Overview

The MCUXpresso SDK provides a peripheral driver for I2C master function using Flexible I/O module of MCUXpresso SDK devices.

The FlexIO I2C master driver includes functional APIs and transactional APIs.

Functional APIs target low level APIs. Functional APIs can be used for the FlexIO I2C master initialization/configuration/operation for the optimization/customization purpose. Using the functional APIs requires the knowledge of the FlexIO I2C master peripheral and how to organize functional APIs to meet the application requirements. The FlexIO I2C master functional operation groups provide the functional APIs set.

Transactional APIs target high-level APIs. The transactional APIs can be used to enable the peripheral quickly and also in the application if the code size and performance of transactional APIs satisfy the requirements. If the code size and performance are critical requirements, see the transactional API implementation and write custom code using the functional APIs or accessing the hardware registers.

Transactional APIs support an asynchronous transfer. This means that the functions FLEXIO_I2C_MasterTransferNonBlocking() set up the interrupt non-blocking transfer. When the transfer completes, the upper layer is notified through a callback function with the kStatus_Success status.

Typical use case

FlexIO I2C master transfer using an interrupt method

flexio_i2c_master_handle_t g_m_handle;
flexio_i2c_master_config_t masterConfig;
flexio_i2c_master_transfer_t masterXfer;
volatile bool completionFlag = false;
const uint8_t sendData[] = [......];
FLEXIO_I2C_Type i2cDev;
void FLEXIO_I2C_MasterCallback(FLEXIO_I2C_Type *base, status_t status, void *userData)
{
    userData = userData;
    if (kStatus_Success == status)
    {
        completionFlag = true;
    }
}
void main(void)
{
    //...
    FLEXIO_I2C_MasterGetDefaultConfig(&masterConfig);
    FLEXIO_I2C_MasterInit(&i2cDev, &user_config);
    FLEXIO_I2C_MasterTransferCreateHandle(&i2cDev, &g_m_handle, FLEXIO_I2C_MasterCallback, NULL);
    // Prepares to send.
    masterXfer.slaveAddress = g_accel_address[0];
    masterXfer.direction = kI2C_Read;
    masterXfer.subaddress = &who_am_i_reg;
    masterXfer.subaddressSize = 1;
    masterXfer.data = &who_am_i_value;
    masterXfer.dataSize = 1;
    masterXfer.flags = kI2C_TransferDefaultFlag;
    // Sends out.
    FLEXIO_I2C_MasterTransferNonBlocking(&i2cDev, &g_m_handle, &masterXfer);
    // Wait for sending is complete.
    while (!completionFlag)
    {
    }
    // ...
}

Data Structures
struct	FLEXIO_I2C_Type
	Define FlexIO I2C master access structure typedef. More...

struct	flexio_i2c_master_config_t
	Define FlexIO I2C master user configuration structure. More...

struct	flexio_i2c_master_transfer_t
	Define FlexIO I2C master transfer structure. More...

struct	flexio_i2c_master_handle_t
	Define FlexIO I2C master handle structure. More...

Typedefs
typedef void(*	flexio_i2c_master_transfer_callback_t )(FLEXIO_I2C_Type base, flexio_i2c_master_handle_t handle, status_t status, void *userData)
	FlexIO I2C master transfer callback typedef. More...

Enumerations
enum	_flexio_i2c_status { kStatus_FLEXIO_I2C_Busy = MAKE_STATUS(kStatusGroup_FLEXIO_I2C, 0), kStatus_FLEXIO_I2C_Idle = MAKE_STATUS(kStatusGroup_FLEXIO_I2C, 1), kStatus_FLEXIO_I2C_Nak = MAKE_STATUS(kStatusGroup_FLEXIO_I2C, 2) }
	FlexIO I2C transfer status. More...

enum	_flexio_i2c_master_interrupt { kFLEXIO_I2C_TxEmptyInterruptEnable = 0x1U, kFLEXIO_I2C_RxFullInterruptEnable = 0x2U }
	Define FlexIO I2C master interrupt mask. More...

enum	_flexio_i2c_master_status_flags { kFLEXIO_I2C_TxEmptyFlag = 0x1U, kFLEXIO_I2C_RxFullFlag = 0x2U, kFLEXIO_I2C_ReceiveNakFlag = 0x4U }
	Define FlexIO I2C master status mask. More...

enum	flexio_i2c_direction_t { kFLEXIO_I2C_Write = 0x0U, kFLEXIO_I2C_Read = 0x1U }
	Direction of master transfer. More...

Driver version
#define	FSL_FLEXIO_I2C_MASTER_DRIVER_VERSION (MAKE_VERSION(2, 1, 2))
	FlexIO I2C master driver version 2.1.2. More...

Initialization and deinitialization
status_t	FLEXIO_I2C_MasterInit (FLEXIO_I2C_Type base, flexio_i2c_master_config_t masterConfig, uint32_t srcClock_Hz)
	Ungates the FlexIO clock, resets the FlexIO module, and configures the FlexIO I2C hardware configuration. More...

void	FLEXIO_I2C_MasterDeinit (FLEXIO_I2C_Type *base)
	De-initializes the FlexIO I2C master peripheral. More...

void	FLEXIO_I2C_MasterGetDefaultConfig (flexio_i2c_master_config_t *masterConfig)
	Gets the default configuration to configure the FlexIO module. More...

static void	FLEXIO_I2C_MasterEnable (FLEXIO_I2C_Type *base, bool enable)
	Enables/disables the FlexIO module operation. More...

Status
uint32_t	FLEXIO_I2C_MasterGetStatusFlags (FLEXIO_I2C_Type *base)
	Gets the FlexIO I2C master status flags. More...

void	FLEXIO_I2C_MasterClearStatusFlags (FLEXIO_I2C_Type *base, uint32_t mask)
	Clears the FlexIO I2C master status flags. More...

Interrupts
void	FLEXIO_I2C_MasterEnableInterrupts (FLEXIO_I2C_Type *base, uint32_t mask)
	Enables the FlexIO i2c master interrupt requests. More...

void	FLEXIO_I2C_MasterDisableInterrupts (FLEXIO_I2C_Type *base, uint32_t mask)
	Disables the FlexIO I2C master interrupt requests. More...

Bus Operations
void	FLEXIO_I2C_MasterSetBaudRate (FLEXIO_I2C_Type *base, uint32_t baudRate_Bps, uint32_t srcClock_Hz)
	Sets the FlexIO I2C master transfer baudrate. More...

void	FLEXIO_I2C_MasterStart (FLEXIO_I2C_Type *base, uint8_t address, flexio_i2c_direction_t direction)
	Sends START + 7-bit address to the bus. More...

void	FLEXIO_I2C_MasterStop (FLEXIO_I2C_Type *base)
	Sends the stop signal on the bus. More...

void	FLEXIO_I2C_MasterRepeatedStart (FLEXIO_I2C_Type *base)
	Sends the repeated start signal on the bus. More...

void	FLEXIO_I2C_MasterAbortStop (FLEXIO_I2C_Type *base)
	Sends the stop signal when transfer is still on-going. More...

void	FLEXIO_I2C_MasterEnableAck (FLEXIO_I2C_Type *base, bool enable)
	Configures the sent ACK/NAK for the following byte. More...

status_t	FLEXIO_I2C_MasterSetTransferCount (FLEXIO_I2C_Type *base, uint8_t count)
	Sets the number of bytes to be transferred from a start signal to a stop signal. More...

static void	FLEXIO_I2C_MasterWriteByte (FLEXIO_I2C_Type *base, uint32_t data)
	Writes one byte of data to the I2C bus. More...

static uint8_t	FLEXIO_I2C_MasterReadByte (FLEXIO_I2C_Type *base)
	Reads one byte of data from the I2C bus. More...

status_t	FLEXIO_I2C_MasterWriteBlocking (FLEXIO_I2C_Type base, const uint8_t txBuff, uint8_t txSize)
	Sends a buffer of data in bytes. More...

void	FLEXIO_I2C_MasterReadBlocking (FLEXIO_I2C_Type base, uint8_t rxBuff, uint8_t rxSize)
	Receives a buffer of bytes. More...

status_t	FLEXIO_I2C_MasterTransferBlocking (FLEXIO_I2C_Type base, flexio_i2c_master_transfer_t xfer)
	Performs a master polling transfer on the I2C bus. More...

Transactional
status_t	FLEXIO_I2C_MasterTransferCreateHandle (FLEXIO_I2C_Type base, flexio_i2c_master_handle_t handle, flexio_i2c_master_transfer_callback_t callback, void *userData)
	Initializes the I2C handle which is used in transactional functions. More...

status_t	FLEXIO_I2C_MasterTransferNonBlocking (FLEXIO_I2C_Type base, flexio_i2c_master_handle_t handle, flexio_i2c_master_transfer_t *xfer)
	Performs a master interrupt non-blocking transfer on the I2C bus. More...

status_t	FLEXIO_I2C_MasterTransferGetCount (FLEXIO_I2C_Type base, flexio_i2c_master_handle_t handle, size_t *count)
	Gets the master transfer status during a interrupt non-blocking transfer. More...

void	FLEXIO_I2C_MasterTransferAbort (FLEXIO_I2C_Type base, flexio_i2c_master_handle_t handle)
	Aborts an interrupt non-blocking transfer early. More...

void	FLEXIO_I2C_MasterTransferHandleIRQ (void i2cType, void i2cHandle)
	Master interrupt handler. More...

Data Structure Documentation

struct FLEXIO_I2C_Type

Data Fields
FLEXIO_Type *	flexioBase
	FlexIO base pointer. More...

uint8_t	SDAPinIndex
	Pin select for I2C SDA. More...

uint8_t	SCLPinIndex
	Pin select for I2C SCL. More...

uint8_t	shifterIndex [2]
	Shifter index used in FlexIO I2C. More...

uint8_t	timerIndex [2]
	Timer index used in FlexIO I2C. More...

Field Documentation

FLEXIO_Type* FLEXIO_I2C_Type::flexioBase

uint8_t FLEXIO_I2C_Type::SDAPinIndex

uint8_t FLEXIO_I2C_Type::SCLPinIndex

uint8_t FLEXIO_I2C_Type::shifterIndex[2]

uint8_t FLEXIO_I2C_Type::timerIndex[2]

struct flexio_i2c_master_config_t

Data Fields
bool	enableMaster
	Enables the FlexIO I2C peripheral at initialization time. More...

bool	enableInDoze
	Enable/disable FlexIO operation in doze mode. More...

bool	enableInDebug
	Enable/disable FlexIO operation in debug mode. More...

bool	enableFastAccess
	Enable/disable fast access to FlexIO registers, fast access requires the FlexIO clock to be at least twice the frequency of the bus clock. More...

uint32_t	baudRate_Bps
	Baud rate in Bps. More...

Field Documentation

bool flexio_i2c_master_config_t::enableMaster

bool flexio_i2c_master_config_t::enableInDoze

bool flexio_i2c_master_config_t::enableInDebug

bool flexio_i2c_master_config_t::enableFastAccess

uint32_t flexio_i2c_master_config_t::baudRate_Bps

struct flexio_i2c_master_transfer_t

Data Fields
uint32_t	flags
	Transfer flag which controls the transfer, reserved for FlexIO I2C. More...

uint8_t	slaveAddress
	7-bit slave address. More...

flexio_i2c_direction_t	direction
	Transfer direction, read or write. More...

uint32_t	subaddress
	Sub address. More...

uint8_t	subaddressSize
	Size of command buffer. More...

uint8_t volatile *	data
	Transfer buffer. More...

volatile size_t	dataSize
	Transfer size. More...

Field Documentation

uint32_t flexio_i2c_master_transfer_t::flags

uint8_t flexio_i2c_master_transfer_t::slaveAddress

flexio_i2c_direction_t flexio_i2c_master_transfer_t::direction

uint32_t flexio_i2c_master_transfer_t::subaddress

Transferred MSB first.

uint8_t flexio_i2c_master_transfer_t::subaddressSize

uint8_t volatile* flexio_i2c_master_transfer_t::data

volatile size_t flexio_i2c_master_transfer_t::dataSize

struct _flexio_i2c_master_handle

FlexIO I2C master handle typedef.

Data Fields
flexio_i2c_master_transfer_t	transfer
	FlexIO I2C master transfer copy. More...

size_t	transferSize
	Total bytes to be transferred. More...

uint8_t	state
	Transfer state maintained during transfer. More...

flexio_i2c_master_transfer_callback_t	completionCallback
	Callback function called at transfer event. More...

void *	userData
	Callback parameter passed to callback function. More...

Field Documentation

flexio_i2c_master_transfer_t flexio_i2c_master_handle_t::transfer

size_t flexio_i2c_master_handle_t::transferSize

uint8_t flexio_i2c_master_handle_t::state

flexio_i2c_master_transfer_callback_t flexio_i2c_master_handle_t::completionCallback

Callback function called at transfer event.

void* flexio_i2c_master_handle_t::userData

Macro Definition Documentation

#define FSL_FLEXIO_I2C_MASTER_DRIVER_VERSION (MAKE_VERSION(2, 1, 2))

Typedef Documentation

typedef void(* flexio_i2c_master_transfer_callback_t)(FLEXIO_I2C_Type *base, flexio_i2c_master_handle_t *handle, status_t status, void *userData)

Enumeration Type Documentation

enum _flexio_i2c_status

Enumerator
kStatus_FLEXIO_I2C_Busy	I2C is busy doing transfer.
kStatus_FLEXIO_I2C_Idle	I2C is busy doing transfer.
kStatus_FLEXIO_I2C_Nak	NAK received during transfer.

enum _flexio_i2c_master_interrupt

Enumerator
kFLEXIO_I2C_TxEmptyInterruptEnable	Tx buffer empty interrupt enable.
kFLEXIO_I2C_RxFullInterruptEnable	Rx buffer full interrupt enable.

enum _flexio_i2c_master_status_flags

Enumerator
kFLEXIO_I2C_TxEmptyFlag	Tx shifter empty flag.
kFLEXIO_I2C_RxFullFlag	Rx shifter full/Transfer complete flag.
kFLEXIO_I2C_ReceiveNakFlag	Receive NAK flag.

enum flexio_i2c_direction_t

Enumerator
kFLEXIO_I2C_Write	Master send to slave.
kFLEXIO_I2C_Read	Master receive from slave.

Function Documentation

status_t FLEXIO_I2C_MasterInit	(	FLEXIO_I2C_Type *	base,
		flexio_i2c_master_config_t *	masterConfig,
		uint32_t	srcClock_Hz
	)

Example

FLEXIO_I2C_Type base = {
.flexioBase = FLEXIO,
.SDAPinIndex = 0,
.SCLPinIndex = 1,
.shifterIndex = {0,1},
.timerIndex = {0,1}
};
flexio_i2c_master_config_t config = {
.enableInDoze = false,
.enableInDebug = true,
.enableFastAccess = false,
.baudRate_Bps = 100000
};
FLEXIO_I2C_MasterInit(base, &config, srcClock_Hz);

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
masterConfig	Pointer to flexio_i2c_master_config_t structure.
srcClock_Hz	FlexIO source clock in Hz.

Return values

kStatus_Success	Initialization successful
kStatus_InvalidArgument	The source clock exceed upper range limitation

void FLEXIO_I2C_MasterDeinit ( FLEXIO_I2C_Type * base )

Calling this API gates the FlexIO clock and the FlexIO I2C master module can't work unless the FLEXIO_I2C_MasterInit is called.

Parameters

base	pointer to FLEXIO_I2C_Type structure.

void FLEXIO_I2C_MasterGetDefaultConfig ( flexio_i2c_master_config_t * masterConfig )

The configuration can be used directly for calling the FLEXIO_I2C_MasterInit().

Example:

flexio_i2c_master_config_t config;

FLEXIO_I2C_MasterGetDefaultConfig(&config);

Parameters

masterConfig Pointer to flexio_i2c_master_config_t structure.

static void FLEXIO_I2C_MasterEnable	(	FLEXIO_I2C_Type *	base,
		bool	enable
	)

inlinestatic

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
enable	Pass true to enable module, false to disable module.

uint32_t FLEXIO_I2C_MasterGetStatusFlags ( FLEXIO_I2C_Type * base )

Parameters

base	Pointer to FLEXIO_I2C_Type structure

Returns: Status flag, use status flag to AND _flexio_i2c_master_status_flags can get the related status.

void FLEXIO_I2C_MasterClearStatusFlags	(	FLEXIO_I2C_Type *	base,
		uint32_t	mask
	)

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
mask	Status flag. The parameter can be any combination of the following values: kFLEXIO_I2C_RxFullFlag kFLEXIO_I2C_ReceiveNakFlag

void FLEXIO_I2C_MasterEnableInterrupts	(	FLEXIO_I2C_Type *	base,
		uint32_t	mask
	)

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
mask	Interrupt source. Currently only one interrupt request source: kFLEXIO_I2C_TransferCompleteInterruptEnable

void FLEXIO_I2C_MasterDisableInterrupts	(	FLEXIO_I2C_Type *	base,
		uint32_t	mask
	)

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
mask	Interrupt source.

void FLEXIO_I2C_MasterSetBaudRate	(	FLEXIO_I2C_Type *	base,
		uint32_t	baudRate_Bps,
		uint32_t	srcClock_Hz
	)

Parameters

base	Pointer to FLEXIO_I2C_Type structure
baudRate_Bps	the baud rate value in HZ
srcClock_Hz	source clock in HZ

void FLEXIO_I2C_MasterStart	(	FLEXIO_I2C_Type *	base,
		uint8_t	address,
		flexio_i2c_direction_t	direction
	)

Note: This API should be called when the transfer configuration is ready to send a START signal and 7-bit address to the bus. This is a non-blocking API, which returns directly after the address is put into the data register but the address transfer is not finished on the bus. Ensure that the kFLEXIO_I2C_RxFullFlag status is asserted before calling this API.

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
address	7-bit address.
direction	transfer direction. This parameter is one of the values in flexio_i2c_direction_t: kFLEXIO_I2C_Write: Transmit kFLEXIO_I2C_Read: Receive

void FLEXIO_I2C_MasterStop ( FLEXIO_I2C_Type * base )

Parameters

base	Pointer to FLEXIO_I2C_Type structure.

void FLEXIO_I2C_MasterRepeatedStart ( FLEXIO_I2C_Type * base )

Parameters

base	Pointer to FLEXIO_I2C_Type structure.

void FLEXIO_I2C_MasterAbortStop ( FLEXIO_I2C_Type * base )

Parameters

base	Pointer to FLEXIO_I2C_Type structure.

void FLEXIO_I2C_MasterEnableAck	(	FLEXIO_I2C_Type *	base,
		bool	enable
	)

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
enable	True to configure send ACK, false configure to send NAK.

status_t FLEXIO_I2C_MasterSetTransferCount	(	FLEXIO_I2C_Type *	base,
		uint8_t	count
	)

Note: Call this API before a transfer begins because the timer generates a number of clocks according to the number of bytes that need to be transferred.

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
count	Number of bytes need to be transferred from a start signal to a re-start/stop signal

Return values

kStatus_Success	Successfully configured the count.
kStatus_InvalidArgument	Input argument is invalid.

static void FLEXIO_I2C_MasterWriteByte	(	FLEXIO_I2C_Type *	base,
		uint32_t	data
	)

inlinestatic

Note: This is a non-blocking API, which returns directly after the data is put into the data register but the data transfer is not finished on the bus. Ensure that the TxEmptyFlag is asserted before calling this API.

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
data	a byte of data.

static uint8_t FLEXIO_I2C_MasterReadByte ( FLEXIO_I2C_Type * base )

inlinestatic

Note: This is a non-blocking API, which returns directly after the data is read from the data register. Ensure that the data is ready in the register.

Parameters

base	Pointer to FLEXIO_I2C_Type structure.

Returns: data byte read.

status_t FLEXIO_I2C_MasterWriteBlocking	(	FLEXIO_I2C_Type *	base,
		const uint8_t *	txBuff,
		uint8_t	txSize
	)

Note: This function blocks via polling until all bytes have been sent.

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
txBuff	The data bytes to send.
txSize	The number of data bytes to send.

Return values

kStatus_Success	Successfully write data.
kStatus_FLEXIO_I2C_Nak	Receive NAK during writing data.

void FLEXIO_I2C_MasterReadBlocking	(	FLEXIO_I2C_Type *	base,
		uint8_t *	rxBuff,
		uint8_t	rxSize
	)

Note: This function blocks via polling until all bytes have been received.

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
rxBuff	The buffer to store the received bytes.
rxSize	The number of data bytes to be received.

status_t FLEXIO_I2C_MasterTransferBlocking	(	FLEXIO_I2C_Type *	base,
		flexio_i2c_master_transfer_t *	xfer
	)

Note: The API does not return until the transfer succeeds or fails due to receiving NAK.

Parameters

base	pointer to FLEXIO_I2C_Type structure.
xfer	pointer to flexio_i2c_master_transfer_t structure.

Returns: status of status_t.

status_t FLEXIO_I2C_MasterTransferCreateHandle	(	FLEXIO_I2C_Type *	base,
		flexio_i2c_master_handle_t *	handle,
		flexio_i2c_master_transfer_callback_t	callback,
		void *	userData
	)

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
handle	Pointer to flexio_i2c_master_handle_t structure to store the transfer state.
callback	Pointer to user callback function.
userData	User param passed to the callback function.

Return values

kStatus_Success	Successfully create the handle.
kStatus_OutOfRange	The FlexIO type/handle/isr table out of range.

status_t FLEXIO_I2C_MasterTransferNonBlocking	(	FLEXIO_I2C_Type *	base,
		flexio_i2c_master_handle_t *	handle,
		flexio_i2c_master_transfer_t *	xfer
	)

Note: The API returns immediately after the transfer initiates. Call FLEXIO_I2C_MasterGetTransferCount to poll the transfer status to check whether the transfer is finished. If the return status is not kStatus_FLEXIO_I2C_Busy, the transfer is finished.

Parameters

base	Pointer to FLEXIO_I2C_Type structure
handle	Pointer to flexio_i2c_master_handle_t structure which stores the transfer state
xfer	pointer to flexio_i2c_master_transfer_t structure

Return values

kStatus_Success	Successfully start a transfer.
kStatus_FLEXIO_I2C_Busy	FlexIO I2C is not idle, is running another transfer.

status_t FLEXIO_I2C_MasterTransferGetCount	(	FLEXIO_I2C_Type *	base,
		flexio_i2c_master_handle_t *	handle,
		size_t *	count
	)

Parameters

base	Pointer to FLEXIO_I2C_Type structure.
handle	Pointer to flexio_i2c_master_handle_t structure which stores the transfer state.
count	Number of bytes transferred so far by the non-blocking transaction.

Return values

kStatus_InvalidArgument	count is Invalid.
kStatus_Success	Successfully return the count.

void FLEXIO_I2C_MasterTransferAbort	(	FLEXIO_I2C_Type *	base,
		flexio_i2c_master_handle_t *	handle
	)

Note: This API can be called at any time when an interrupt non-blocking transfer initiates to abort the transfer early.

Parameters

base	Pointer to FLEXIO_I2C_Type structure
handle	Pointer to flexio_i2c_master_handle_t structure which stores the transfer state

void FLEXIO_I2C_MasterTransferHandleIRQ	(	void *	i2cType,
		void *	i2cHandle
	)

Parameters

i2cType	Pointer to FLEXIO_I2C_Type structure
i2cHandle	Pointer to flexio_i2c_master_transfer_t structure

Overview

Typical use case

FlexIO I2C master transfer using an interrupt method

Data Structures

Typedefs

Enumerations

Driver version

Initialization and deinitialization

Status

Interrupts

Bus Operations

Transactional

Data Structure Documentation

Data Fields

Field Documentation

Data Fields

Field Documentation

Data Fields

Field Documentation

Data Fields

Field Documentation

Macro Definition Documentation

Typedef Documentation

Enumeration Type Documentation

Function Documentation