Overview

The KSDK provides a peripheral driver for the Low Power UART (LPUART) module of Kinetis devices.

Typical use case

LPUART Operation

uint8_t ch;
LPUART_GetDefaultConfig(&user_config);
user_config.baudRate = 115200U;
LPUART_Init(LPUART1,&user_config,120000000U);
LPUART_SendDataPolling(LPUART1, txbuff, sizeof(txbuff));
while(1)
{
    LPUART_ReceiveDataPolling(LPUART1,&ch, 1);
    LPUART_SendDataPolling(LPUART1, &ch, 1);
}

Data Structures
struct	lpuart_config_t
	LPUART configure structure. More...

struct	lpuart_transfer_t
	LPUART transfer structure. More...

struct	lpuart_handle_t
	LPUART handle structure. More...

Typedefs
typedef void(*	lpuart_transfer_callback_t )(LPUART_Type base, lpuart_handle_t handle, status_t status, void *userData)
	LPUART transfer callback function. More...

Enumerations
enum	_lpuart_status { kStatus_LPUART_TxBusy = MAKE_STATUS(kStatusGroup_LPUART, 0), kStatus_LPUART_RxBusy = MAKE_STATUS(kStatusGroup_LPUART, 1), kStatus_LPUART_TxIdle = MAKE_STATUS(kStatusGroup_LPUART, 2), kStatus_LPUART_RxIdle = MAKE_STATUS(kStatusGroup_LPUART, 3), kStatus_LPUART_TxWatermarkTooLarge = MAKE_STATUS(kStatusGroup_LPUART, 4), kStatus_LPUART_RxWatermarkTooLarge = MAKE_STATUS(kStatusGroup_LPUART, 5), kStatus_LPUART_FlagCannotClearManually, kStatus_LPUART_Error = MAKE_STATUS(kStatusGroup_LPUART, 7), kStatus_LPUART_RxRingBufferOverrun, kStatus_LPUART_RxHardwareOverrun = MAKE_STATUS(kStatusGroup_LPUART, 9), kStatus_LPUART_NoiseError = MAKE_STATUS(kStatusGroup_LPUART, 10), kStatus_LPUART_FramingError = MAKE_STATUS(kStatusGroup_LPUART, 11), kStatus_LPUART_ParityError = MAKE_STATUS(kStatusGroup_LPUART, 12), kStatus_LPUART_BaudrateNotSupport }
	Error codes for the LPUART driver. More...

enum	lpuart_parity_mode_t { kLPUART_ParityDisabled = 0x0U, kLPUART_ParityEven = 0x2U, kLPUART_ParityOdd = 0x3U }
	LPUART parity mode. More...

enum	lpuart_data_bits_t { kLPUART_EightDataBits = 0x0U }
	LPUART data bits count. More...

enum	lpuart_stop_bit_count_t { kLPUART_OneStopBit = 0U, kLPUART_TwoStopBit = 1U }
	LPUART stop bit count. More...

enum	_lpuart_interrupt_enable { kLPUART_RxActiveEdgeInterruptEnable = (LPUART_BAUD_RXEDGIE_MASK >> 8), kLPUART_TxDataRegEmptyInterruptEnable = (LPUART_CTRL_TIE_MASK), kLPUART_TransmissionCompleteInterruptEnable = (LPUART_CTRL_TCIE_MASK), kLPUART_RxDataRegFullInterruptEnable = (LPUART_CTRL_RIE_MASK), kLPUART_IdleLineInterruptEnable = (LPUART_CTRL_ILIE_MASK), kLPUART_RxOverrunInterruptEnable = (LPUART_CTRL_ORIE_MASK), kLPUART_NoiseErrorInterruptEnable = (LPUART_CTRL_NEIE_MASK), kLPUART_FramingErrorInterruptEnable = (LPUART_CTRL_FEIE_MASK), kLPUART_ParityErrorInterruptEnable = (LPUART_CTRL_PEIE_MASK) }
	LPUART interrupt configuration structure, default settings all disabled. More...

enum	_lpuart_flags { kLPUART_TxDataRegEmptyFlag, kLPUART_TransmissionCompleteFlag, kLPUART_RxDataRegFullFlag, kLPUART_IdleLineFlag = (LPUART_STAT_IDLE_MASK), kLPUART_RxOverrunFlag = (LPUART_STAT_OR_MASK), kLPUART_NoiseErrorFlag = (LPUART_STAT_NF_MASK), kLPUART_FramingErrorFlag, kLPUART_ParityErrorFlag = (LPUART_STAT_PF_MASK), kLPUART_RxActiveEdgeFlag, kLPUART_RxActiveFlag }
	LPUART status flags. More...

Driver version
#define	FSL_LPUART_DRIVER_VERSION (MAKE_VERSION(2, 2, 1))
	LPUART driver version 2.2.1. More...

Initialization and deinitialization
status_t	LPUART_Init (LPUART_Type base, const lpuart_config_t config, uint32_t srcClock_Hz)
	Initializes an LPUART instance with the user configuration structure and the peripheral clock. More...

void	LPUART_Deinit (LPUART_Type *base)
	Deinitializes a LPUART instance. More...

void	LPUART_GetDefaultConfig (lpuart_config_t *config)
	Gets the default configuration structure. More...

status_t	LPUART_SetBaudRate (LPUART_Type *base, uint32_t baudRate_Bps, uint32_t srcClock_Hz)
	Sets the LPUART instance baudrate. More...

Status
uint32_t	LPUART_GetStatusFlags (LPUART_Type *base)
	Gets LPUART status flags. More...

status_t	LPUART_ClearStatusFlags (LPUART_Type *base, uint32_t mask)
	Clears status flags with a provided mask. More...

Interrupts
void	LPUART_EnableInterrupts (LPUART_Type *base, uint32_t mask)
	Enables LPUART interrupts according to a provided mask. More...

void	LPUART_DisableInterrupts (LPUART_Type *base, uint32_t mask)
	Disables LPUART interrupts according to a provided mask. More...

uint32_t	LPUART_GetEnabledInterrupts (LPUART_Type *base)
	Gets enabled LPUART interrupts. More...

Bus Operations
static void	LPUART_EnableTx (LPUART_Type *base, bool enable)
	Enables or disables the LPUART transmitter. More...

static void	LPUART_EnableRx (LPUART_Type *base, bool enable)
	Enables or disables the LPUART receiver. More...

static void	LPUART_WriteByte (LPUART_Type *base, uint8_t data)
	Writes to the transmitter register. More...

static uint8_t	LPUART_ReadByte (LPUART_Type *base)
	Reads the RX register. More...

void	LPUART_WriteBlocking (LPUART_Type base, const uint8_t data, size_t length)
	Writes to transmitter register using a blocking method. More...

status_t	LPUART_ReadBlocking (LPUART_Type base, uint8_t data, size_t length)
	Reads the RX data register using a blocking method. More...

Transactional
void	LPUART_TransferCreateHandle (LPUART_Type base, lpuart_handle_t handle, lpuart_transfer_callback_t callback, void *userData)
	Initializes the LPUART handle. More...

status_t	LPUART_TransferSendNonBlocking (LPUART_Type base, lpuart_handle_t handle, lpuart_transfer_t *xfer)
	Transmits a buffer of data using the interrupt method. More...

void	LPUART_TransferStartRingBuffer (LPUART_Type base, lpuart_handle_t handle, uint8_t *ringBuffer, size_t ringBufferSize)
	Sets up the RX ring buffer. More...

void	LPUART_TransferStopRingBuffer (LPUART_Type base, lpuart_handle_t handle)
	Abort the background transfer and uninstall the ring buffer. More...

void	LPUART_TransferAbortSend (LPUART_Type base, lpuart_handle_t handle)
	Aborts the interrupt-driven data transmit. More...

status_t	LPUART_TransferGetSendCount (LPUART_Type base, lpuart_handle_t handle, uint32_t *count)
	Get the number of bytes that have been written to LPUART TX register. More...

status_t	LPUART_TransferReceiveNonBlocking (LPUART_Type base, lpuart_handle_t handle, lpuart_transfer_t xfer, size_t receivedBytes)
	Receives a buffer of data using the interrupt method. More...

void	LPUART_TransferAbortReceive (LPUART_Type base, lpuart_handle_t handle)
	Aborts the interrupt-driven data receiving. More...

status_t	LPUART_TransferGetReceiveCount (LPUART_Type base, lpuart_handle_t handle, uint32_t *count)
	Get the number of bytes that have been received. More...

void	LPUART_TransferHandleIRQ (LPUART_Type base, lpuart_handle_t handle)
	LPUART IRQ handle function. More...

void	LPUART_TransferHandleErrorIRQ (LPUART_Type base, lpuart_handle_t handle)
	LPUART Error IRQ handle function. More...

Data Structure Documentation

struct lpuart_config_t

Data Fields
uint32_t	baudRate_Bps
	LPUART baud rate.

lpuart_parity_mode_t	parityMode
	Parity mode, disabled (default), even, odd.

lpuart_data_bits_t	dataBitsCount
	Data bits count, eight (default), seven.

bool	isMsb
	Data bits order, LSB (default), MSB.

bool	enableTx
	Enable TX.

bool	enableRx
	Enable RX.

struct lpuart_transfer_t

Data Fields
uint8_t *	data
	The buffer of data to be transfer. More...

size_t	dataSize
	The byte count to be transfer. More...

Field Documentation

uint8_t* lpuart_transfer_t::data

size_t lpuart_transfer_t::dataSize

struct _lpuart_handle

Data Fields
uint8_t *volatile	txData
	Address of remaining data to send. More...

volatile size_t	txDataSize
	Size of the remaining data to send. More...

size_t	txDataSizeAll
	Size of the data to send out. More...

uint8_t *volatile	rxData
	Address of remaining data to receive. More...

volatile size_t	rxDataSize
	Size of the remaining data to receive. More...

size_t	rxDataSizeAll
	Size of the data to receive. More...

uint8_t *	rxRingBuffer
	Start address of the receiver ring buffer. More...

size_t	rxRingBufferSize
	Size of the ring buffer. More...

volatile uint16_t	rxRingBufferHead
	Index for the driver to store received data into ring buffer. More...

volatile uint16_t	rxRingBufferTail
	Index for the user to get data from the ring buffer. More...

lpuart_transfer_callback_t	callback
	Callback function. More...

void *	userData
	LPUART callback function parameter. More...

volatile uint8_t	txState
	TX transfer state. More...

volatile uint8_t	rxState
	RX transfer state. More...

Field Documentation

uint8_t* volatile lpuart_handle_t::txData

volatile size_t lpuart_handle_t::txDataSize

size_t lpuart_handle_t::txDataSizeAll

uint8_t* volatile lpuart_handle_t::rxData

volatile size_t lpuart_handle_t::rxDataSize

size_t lpuart_handle_t::rxDataSizeAll

uint8_t* lpuart_handle_t::rxRingBuffer

size_t lpuart_handle_t::rxRingBufferSize

volatile uint16_t lpuart_handle_t::rxRingBufferHead

volatile uint16_t lpuart_handle_t::rxRingBufferTail

lpuart_transfer_callback_t lpuart_handle_t::callback

void* lpuart_handle_t::userData

volatile uint8_t lpuart_handle_t::txState

volatile uint8_t lpuart_handle_t::rxState

Macro Definition Documentation

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

Typedef Documentation

typedef void(* lpuart_transfer_callback_t)(LPUART_Type *base, lpuart_handle_t *handle, status_t status, void *userData)

Enumeration Type Documentation

enum _lpuart_status

Enumerator
kStatus_LPUART_TxBusy	TX busy.
kStatus_LPUART_RxBusy	RX busy.
kStatus_LPUART_TxIdle	LPUART transmitter is idle.
kStatus_LPUART_RxIdle	LPUART receiver is idle.
kStatus_LPUART_TxWatermarkTooLarge	TX FIFO watermark too large.
kStatus_LPUART_RxWatermarkTooLarge	RX FIFO watermark too large.
kStatus_LPUART_FlagCannotClearManually	Some flag can't manually clear.
kStatus_LPUART_Error	Error happens on LPUART.
kStatus_LPUART_RxRingBufferOverrun	LPUART RX software ring buffer overrun.
kStatus_LPUART_RxHardwareOverrun	LPUART RX receiver overrun.
kStatus_LPUART_NoiseError	LPUART noise error.
kStatus_LPUART_FramingError	LPUART framing error.
kStatus_LPUART_ParityError	LPUART parity error.
kStatus_LPUART_BaudrateNotSupport	Baudrate is not support in current clock source.

enum lpuart_parity_mode_t

Enumerator
kLPUART_ParityDisabled	Parity disabled.
kLPUART_ParityEven	Parity enabled, type even, bit setting: PE\|PT = 10.
kLPUART_ParityOdd	Parity enabled, type odd, bit setting: PE\|PT = 11.

enum lpuart_data_bits_t

Enumerator
kLPUART_EightDataBits	Eight data bit.

enum lpuart_stop_bit_count_t

Enumerator
kLPUART_OneStopBit	One stop bit.
kLPUART_TwoStopBit	Two stop bits.

enum _lpuart_interrupt_enable

This structure contains the settings for all LPUART interrupt configurations.

Enumerator
kLPUART_RxActiveEdgeInterruptEnable	Receive Active Edge.
kLPUART_TxDataRegEmptyInterruptEnable	Transmit data register empty.
kLPUART_TransmissionCompleteInterruptEnable	Transmission complete.
kLPUART_RxDataRegFullInterruptEnable	Receiver data register full.
kLPUART_IdleLineInterruptEnable	Idle line.
kLPUART_RxOverrunInterruptEnable	Receiver Overrun.
kLPUART_NoiseErrorInterruptEnable	Noise error flag.
kLPUART_FramingErrorInterruptEnable	Framing error flag.
kLPUART_ParityErrorInterruptEnable	Parity error flag.

enum _lpuart_flags

This provides constants for the LPUART status flags for use in the LPUART functions.

Enumerator
kLPUART_TxDataRegEmptyFlag	Transmit data register empty flag, sets when transmit buffer is empty.
kLPUART_TransmissionCompleteFlag	Transmission complete flag, sets when transmission activity complete.
kLPUART_RxDataRegFullFlag	Receive data register full flag, sets when the receive data buffer is full.
kLPUART_IdleLineFlag	Idle line detect flag, sets when idle line detected.
kLPUART_RxOverrunFlag	Receive Overrun, sets when new data is received before data is read from receive register.
kLPUART_NoiseErrorFlag	Receive takes 3 samples of each received bit. If any of these samples differ, noise flag sets
kLPUART_FramingErrorFlag	Frame error flag, sets if logic 0 was detected where stop bit expected.
kLPUART_ParityErrorFlag	If parity enabled, sets upon parity error detection.
kLPUART_RxActiveEdgeFlag	Receive pin active edge interrupt flag, sets when active edge detected.
kLPUART_RxActiveFlag	Receiver Active Flag (RAF), sets at beginning of valid start bit.

Function Documentation

status_t LPUART_Init	(	LPUART_Type *	base,
		const lpuart_config_t *	config,
		uint32_t	srcClock_Hz
	)

This function configures the LPUART module with user-defined settings. Call the LPUART_GetDefaultConfig() function to configure the configuration structure and get the default configuration. The example below shows how to use this API to configure the LPUART.

*  lpuart_config_t lpuartConfig;
*  lpuartConfig.baudRate_Bps = 115200U;
*  lpuartConfig.parityMode = kLPUART_ParityDisabled;
*  lpuartConfig.dataBitsCount = kLPUART_EightDataBits;
*  lpuartConfig.isMsb = false;
*  lpuartConfig.stopBitCount = kLPUART_OneStopBit;
*  lpuartConfig.txFifoWatermark = 0;
*  lpuartConfig.rxFifoWatermark = 1;
*  LPUART_Init(LPUART1, &lpuartConfig, 20000000U);
* 

Parameters

base	LPUART peripheral base address.
config	Pointer to a user-defined configuration structure.
srcClock_Hz	LPUART clock source frequency in HZ.

Return values

kStatus_LPUART_BaudrateNotSupport	Baudrate is not support in current clock source.
kStatus_Success	LPUART initialize succeed

void LPUART_Deinit ( LPUART_Type * base )

This function waits for transmit to complete, disables TX and RX, and disables the LPUART clock.

Parameters

base	LPUART peripheral base address.

void LPUART_GetDefaultConfig ( lpuart_config_t * config )

This function initializes the LPUART configuration structure to a default value. The default values are: lpuartConfig->baudRate_Bps = 115200U; lpuartConfig->parityMode = kLPUART_ParityDisabled; lpuartConfig->dataBitsCount = kLPUART_EightDataBits; lpuartConfig->isMsb = false; lpuartConfig->stopBitCount = kLPUART_OneStopBit; lpuartConfig->txFifoWatermark = 0; lpuartConfig->rxFifoWatermark = 1; lpuartConfig->enableTx = false; lpuartConfig->enableRx = false;

Parameters

config Pointer to a configuration structure.

status_t LPUART_SetBaudRate	(	LPUART_Type *	base,
		uint32_t	baudRate_Bps,
		uint32_t	srcClock_Hz
	)

This function configures the LPUART module baudrate. This function is used to update the LPUART module baudrate after the LPUART module is initialized by the LPUART_Init.

* LPUART_SetBaudRate(LPUART1, 115200U, 20000000U);

*

Parameters

base	LPUART peripheral base address.
baudRate_Bps	LPUART baudrate to be set.
srcClock_Hz	LPUART clock source frequency in HZ.

Return values

kStatus_LPUART_BaudrateNotSupport	Baudrate is not supported in the current clock source.
kStatus_Success	Set baudrate succeeded.

uint32_t LPUART_GetStatusFlags ( LPUART_Type * base )

This function gets all LPUART status flags. The flags are returned as the logical OR value of the enumerators _lpuart_flags. To check for a specific status, compare the return value with enumerators in the _lpuart_flags. For example, to check whether the TX is empty:

*     if (kLPUART_TxDataRegEmptyFlag & LPUART_GetStatusFlags(LPUART1))
*     {
*         ...
*     }
* 

Parameters

base	LPUART peripheral base address.

Returns: LPUART status flags which are ORed by the enumerators in the _lpuart_flags.

status_t LPUART_ClearStatusFlags	(	LPUART_Type *	base,
		uint32_t	mask
	)

This function clears LPUART status flags with a provided mask. Automatically cleared flags can't be cleared by this function. Flags that can only cleared or set by hardware are: kLPUART_TxDataRegEmptyFlag, kLPUART_TransmissionCompleteFlag, kLPUART_RxDataRegFullFlag, kLPUART_RxActiveFlag, kLPUART_NoiseErrorInRxDataRegFlag, kLPUART_ParityErrorInRxDataRegFlag, kLPUART_TxFifoEmptyFlag,kLPUART_RxFifoEmptyFlag Note: This API should be called when the Tx/Rx is idle, otherwise it takes no effects.

Parameters

base	LPUART peripheral base address.
mask	the status flags to be cleared. The user can use the enumerators in the _lpuart_status_flag_t to do the OR operation and get the mask.

Returns: 0 succeed, others failed.

Return values

kStatus_LPUART_FlagCannotClearManually	The flag can't be cleared by this function but it is cleared automatically by hardware.
kStatus_Success	Status in the mask are cleared.

void LPUART_EnableInterrupts	(	LPUART_Type *	base,
		uint32_t	mask
	)

This function enables the LPUART interrupts according to a provided mask. The mask is a logical OR of enumeration members. See the _lpuart_interrupt_enable. This examples shows how to enable TX empty interrupt and RX full interrupt:

* LPUART_EnableInterrupts(LPUART1,kLPUART_TxDataRegEmptyInterruptEnable | kLPUART_RxDataRegFullInterruptEnable);

*

Parameters

base	LPUART peripheral base address.
mask	The interrupts to enable. Logical OR of _uart_interrupt_enable.

void LPUART_DisableInterrupts	(	LPUART_Type *	base,
		uint32_t	mask
	)

This function disables the LPUART interrupts according to a provided mask. The mask is a logical OR of enumeration members. See _lpuart_interrupt_enable. This example shows how to disable the TX empty interrupt and RX full interrupt:

* LPUART_DisableInterrupts(LPUART1,kLPUART_TxDataRegEmptyInterruptEnable | kLPUART_RxDataRegFullInterruptEnable);

*

Parameters

base	LPUART peripheral base address.
mask	The interrupts to disable. Logical OR of _lpuart_interrupt_enable.

uint32_t LPUART_GetEnabledInterrupts ( LPUART_Type * base )

This function gets the enabled LPUART interrupts. The enabled interrupts are returned as the logical OR value of the enumerators _lpuart_interrupt_enable. To check a specific interrupt enable status, compare the return value with enumerators in _lpuart_interrupt_enable. For example, to check whether the TX empty interrupt is enabled:

*     uint32_t enabledInterrupts = LPUART_GetEnabledInterrupts(LPUART1);
*
*     if (kLPUART_TxDataRegEmptyInterruptEnable & enabledInterrupts)
*     {
*         ...
*     }
* 

Parameters

base	LPUART peripheral base address.

Returns: LPUART interrupt flags which are logical OR of the enumerators in _lpuart_interrupt_enable.

static void LPUART_EnableTx	(	LPUART_Type *	base,
		bool	enable
	)

inlinestatic

This function enables or disables the LPUART transmitter.

Parameters

base	LPUART peripheral base address.
enable	True to enable, false to disable.

static void LPUART_EnableRx	(	LPUART_Type *	base,
		bool	enable
	)

inlinestatic

This function enables or disables the LPUART receiver.

Parameters

base	LPUART peripheral base address.
enable	True to enable, false to disable.

static void LPUART_WriteByte	(	LPUART_Type *	base,
		uint8_t	data
	)

inlinestatic

This function writes data to the transmitter register directly. The upper layer must ensure that the TX register is empty or that the TX FIFO has room before calling this function.

Parameters

base	LPUART peripheral base address.
data	Data write to the TX register.

static uint8_t LPUART_ReadByte ( LPUART_Type * base )

inlinestatic

This function reads data from the receiver register directly. The upper layer must ensure that the RX register is full or that the RX FIFO has data before calling this function.

Parameters

base	LPUART peripheral base address.

Returns: Data read from data register.

void LPUART_WriteBlocking	(	LPUART_Type *	base,
		const uint8_t *	data,
		size_t	length
	)

This function polls the transmitter register, waits for the register to be empty or for TX FIFO to have room and then writes data to the transmitter buffer.

Note: This function does not check whether all data has been sent out to the bus. Before disabling the transmitter, check the kLPUART_TransmissionCompleteFlag to ensure that the transmit is finished.

Parameters

base	LPUART peripheral base address.
data	Start address of the data to write.
length	Size of the data to write.

status_t LPUART_ReadBlocking	(	LPUART_Type *	base,
		uint8_t *	data,
		size_t	length
	)

This function polls the RX register, waits for the RX register full or RX FIFO has data then reads data from the TX register.

Parameters

base	LPUART peripheral base address.
data	Start address of the buffer to store the received data.
length	Size of the buffer.

Return values

kStatus_LPUART_RxHardwareOverrun	Receiver overrun happened while receiving data.
kStatus_LPUART_NoiseError	Noise error happened while receiving data.
kStatus_LPUART_FramingError	Framing error happened while receiving data.
kStatus_LPUART_ParityError	Parity error happened while receiving data.
kStatus_Success	Successfully received all data.

void LPUART_TransferCreateHandle	(	LPUART_Type *	base,
		lpuart_handle_t *	handle,
		lpuart_transfer_callback_t	callback,
		void *	userData
	)

This function initializes the LPUART handle, which can be used for other LPUART transactional APIs. Usually, for a specified LPUART instance, call this API once to get the initialized handle.

The LPUART driver supports the "background" receiving, which means that user can set up an RX ring buffer optionally. Data received is stored into the ring buffer even when the user doesn't call the LPUART_TransferReceiveNonBlocking() API. If there is already data received in the ring buffer, the user can get the received data from the ring buffer directly. The ring buffer is disabled if passing NULL as ringBuffer.

Parameters

base	LPUART peripheral base address.
handle	LPUART handle pointer.
callback	Callback function.
userData	User data.

status_t LPUART_TransferSendNonBlocking	(	LPUART_Type *	base,
		lpuart_handle_t *	handle,
		lpuart_transfer_t *	xfer
	)

This function send data using an interrupt method. This is a non-blocking function, which returns directly without waiting for all data written to the transmitter register. When all data is written to the TX register in the ISR, the LPUART driver calls the callback function and passes the kStatus_LPUART_TxIdle as status parameter.

Note: The kStatus_LPUART_TxIdle is passed to the upper layer when all data are written to the TX register. However, there is no check to ensure that all the data sent out. Before disabling the TX, check the kLPUART_TransmissionCompleteFlag to ensure that the transmit is finished.

Parameters

base	LPUART peripheral base address.
handle	LPUART handle pointer.
xfer	LPUART transfer structure, see lpuart_transfer_t.

Return values

kStatus_Success	Successfully start the data transmission.
kStatus_LPUART_TxBusy	Previous transmission still not finished, data not all written to the TX register.
kStatus_InvalidArgument	Invalid argument.

void LPUART_TransferStartRingBuffer	(	LPUART_Type *	base,
		lpuart_handle_t *	handle,
		uint8_t *	ringBuffer,
		size_t	ringBufferSize
	)

This function sets up the RX ring buffer to a specific UART handle.

When the RX ring buffer is used, data received is stored into the ring buffer even when the user doesn't call the UART_TransferReceiveNonBlocking() API. If there is already data received in the ring buffer, the user can get the received data from the ring buffer directly.

Note: When using RX ring buffer, one byte is reserved for internal use. In other words, if ringBufferSize is 32, then only 31 bytes are used for saving data.

Parameters

base	LPUART peripheral base address.
handle	LPUART handle pointer.
ringBuffer	Start address of ring buffer for background receiving. Pass NULL to disable the ring buffer.
ringBufferSize	size of the ring buffer.

void LPUART_TransferStopRingBuffer	(	LPUART_Type *	base,
		lpuart_handle_t *	handle
	)

This function aborts the background transfer and uninstalls the ring buffer.

Parameters

base	LPUART peripheral base address.
handle	LPUART handle pointer.

void LPUART_TransferAbortSend	(	LPUART_Type *	base,
		lpuart_handle_t *	handle
	)

This function aborts the interrupt driven data sending. The user can get the remainBtyes to find out how many bytes are still not sent out.

Parameters

base	LPUART peripheral base address.
handle	LPUART handle pointer.

status_t LPUART_TransferGetSendCount	(	LPUART_Type *	base,
		lpuart_handle_t *	handle,
		uint32_t *	count
	)

This function gets the number of bytes that have been written to LPUART TX register by interrupt method.

Parameters

base	LPUART peripheral base address.
handle	LPUART handle pointer.
count	Send bytes count.

Return values

kStatus_NoTransferInProgress	No send in progress.
kStatus_InvalidArgument	Parameter is invalid.
kStatus_Success	Get successfully through the parameter `count`;

status_t LPUART_TransferReceiveNonBlocking	(	LPUART_Type *	base,
		lpuart_handle_t *	handle,
		lpuart_transfer_t *	xfer,
		size_t *	receivedBytes
	)

This function receives data using an interrupt method. This is a non-blocking function which returns without waiting to ensure that all data are received. If the RX ring buffer is used and not empty, the data in the ring buffer is copied and the parameter receivedBytes shows how many bytes are copied from the ring buffer. After copying, if the data in the ring buffer is not enough for read, the receive request is saved by the LPUART driver. When the new data arrives, the receive request is serviced first. When all data is received, the LPUART driver notifies the upper layer through a callback function and passes a status parameter kStatus_UART_RxIdle. For example, the upper layer needs 10 bytes but there are only 5 bytes in ring buffer. The 5 bytes are copied to xfer->data, which returns with the parameter receivedBytes set to 5. For the remaining 5 bytes, the newly arrived data is saved from xfer->data[5]. When 5 bytes are received, the LPUART driver notifies the upper layer. If the RX ring buffer is not enabled, this function enables the RX and RX interrupt to receive data to xfer->data. When all data is received, the upper layer is notified.

Parameters

base	LPUART peripheral base address.
handle	LPUART handle pointer.
xfer	LPUART transfer structure, see #uart_transfer_t.
receivedBytes	Bytes received from the ring buffer directly.

Return values

kStatus_Success	Successfully queue the transfer into the transmit queue.
kStatus_LPUART_RxBusy	Previous receive request is not finished.
kStatus_InvalidArgument	Invalid argument.

void LPUART_TransferAbortReceive	(	LPUART_Type *	base,
		lpuart_handle_t *	handle
	)

This function aborts the interrupt-driven data receiving. The user can get the remainBytes to find out how many bytes not received yet.

Parameters

base	LPUART peripheral base address.
handle	LPUART handle pointer.

status_t LPUART_TransferGetReceiveCount	(	LPUART_Type *	base,
		lpuart_handle_t *	handle,
		uint32_t *	count
	)

This function gets the number of bytes that have been received.

Parameters

base	LPUART peripheral base address.
handle	LPUART handle pointer.
count	Receive bytes count.

Return values

kStatus_NoTransferInProgress	No receive in progress.
kStatus_InvalidArgument	Parameter is invalid.
kStatus_Success	Get successfully through the parameter `count`;

void LPUART_TransferHandleIRQ	(	LPUART_Type *	base,
		lpuart_handle_t *	handle
	)

This function handles the LPUART transmit and receive IRQ request.

Parameters

base	LPUART peripheral base address.
handle	LPUART handle pointer.

void LPUART_TransferHandleErrorIRQ	(	LPUART_Type *	base,
		lpuart_handle_t *	handle
	)

This function handles the LPUART error IRQ request.

Parameters

base	LPUART peripheral base address.
handle	LPUART handle pointer.

Overview

Typical use case

LPUART Operation

Data Structures

Typedefs

Enumerations

Driver version

Initialization and deinitialization

Status

Interrupts

Bus Operations

Transactional

Data Structure Documentation

Data Fields

Data Fields

Field Documentation

Data Fields

Field Documentation

Macro Definition Documentation

Typedef Documentation

Enumeration Type Documentation

Function Documentation