SSC - Synchronous Serial Controller (I2S)

Driver for the I2S protocol using the SSC (Synchronous Serial Controller).

The Atmel SSC provides a synchronous communication link with external devices. It supports several serial synchronous communication protocols generally used in audio and telecom applications such as I2S, Short Frame Sync, Long Frame Sync, etc.

Macros
#define	SSC_I2S_TIMEOUT_VALUE   10000

Enumerations
enum	{   SSC_I2S_ERROR = -1,   SSC_I2S_OK = 0,   SSC_I2S_TIMEOUT = 1,   SSC_I2S_ERROR_ARGUMENT,   SSC_I2S_ERROR_RX,   SSC_I2S_ERROR_TX }
	Error codes used by SSC I2S driver. More...
enum	{   SSC_I2S_MODE_STEREO_OUT = 1,   SSC_I2S_MODE_STEREO_OUT_EXT_CLK,   SSC_I2S_MODE_SLAVE_STEREO_OUT,   SSC_I2S_MODE_SLAVE_STEREO_IN,   SSC_I2S_MODE_STEREO_OUT_MONO_IN,   SSC_I2S_MODE_RIGHT_IN,   SSC_I2S_MODE_STEREO_IN,   SSC_I2S_MODE_STEREO_OUT_STEREO_IN }
	SSC I2S modes. More...

Functions
void	ssc_i2s_disable_interrupts (volatile avr32_ssc_t *ssc, unsigned long int_mask)
	Disables the specified SSC interrupts. More...
void	ssc_i2s_enable_interrupts (volatile avr32_ssc_t *ssc, unsigned long int_mask)
	Enables the specified SSC interrupts. More...
unsigned long	ssc_i2s_get_status (volatile avr32_ssc_t *ssc)
	Returns the SSC status. More...
int	ssc_i2s_init (volatile avr32_ssc_t *ssc, unsigned int sample_frequency, unsigned int data_bit_res, unsigned int frame_bit_res, unsigned char mode, unsigned int pba_hz)
	Sets up registers and initializes SSC for use as I2S. More...
void	ssc_i2s_reset (volatile avr32_ssc_t *ssc)
	Resets the SSC module. More...
int	ssc_i2s_transfer (volatile avr32_ssc_t *ssc, unsigned int data)
	Transfers a single message of data. More...

#define SSC_I2S_TIMEOUT_VALUE   10000

Referenced by ssc_i2s_transfer().

anonymous enum

Error codes used by SSC I2S driver.

Enumerator
SSC_I2S_ERROR
SSC_I2S_OK
SSC_I2S_TIMEOUT
SSC_I2S_ERROR_ARGUMENT
SSC_I2S_ERROR_RX
SSC_I2S_ERROR_TX

anonymous enum

SSC I2S modes.

Enumerator
SSC_I2S_MODE_STEREO_OUT	Two output channels.
SSC_I2S_MODE_STEREO_OUT_EXT_CLK	Two output channels sampled with an external clock received from the SSC_RX_CLOCK line.
SSC_I2S_MODE_SLAVE_STEREO_OUT	Two output channels controlled by the DAC.
SSC_I2S_MODE_SLAVE_STEREO_IN	Two input channels controlled by the DAC.
SSC_I2S_MODE_STEREO_OUT_MONO_IN	Two output, one input channel.
SSC_I2S_MODE_RIGHT_IN	Right channel in. Used because one SSC only can manage one input channel at a time.
SSC_I2S_MODE_STEREO_IN	Two input channels.
SSC_I2S_MODE_STEREO_OUT_STEREO_IN	Two output channels and two input channels.

void ssc_i2s_disable_interrupts	(	volatile avr32_ssc_t *	ssc,
		unsigned long	int_mask
	)

Disables the specified SSC interrupts.

Parameters

ssc	Base address of the SSC instance.
int_mask	Bit-mask of SSC interrupts (AVR32_SSC_IDR_x_MASK).

References cpu_irq_disable, cpu_irq_enable, and cpu_irq_is_enabled.

void ssc_i2s_enable_interrupts	(	volatile avr32_ssc_t *	ssc,
		unsigned long	int_mask
	)

Enables the specified SSC interrupts.

Parameters

ssc	Base address of the SSC instance.
int_mask	Bit-mask of SSC interrupts (AVR32_SSC_IER_x_MASK).

unsigned long ssc_i2s_get_status

(

volatile avr32_ssc_t *

ssc

)

Returns the SSC status.

Parameters

ssc	Base address of the SSC instance.

Returns

The SSC Status Register.

int ssc_i2s_init	(	volatile avr32_ssc_t *	ssc,
		unsigned int	sample_frequency,
		unsigned int	data_bit_res,
		unsigned int	frame_bit_res,
		unsigned char	mode,
		unsigned int	pba_hz
	)

Sets up registers and initializes SSC for use as I2S.

Parameters

ssc	Pointer to the correct volatile avr32_ssc_t struct
sample_frequency	The sample frequency given in Hz
data_bit_res	Number of significant data bits in an I2S channel frame
frame_bit_res	Total number of bits in an I2S channel frame
mode	I2S-mode SSC_I2S_MODE_STEREO_OUT SSC_I2S_MODE_STEREO_OUT_EXT_CLK SSC_I2S_MODE_SLAVE_STEREO_OUT SSC_I2S_MODE_STEREO_OUT_MONO_IN SSC_I2S_MODE_RIGHT_IN SSC_I2S_MODE_STEREO_IN SSC_I2S_MODE_STEREO_OUT_STEREO_IN
pba_hz	The clock speed of the PBA bus in Hz.

Returns

Status

Return values

SSC_I2S_OK	when no error occurred.
SSC_I2S_ERROR_ARGUMENT	when invalid arguments are passed

Todo:

check input values

References set_clock_divider(), SSC_I2S_MODE_RIGHT_IN, SSC_I2S_MODE_SLAVE_STEREO_IN, SSC_I2S_MODE_SLAVE_STEREO_OUT, SSC_I2S_MODE_STEREO_OUT, SSC_I2S_MODE_STEREO_OUT_EXT_CLK, SSC_I2S_MODE_STEREO_OUT_MONO_IN, SSC_I2S_OK, and ssc_i2s_reset().

Referenced by aic23b_dac_setup().

void ssc_i2s_reset

(

volatile avr32_ssc_t *

ssc

)

Resets the SSC module.

Parameters

ssc	pointer to the correct volatile avr32_ssc_t struct

Referenced by aic23b_dac_stop(), and ssc_i2s_init().

int ssc_i2s_transfer	(	volatile avr32_ssc_t *	ssc,
		unsigned int	data
	)

Transfers a single message of data.

Parameters

ssc	Pointer to the correct volatile avr32_ssc_t struct
data	The data to transfer

Returns

Status

Return values

SSC_I2S_OK	when no error occurred.
SSC_I2S_TIMEOUT	when a timeout occurred while trying to transfer

References data, SSC_I2S_OK, SSC_I2S_TIMEOUT, and SSC_I2S_TIMEOUT_VALUE.