Additional options are provided using the flags parameter:

NRF_DRV_TWI_FLAG_TX_POSTINC and NRF_DRV_TWI_FLAG_RX_POSTINC: Post-incrementation of buffer addresses. Supported only by TWIM.
NRF_DRV_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.
NRF_DRV_TWI_FLAG_HOLD_XFER: Driver is not starting the transfer. Use this flag if the transfer is triggered externally by PPI. Supported only by TWIM. Use nrf_drv_twi_start_task_get to get the address of the start task.
NRF_DRV_TWI_FLAG_REPEATED_XFER: Prepare for repeated transfers. You can set up a number of transfers that will be triggered externally (for example by PPI). An example is a TXRX transfer with the options NRF_DRV_TWI_FLAG_RX_POSTINC, NRF_DRV_TWI_FLAG_NO_XFER_EVT_HANDLER, and NRF_DRV_TWI_FLAG_REPEATED_XFER. After the transfer is set up, a set of transfers can be triggered by PPI that will read, for example, the same register of an external component and put it into a RAM buffer without any interrupts. nrf_drv_twi_stopped_event_get can be used to get the address of the STOPPED event, which can be used to count the number of transfers. If NRF_DRV_TWI_FLAG_REPEATED_XFER is used, the driver does not set the driver instance into busy state, so you must ensure that the next transfers are set up when TWIM is not active. Supported only by TWIM.
NRF_DRV_TWI_FLAG_TX_NO_STOP: No stop condition after TX transfer.

Note

Some flag combinations are invalid:

NRF_DRV_TWI_FLAG_TX_NO_STOP with nrf_drv_twi_xfer_desc_t::type different than NRF_DRV_TWI_XFER_TX
NRF_DRV_TWI_FLAG_REPEATED_XFER with nrf_drv_twi_xfer_desc_t::type set to NRF_DRV_TWI_XFER_TXTX

If nrf_drv_twi_xfer_desc_t::type is set to NRF_DRV_TWI_XFER_TX and the NRF_DRV_TWI_FLAG_TX_NO_STOP and NRF_DRV_TWI_FLAG_REPEATED_XFER flags are set, two tasks must be used to trigger a transfer: TASKS_RESUME followed by TASKS_STARTTX. If no stop condition is generated, TWIM is in SUSPENDED state. Therefore, it must be resumed before the transfer can be started.

Note: This function should be used only if the instance is configured to work in non-blocking mode. If the function is used in blocking mode, the driver asserts.; If you are using this function with TWI, the only supported flag is NRF_DRV_TWI_FLAG_TX_NO_STOP. All other flags require TWIM.

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

NRF_SUCCESS	If the procedure was successful.
NRF_ERROR_BUSY	If the driver is not ready for a new transfer.
NRF_ERROR_NOT_SUPPORTED	If the provided parameters are not supported.
NRF_ERROR_INTERNAL	If an error was detected by hardware.
NRF_ERROR_INVALID_ADDR	If the EasyDMA is used and memory adress in not in RAM
NRF_ERROR_DRV_TWI_ERR_OVERRUN	If the unread data was replaced by new data (TXRX and RX)
NRF_ERROR_DRV_TWI_ERR_ANACK	If NACK received after sending the address.
NRF_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