SPI Slave Peripheral Driver

The section describes the programming interface of the SPI slave mode Peripheral driver. More...

Data Structures
struct	spi_slave_callbacks_t
	The set of callbacks used for SPI slave mode. More...
struct	spi_slave_user_config_t
	Definition of application implemented configuration and callback. More...

SPI Slave
void	spi_slave_init (uint32_t instance, const spi_slave_user_config_t *config)
	Initializes the SPI module. More...
void	spi_slave_shutdown (uint32_t instance)
	De-initializes the device. More...

SPI Slave Peripheral Driver

Overview

The SPI slave peripheral driver provides an easy way to use an SPI peripheral in slave mode.Data transfer is performed through callback functions.

Callbacks

To use this driver, first define several application callbacks. These are the callback functions that are set in the spi_slave_callbacks_t structure.The three callbacks are:

• Data source
• Data sink
• Error notification

The first two callbacks are used to send and receive data. The third callback is invoked if an error occurs.The prototypes for the three callbacks are:

status_t dataSource(uint8_t * sourceByte, uint16_t instance);

status_t dataSink(uint8_t sinkByte, uint16_t instance);

void onError(status_t error);

All callbacks are invoked from IRQ state.

Setup

To initialize the SPI slave driver, first create and fill in the #spi_slave_config_t structure. This structure defines the callbacks and data format settings for the SPI peripheral. The structure is not required after the driver is initialized and can be allocated on the stack.This is an example of a config struct definition:

spi_slave_config_t config = {
        {
            appDataSource,
            appDataSink,
            appErrorHandler,
        },
        kSpiClockPhase_FirstEdge,
        kSpiClockPolarity_ActiveHigh,
        kSpiLsbFirst
    };

---

Data Structure Documentation

struct spi_slave_callbacks_t

Data Fields
spi_status_t(*	dataSource )(uint8_t *sourceByte, uint16_t instance)
	Callback used to get byte to transmit. More...
spi_status_t(*	dataSink )(uint8_t sinkByte, uint16_t instance)
	Callback used to put received byte. More...
void(*	onError )(spi_status_t error)
	Callback used to report an SPI error. More...

Field Documentation

spi_status_t(* spi_slave_callbacks_t::dataSource)(uint8_t *sourceByte, uint16_t instance)

spi_status_t(* spi_slave_callbacks_t::dataSink)(uint8_t sinkByte, uint16_t instance)

void(* spi_slave_callbacks_t::onError)(spi_status_t error)

struct spi_slave_user_config_t

functions used by the SPI slave driver.

Data Fields
spi_slave_callbacks_t	callbacks
	Application callbacks. More...
spi_clock_phase_t	phase
	Clock phase setting. More...
spi_clock_polarity_t	polarity
	Clock polarity setting. More...
spi_shift_direction_t	direction
	Either LSB or MSB first. More...

Field Documentation

spi_slave_callbacks_t spi_slave_user_config_t::callbacks

spi_clock_phase_t spi_slave_user_config_t::phase

spi_clock_polarity_t spi_slave_user_config_t::polarity

spi_shift_direction_t spi_slave_user_config_t::direction

Function Documentation

void spi_slave_init	(	uint32_t	instance,
		const spi_slave_user_config_t *	config
	)

Saves the application callback info, turns on the clock to the module, enables the device, and enables interrupts. Sets the SPI to a slave mode.

Parameters

instance	Instance number of the SPI module.
config	Pointer to slave mode configuration.

void spi_slave_shutdown

(

uint32_t

instance

)

Clears the control register and turns off the clock to the module.

Parameters

instance

Instance number of the SPI module.