Data Structures
struct	i2c_slave_config
	Configuration structure for the I²C slave device. More...

struct	i2c_slave_module
	SERCOM I²C slave driver software device instance structure. More...

struct	i2c_slave_packet
	I²C slave packet for read/write. More...

Enumerations
enum	i2c_slave_address_mode { I2C_SLAVE_ADDRESS_MODE_MASK = SERCOM_I2CS_CTRLB_AMODE(0), I2C_SLAVE_ADDRESS_MODE_TWO_ADDRESSES = SERCOM_I2CS_CTRLB_AMODE(1), I2C_SLAVE_ADDRESS_MODE_RANGE = SERCOM_I2CS_CTRLB_AMODE(2) }
	Enum for the possible address modes. More...

enum	i2c_slave_direction { I2C_SLAVE_DIRECTION_READ, I2C_SLAVE_DIRECTION_WRITE, I2C_SLAVE_DIRECTION_NONE }
	Enum for the direction of a request. More...

enum	i2c_slave_sda_hold_time { I2C_SLAVE_SDA_HOLD_TIME_DISABLED, I2C_SLAVE_SDA_HOLD_TIME_50NS_100NS, I2C_SLAVE_SDA_HOLD_TIME_300NS_600NS, I2C_SLAVE_SDA_HOLD_TIME_400NS_800NS }
	Enum for the possible SDA hold times with respect to the negative edge of SCL. More...

I2C Slave Status Flags
I²C slave status flags, returned by i2c_slave_get_status() and cleared by i2c_slave_clear_status().
#define	I2C_SLAVE_STATUS_ADDRESS_MATCH (1UL << 0)
	Address Match. More...

#define	I2C_SLAVE_STATUS_DATA_READY (1UL << 1)
	Data Ready. More...

#define	I2C_SLAVE_STATUS_STOP_RECEIVED (1UL << 2)
	Stop Received. More...

#define	I2C_SLAVE_STATUS_CLOCK_HOLD (1UL << 3)
	Clock Hold. More...

#define	I2C_SLAVE_STATUS_SCL_LOW_TIMEOUT (1UL << 4)
	SCL Low Timeout. More...

#define	I2C_SLAVE_STATUS_REPEATED_START (1UL << 5)
	Repeated Start. More...

#define	I2C_SLAVE_STATUS_RECEIVED_NACK (1UL << 6)
	Received not acknowledge. More...

#define	I2C_SLAVE_STATUS_COLLISION (1UL << 7)
	Transmit Collision. More...

#define	I2C_SLAVE_STATUS_BUS_ERROR (1UL << 8)
	Bus error. More...

Lock/Unlock
static enum status_code	i2c_slave_lock (struct i2c_slave_module *const module)
	Attempt to get lock on driver instance. More...

static void	i2c_slave_unlock (struct i2c_slave_module *const module)
	Unlock driver instance. More...

Configuration and Initialization
static bool	i2c_slave_is_syncing (const struct i2c_slave_module *const module)
	Returns the synchronization status of the module. More...

static void	i2c_slave_get_config_defaults (struct i2c_slave_config *const config)
	Gets the I²C slave default configurations. More...

enum status_code	i2c_slave_init (struct i2c_slave_module const module, Sercom const hw, const struct i2c_slave_config *const config)
	Initializes the requested I²C hardware module. More...

static void	i2c_slave_enable (const struct i2c_slave_module *const module)
	Enables the I²C module. More...

static void	i2c_slave_disable (const struct i2c_slave_module *const module)
	Disables the I²C module. More...

void	i2c_slave_reset (struct i2c_slave_module *const module)
	Resets the hardware module. More...

Read and Write
enum status_code	i2c_slave_write_packet_wait (struct i2c_slave_module const module, struct i2c_slave_packet const packet)
	Writes a packet to the master. More...

enum status_code	i2c_slave_read_packet_wait (struct i2c_slave_module const module, struct i2c_slave_packet const packet)
	Reads a packet from the master. More...

enum i2c_slave_direction	i2c_slave_get_direction_wait (struct i2c_slave_module *const module)
	Waits for a start condition on the bus. More...

Status Management
uint32_t	i2c_slave_get_status (struct i2c_slave_module *const module)
	Retrieves the current module status. More...

void	i2c_slave_clear_status (struct i2c_slave_module *const module, uint32_t status_flags)
	Clears a module status flag. More...

#define I2C_SLAVE_STATUS_ADDRESS_MATCH (1UL << 0)

Address Match.

Note: Should only be cleared internally by driver.

Referenced by i2c_slave_clear_status(), and i2c_slave_get_status().

#define I2C_SLAVE_STATUS_BUS_ERROR (1UL << 8)

Bus error.

Referenced by i2c_slave_clear_status(), and i2c_slave_get_status().

#define I2C_SLAVE_STATUS_CLOCK_HOLD (1UL << 3)

Clock Hold.

Note: Cannot be cleared, only valid when I2C_SLAVE_STATUS_ADDRESS_MATCH is set.

Referenced by i2c_slave_get_status().

#define I2C_SLAVE_STATUS_COLLISION (1UL << 7)

Transmit Collision.

Referenced by i2c_slave_clear_status(), and i2c_slave_get_status().

#define I2C_SLAVE_STATUS_DATA_READY (1UL << 1)

Data Ready.

Referenced by i2c_slave_clear_status(), and i2c_slave_get_status().

#define I2C_SLAVE_STATUS_RECEIVED_NACK (1UL << 6)

Received not acknowledge.

Note: Cannot be cleared.

Referenced by i2c_slave_get_status().

#define I2C_SLAVE_STATUS_REPEATED_START (1UL << 5)

Repeated Start.

Note: Cannot be cleared, only valid when I2C_SLAVE_STATUS_ADDRESS_MATCH is set.

Referenced by i2c_slave_get_status().

#define I2C_SLAVE_STATUS_SCL_LOW_TIMEOUT (1UL << 4)

SCL Low Timeout.

Referenced by i2c_slave_clear_status(), and i2c_slave_get_status().

#define I2C_SLAVE_STATUS_STOP_RECEIVED (1UL << 2)

Stop Received.

Referenced by i2c_slave_clear_status(), and i2c_slave_get_status().

enum i2c_slave_address_mode

Enum for the possible address modes.

Enumerator
I2C_SLAVE_ADDRESS_MODE_MASK	Address match on address_mask used as a mask to address.
I2C_SLAVE_ADDRESS_MODE_TWO_ADDRESSES	Address math on both address and address_mask.
I2C_SLAVE_ADDRESS_MODE_RANGE	Address match on range of addresses between and including address and address_mask.

enum i2c_slave_direction

Enum for the direction of a request.

Enumerator
I2C_SLAVE_DIRECTION_READ	Read.
I2C_SLAVE_DIRECTION_WRITE	Write.
I2C_SLAVE_DIRECTION_NONE	No direction.

enum i2c_slave_sda_hold_time

Enum for the possible SDA hold times with respect to the negative edge of SCL.

Enumerator
I2C_SLAVE_SDA_HOLD_TIME_DISABLED	SDA hold time disabled.
I2C_SLAVE_SDA_HOLD_TIME_50NS_100NS	SDA hold time 50ns - 100ns.
I2C_SLAVE_SDA_HOLD_TIME_300NS_600NS	SDA hold time 300ns - 600ns.
I2C_SLAVE_SDA_HOLD_TIME_400NS_800NS	SDA hold time 400ns - 800ns.

void i2c_slave_clear_status	(	struct i2c_slave_module *const	module,
		uint32_t	status_flags
	)

Clears a module status flag.

Clears the given status flag of the module.

Note: Not all status flags can be cleared.

Parameters

[in]	module	Pointer to the I²C software device struct
[in]	status_flags	Bit mask of status flags to clear

References Assert, I2C_SLAVE_STATUS_ADDRESS_MATCH, I2C_SLAVE_STATUS_BUS_ERROR, I2C_SLAVE_STATUS_COLLISION, I2C_SLAVE_STATUS_DATA_READY, I2C_SLAVE_STATUS_SCL_LOW_TIMEOUT, and I2C_SLAVE_STATUS_STOP_RECEIVED.

static void i2c_slave_disable ( const struct i2c_slave_module *const module )

inlinestatic

Disables the I²C module.

This will disable the I²C module specified in the provided software module structure.

Parameters

[in] module Pointer to the software module struct

References Assert, and system_interrupt_disable().

Referenced by i2c_slave_reset().

static void i2c_slave_enable ( const struct i2c_slave_module *const module )

inlinestatic

Enables the I²C module.

This will enable the requested I²C module.

Parameters

[in] module Pointer to the software module struct

References Assert, and system_interrupt_enable().

Referenced by configure_i2c().

static void i2c_slave_get_config_defaults ( struct i2c_slave_config *const config )

inlinestatic

Gets the I²C slave default configurations.

This will initialize the configuration structure to known default values.

The default configuration is as follows:

Disable SCL low timeout
300ns - 600ns SDA hold time
Buffer timeout = 65535
Address with mask
Address = 0
Address mask = 0 (one single address)
General call address disabled
Address nack disabled if the interrupt driver is used
GCLK generator 0
Do not run in standby
PINMUX_DEFAULT for SERCOM pads

Those default configuration only available if the device supports it:

Not using 10-bit addressing
Standard-mode and Fast-mode transfer speed
SCL stretch disabled
Slave SCL low extend time-out disabled

Parameters

[out] config Pointer to configuration structure to be initialized

References i2c_slave_config::address, i2c_slave_config::address_mask, i2c_slave_config::address_mode, Assert, i2c_slave_config::buffer_timeout, i2c_slave_config::enable_general_call_address, i2c_slave_config::enable_scl_low_timeout, GCLK_GENERATOR_0, i2c_slave_config::generator_source, I2C_SLAVE_ADDRESS_MODE_MASK, I2C_SLAVE_SDA_HOLD_TIME_300NS_600NS, PINMUX_DEFAULT, i2c_slave_config::pinmux_pad0, i2c_slave_config::pinmux_pad1, i2c_slave_config::run_in_standby, i2c_slave_config::scl_low_timeout, and i2c_slave_config::sda_hold_time.

Referenced by configure_i2c().

enum i2c_slave_direction i2c_slave_get_direction_wait ( struct i2c_slave_module *const module )

Waits for a start condition on the bus.

Note: This function is only available for 7-bit slave addressing.

Waits for the master to issue a start condition on the bus.

Note: This function does not check for errors in the last transfer, this will be discovered when reading or writing.

Parameters

[in] module Pointer to software module structure

Returns: Direction of the current transfer, when in slave mode.

Return values

I2C_SLAVE_DIRECTION_NONE	No request from master within timeout period
I2C_SLAVE_DIRECTION_READ	Write request from master
I2C_SLAVE_DIRECTION_WRITE	Read request from master

References _i2c_slave_wait_for_bus(), Assert, I2C_SLAVE_DIRECTION_NONE, I2C_SLAVE_DIRECTION_READ, I2C_SLAVE_DIRECTION_WRITE, and STATUS_OK.

uint32_t i2c_slave_get_status ( struct i2c_slave_module *const module )

Retrieves the current module status.

Checks the status of the module and returns it as a bitmask of status flags.

Parameters

[in] module Pointer to the I²C slave software device struct

Returns: Bitmask of status flags.

Return values

I2C_SLAVE_STATUS_ADDRESS_MATCH	A valid address has been received
I2C_SLAVE_STATUS_DATA_READY	A I²C slave byte transmission is successfully completed
I2C_SLAVE_STATUS_STOP_RECEIVED	A stop condition is detected for a transaction being processed
I2C_SLAVE_STATUS_CLOCK_HOLD	The slave is holding the SCL line low
I2C_SLAVE_STATUS_SCL_LOW_TIMEOUT	An SCL low time-out has occurred
I2C_SLAVE_STATUS_REPEATED_START	Indicates a repeated start, only valid if I2C_SLAVE_STATUS_ADDRESS_MATCH is set
I2C_SLAVE_STATUS_RECEIVED_NACK	The last data packet sent was not acknowledged
I2C_SLAVE_STATUS_COLLISION	The I²C slave was not able to transmit a high data or NACK bit
I2C_SLAVE_STATUS_BUS_ERROR	An illegal bus condition has occurred on the bus

References Assert, I2C_SLAVE_STATUS_ADDRESS_MATCH, I2C_SLAVE_STATUS_BUS_ERROR, I2C_SLAVE_STATUS_CLOCK_HOLD, I2C_SLAVE_STATUS_COLLISION, I2C_SLAVE_STATUS_DATA_READY, I2C_SLAVE_STATUS_RECEIVED_NACK, I2C_SLAVE_STATUS_REPEATED_START, I2C_SLAVE_STATUS_SCL_LOW_TIMEOUT, and I2C_SLAVE_STATUS_STOP_RECEIVED.

enum status_code i2c_slave_init	(	struct i2c_slave_module *const	module,
		Sercom *const	hw,
		const struct i2c_slave_config *const	config
	)

Initializes the requested I²C hardware module.

Initializes the SERCOM I²C slave device requested and sets the provided software module struct. Run this function before any further use of the driver.

Parameters

[out]	module	Pointer to software module struct
[in]	hw	Pointer to the hardware instance
[in]	config	Pointer to the configuration struct

Returns: Status of initialization.

Return values

STATUS_OK	Module initiated correctly
STATUS_ERR_DENIED	If module is enabled
STATUS_BUSY	If module is busy resetting
STATUS_ERR_ALREADY_INITIALIZED	If setting other GCLK generator than previously set

References _i2c_slave_set_config(), _sercom_get_sercom_inst_index(), Assert, i2c_slave_config::generator_source, sercom_set_gclk_generator(), system_gclk_chan_config::source_generator, STATUS_BUSY, STATUS_ERR_DENIED, system_apb_clock_set_mask(), SYSTEM_CLOCK_APB_APBC, system_gclk_chan_enable(), system_gclk_chan_get_config_defaults(), and system_gclk_chan_set_config().

Referenced by configure_i2c().

static bool i2c_slave_is_syncing ( const struct i2c_slave_module *const module )

inlinestatic

Returns the synchronization status of the module.

Parameters

[out] module Pointer to software module structure

Returns: Status of the synchronization.

Return values

true	Module is busy synchronizing
false	Module is not synchronizing

References Assert.

static enum status_code i2c_slave_lock ( struct i2c_slave_module *const module )

inlinestatic

Attempt to get lock on driver instance.

This function checks the instance's lock, which indicates whether or not it is currently in use, and sets the lock if it was not already set.

The purpose of this is to enable exclusive access to driver instances, so that, e.g., transactions by different services will not interfere with each other.

Parameters

[in,out] module Pointer to the driver instance to lock

Return values

STATUS_OK	If the module was locked
STATUS_BUSY	If the module was already locked

References STATUS_BUSY, STATUS_OK, system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

enum status_code i2c_slave_read_packet_wait	(	struct i2c_slave_module *const	module,
		struct i2c_slave_packet *const	packet
	)

Reads a packet from the master.

Reads a packet from the master. This will wait for the master to issue a request.

Parameters

[in]	module	Pointer to software module structure
[out]	packet	Packet to read from master

Returns: Status of packet read.

Return values

STATUS_OK	Packet was read successfully
STATUS_ABORTED	Master sent stop condition or repeated start before specified length of bytes was received
STATUS_ERR_IO	There was an error in the previous transfer
STATUS_ERR_DENIED	Start condition not received, another interrupt flag is set
STATUS_ERR_INVALID_ARG	Invalid argument(s) was provided
STATUS_ERR_BUSY	The I²C module is busy with a job
STATUS_ERR_BAD_FORMAT	Master wants to read data
STATUS_ERR_ERR_OVERFLOW	Last byte received overflows buffer

References _i2c_slave_wait_for_bus(), Assert, i2c_slave_packet::data, i2c_slave_packet::data_length, STATUS_ABORTED, STATUS_BUSY, STATUS_ERR_BAD_FORMAT, STATUS_ERR_DENIED, STATUS_ERR_INVALID_ARG, STATUS_ERR_IO, and STATUS_OK.

Referenced by fetch_data(), and get_length().

void i2c_slave_reset ( struct i2c_slave_module *const module )

Resets the hardware module.

This will reset the module to hardware defaults.

Parameters

[in,out] module Pointer to software module structure

References Assert, i2c_slave_disable(), system_interrupt_clear_pending(), system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

static void i2c_slave_unlock ( struct i2c_slave_module *const module )

inlinestatic

Unlock driver instance.

This function clears the instance lock, indicating that it is available for use.

Parameters

[in,out] module Pointer to the driver instance to lock

Return values

STATUS_OK	If the module was locked
STATUS_BUSY	If the module was already locked

enum status_code i2c_slave_write_packet_wait	(	struct i2c_slave_module *const	module,
		struct i2c_slave_packet *const	packet
	)

Writes a packet to the master.

Writes a packet to the master. This will wait for the master to issue a request.

Parameters

[in]	module	Pointer to software module structure
[in]	packet	Packet to write to master

Returns: Status of packet write.

Return values

STATUS_OK	Packet was written successfully
STATUS_ERR_DENIED	Start condition not received, another interrupt flag is set
STATUS_ERR_IO	There was an error in the previous transfer
STATUS_ERR_BAD_FORMAT	Master wants to write data
STATUS_ERR_INVALID_ARG	Invalid argument(s) was provided
STATUS_ERR_BUSY	The I²C module is busy with a job
STATUS_ERR_ERR_OVERFLOW	Master NACKed before entire packet was transferred
STATUS_ERR_TIMEOUT	No response was given within the timeout period

References _i2c_slave_wait_for_bus(), Assert, i2c_slave_packet::data, i2c_slave_packet::data_length, STATUS_BUSY, STATUS_ERR_BAD_FORMAT, STATUS_ERR_DENIED, STATUS_ERR_INVALID_ARG, STATUS_ERR_IO, STATUS_ERR_OVERFLOW, STATUS_ERR_TIMEOUT, and STATUS_OK.

Referenced by send_ack().

Microchip® Advanced Software Framework

Data Structures

Enumerations

I2C Slave Status Flags

Lock/Unlock

Configuration and Initialization

Read and Write

Status Management