Inter-IC Sound (I2S) peripheral driver. More...

Topics
	I2S peripheral driver configuration

Data Structures
struct	nrfx_i2s_prescalers_t
	I2S prescalers structure. More...

struct	nrfx_i2s_clk_params_t
	Parameters use to describe I2S clock prescaling. More...

struct	nrfx_i2s_config_t
	I2S driver configuration structure. More...

struct	nrfx_i2s_t
	I2S driver instance data structure. More...

Macros
#define	NRFX_I2S_DEFAULT_CONFIG(_pin_sck, _pin_lrck, _pin_mck, _pin_sdout, _pin_sdin)
	I2S driver default configuration.

#define	NRFX_I2S_STATUS_NEXT_BUFFERS_NEEDED (1UL << 0)

#define	NRFX_I2S_STATUS_TRANSFER_STOPPED (1UL << 1)

#define	NRFX_I2S_INSTANCE(reg)
	Macro for creating an I2S driver instance.

Typedefs
typedef nrfy_i2s_xfer_desc_t	nrfx_i2s_buffers_t
	I2S driver buffers structure.

typedef void(*	nrfx_i2s_data_handler_t) (nrfx_i2s_buffers_t const *p_released, uint32_t status)
	I2S driver data handler type.

Functions
int	nrfx_i2s_init (nrfx_i2s_t p_instance, nrfx_i2s_config_t const p_config, nrfx_i2s_data_handler_t handler)
	Function for initializing the I2S driver.

void	nrfx_i2s_uninit (nrfx_i2s_t *p_instance)
	Function for uninitializing the I2S driver.

bool	nrfx_i2s_init_check (nrfx_i2s_t const *p_instance)
	Function for checking if the I2S driver instance is initialized.

int	nrfx_i2s_start (nrfx_i2s_t p_instance, nrfx_i2s_buffers_t const p_initial_buffers, uint8_t flags)
	Function for starting the continuous I2S transfer.

int	nrfx_i2s_next_buffers_set (nrfx_i2s_t p_instance, nrfx_i2s_buffers_t const p_buffers)
	Function for supplying the buffers to be used in the next part of the transfer.

void	nrfx_i2s_stop (nrfx_i2s_t *p_instance)
	Function for stopping the I2S transfer.

int	nrfx_i2s_prescalers_calc (nrfx_i2s_clk_params_t const clk_params, nrfx_i2s_prescalers_t prescalers)
	Function for calculating I2S clock prescaler values.

void	nrfx_i2s_irq_handler (nrfx_i2s_t *p_instance)
	Driver interrupt handler.

Detailed Description

Inter-IC Sound (I2S) peripheral driver.

Macro Definition Documentation

◆ NRFX_I2S_DEFAULT_CONFIG

#define NRFX_I2S_DEFAULT_CONFIG	(	_pin_sck,
		_pin_lrck,
		_pin_mck,
		_pin_sdout,
		_pin_sdin )

Value:

{                                                                                     \
    .sck_pin      = _pin_sck,                                                         \
    .lrck_pin     = _pin_lrck,                                                        \
    .mck_pin      = _pin_mck,                                                         \
    .sdout_pin    = _pin_sdout,                                                       \
    .sdin_pin     = _pin_sdin,                                                        \
    .irq_priority = NRFX_I2S_DEFAULT_CONFIG_IRQ_PRIORITY,                             \
    .mode         = NRF_I2S_MODE_MASTER,                                              \
    .format       = NRF_I2S_FORMAT_I2S,                                               \
    .alignment    = NRF_I2S_ALIGN_LEFT,                                               \
    .sample_width = NRF_I2S_SWIDTH_16BIT,                                             \
    .channels     = NRF_I2S_CHANNELS_LEFT,                                            \
    .prescalers   =                                                                   \
    {                                                                                 \
        .mck_setup    = NRF_I2S_MCK_32MDIV8,                                          \
        .ratio        = NRF_I2S_RATIO_32X,                                            \
        NRFX_COND_CODE_1(NRF_I2S_HAS_CLKCONFIG,                                       \
                        (.enable_bypass = false),                                     \
                        ())                                                           \
    },                                                                                \
    NRFX_COND_CODE_1(NRF_I2S_HAS_CLKCONFIG,                                           \
                     (.clksrc = NRF_I2S_CLKSRC_PCLK32M),                              \
                     ())                                                              \
}

I2S driver default configuration.

This configuration sets up I2S with the following options:

master mode
i2s data format
left alignment
sample width 16 bit
left channel enabled
MCK frequency 4 MHz
LRCK frequency 125 kHz

Parameters

[in]	_pin_sck	SCK pin number.
[in]	_pin_lrck	LRCK pin number.
[in]	_pin_mck	MCK pin number.
[in]	_pin_sdout	SDOUT pin number.
[in]	_pin_sdin	SDIN pin number.

◆ NRFX_I2S_INSTANCE

#define NRFX_I2S_INSTANCE ( reg )

Value:

{                                 \
    .p_reg = (NRF_I2S_Type *)reg, \
    .cb = {0},                    \
}

Macro for creating an I2S driver instance.

◆ NRFX_I2S_STATUS_NEXT_BUFFERS_NEEDED

#define NRFX_I2S_STATUS_NEXT_BUFFERS_NEEDED (1UL << 0)

The application must provide buffers that are to be used in the next part of the transfer. A call to nrfx_i2s_next_buffers_set must be done before the currently used buffers are completely processed (that is, the time remaining for supplying the next buffers depends on the used size of the buffers).

◆ NRFX_I2S_STATUS_TRANSFER_STOPPED

#define NRFX_I2S_STATUS_TRANSFER_STOPPED (1UL << 1)

The I2S peripheral has been stopped and all buffers that were passed to the driver have been released.

Typedef Documentation

◆ nrfx_i2s_data_handler_t

typedef void(* nrfx_i2s_data_handler_t) (nrfx_i2s_buffers_t const *p_released, uint32_t status)

I2S driver data handler type.

A data handling function of this type must be specified during the initialization of the driver. The driver will call this function when it finishes using buffers passed to it by the application, and when it needs to be provided with buffers for the next part of the transfer.

Note: The p_released pointer passed to this function is temporary and will be invalid after the function returns, hence it cannot be stored and used later. If needed, the pointed content (that is, buffers pointers) must be copied instead.

Parameters

[in] p_released Pointer to a structure with pointers to buffers passed previously to the driver that will no longer be accessed by it (they can be now safely released or used for another purpose, in particular for a next part of the transfer). This pointer will be NULL if the application did not supply the buffers for the next part of the transfer (via a call to nrfx_i2s_next_buffers_set) since the previous time the data handler signaled such need. This means that data corruption occurred (the previous buffers are used for the second time) and no buffers can be released at the moment. Both pointers in this structure are NULL when the handler is called for the first time after a transfer is started, because no data has been transferred yet at this point. In all successive calls, the pointers specify what has been sent (TX) and what has been received (RX) in the part of the transfer that has just been completed (provided that a given direction is enabled, see nrfx_i2s_start).

Note: Since the peripheral is stopped asynchronously, buffers that are released after the call to nrfx_i2s_stop are not used entirely. In this case, only a part (if any) of the TX buffer has been actually transmitted and only a part (if any) of the RX buffer is filled with received data.

Parameters

[in]

status

Bit field describing the current status of the transfer. It can be 0 or a combination of the following flags:

NRFX_I2S_STATUS_NEXT_BUFFERS_NEEDED
NRFX_I2S_STATUS_TRANSFER_STOPPED

Function Documentation

◆ nrfx_i2s_init()

int nrfx_i2s_init	(	nrfx_i2s_t *	p_instance,
		nrfx_i2s_config_t const *	p_config,
		nrfx_i2s_data_handler_t	handler )

Function for initializing the I2S driver.

Parameters

[in]	p_instance	Pointer to the driver instance structure.
[in]	p_config	Pointer to the structure with the initial configuration.
[in]	handler	Data handler provided by the user. Must not be NULL.

Return values

0	Initialization was successful.
-EALREADY	The driver is already initialized.
-EINVAL	The requested combination of configuration options is not allowed by the I2S peripheral.

◆ nrfx_i2s_init_check()

bool nrfx_i2s_init_check ( nrfx_i2s_t const * p_instance )

Function for checking if the I2S driver instance is initialized.

Parameters

[in] p_instance Pointer to the driver instance structure.

Return values

true	Instance is already initialized.
false	Instance is not initialized.

◆ nrfx_i2s_irq_handler()

void nrfx_i2s_irq_handler ( nrfx_i2s_t * p_instance )

Driver interrupt handler.

Parameters

[in] p_instance Pointer to the driver instance structure.

◆ nrfx_i2s_next_buffers_set()

int nrfx_i2s_next_buffers_set	(	nrfx_i2s_t *	p_instance,
		nrfx_i2s_buffers_t const *	p_buffers )

Function for supplying the buffers to be used in the next part of the transfer.

The application must call this function when the data handler receives NRFX_I2S_STATUS_NEXT_BUFFERS_NEEDED in the status parameter. The call can be done immediately from the data handler function or later, but it has to be done before the I2S peripheral finishes processing the buffers supplied previously. Otherwise, data corruption will occur.

Parameters

[in]	p_instance	Pointer to the driver instance structure.
[in]	p_buffers	Pointer to a structure specifying the buffers to be used in the upcoming part of the transfer.

Return values

0	If the operation was successful.
-EINPROGRESS	If the buffers were already supplied or the peripheral is currently being stopped.
-EACCES	The provided buffers are not placed in the Data RAM region.

See also: nrfx_i2s_data_handler_t

◆ nrfx_i2s_prescalers_calc()

int nrfx_i2s_prescalers_calc	(	nrfx_i2s_clk_params_t const *	clk_params,
		nrfx_i2s_prescalers_t *	prescalers )

Function for calculating I2S clock prescaler values.

Call this function to find suitable value for prescalers in nrfx_i2s_config_t structure.

Parameters

[in]	clk_params	Parameters used to describe clock prescaling.
[out]	prescalers	Prescaler structure pointer to be filled with prescaler values.

Return values

0	Suitable prescaler values were found.
-EINVAL	No suitable prescaler values were found.
-ENOTSUP	Requested configuration is not supported.

◆ nrfx_i2s_start()

int nrfx_i2s_start	(	nrfx_i2s_t *	p_instance,
		nrfx_i2s_buffers_t const *	p_initial_buffers,
		uint8_t	flags )

Function for starting the continuous I2S transfer.

The I2S data transfer can be performed in one of three modes: RX (reception) only, TX (transmission) only, or in both directions simultaneously. The mode is selected by specifying a proper buffer for a given direction in the call to this function or by passing NULL instead if this direction is to be disabled.

The length of the buffer (which is a common value for RX and TX if both directions are enabled) is specified in 32-bit words. One 32-bit memory word can either contain four 8-bit samples, two 16-bit samples, or one right-aligned 24-bit sample sign-extended to a 32-bit value. For a detailed memory mapping for different supported configurations, see the Product Specification.

Note: Peripherals using EasyDMA (including I2S) 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 -EACCES.

Parameters

[in]	p_instance	Pointer to the driver instance structure.
[in]	p_initial_buffers	Pointer to a structure specifying the buffers to be used in the initial part of the transfer (buffers for all consecutive parts are provided through the data handler).
[in]	flags	Transfer options (0 for default settings). Currently, no additional flags are available.

Return values

0	The operation was successful.
-EINPROGRESS	Transfer was already started or the driver has not been initialized.
-EACCES	The provided buffers are not placed in the Data RAM region.

◆ nrfx_i2s_stop()

void nrfx_i2s_stop ( nrfx_i2s_t * p_instance )

Function for stopping the I2S transfer.

Parameters

[in] p_instance Pointer to the driver instance structure.

◆ nrfx_i2s_uninit()

void nrfx_i2s_uninit ( nrfx_i2s_t * p_instance )

Function for uninitializing the I2S driver.

Parameters

[in] p_instance Pointer to the driver instance structure.

Topics

Data Structures

Macros

Typedefs

Functions

Detailed Description

Macro Definition Documentation

◆ NRFX_I2S_DEFAULT_CONFIG

◆ NRFX_I2S_INSTANCE

◆ NRFX_I2S_STATUS_NEXT_BUFFERS_NEEDED

◆ NRFX_I2S_STATUS_TRANSFER_STOPPED

Typedef Documentation

◆ nrfx_i2s_data_handler_t

Function Documentation

◆ nrfx_i2s_init()

◆ nrfx_i2s_init_check()

◆ nrfx_i2s_irq_handler()

◆ nrfx_i2s_next_buffers_set()

◆ nrfx_i2s_prescalers_calc()

◆ nrfx_i2s_start()

◆ nrfx_i2s_stop()

◆ nrfx_i2s_uninit()