Overview

The MCUXpresso SDK provides a peripheral driver for the Universal Asynchronous Receiver/Transmitter (UART) function using the Flexible I/O.

FlexIO UART driver includes functional APIs and transactional APIs. Functional APIs target low-level APIs. Functional APIs can be used for the FlexIO UART initialization/configuration/operation for optimization/customization purpose. Using the functional APIs requires the knowledge of the FlexIO UART peripheral and how to organize functional APIs to meet the application requirements. All functional API use the FLEXIO_UART_Type * as the first parameter. FlexIO UART functional operation groups provide the functional APIs set.

Transactional APIs target high-level APIs. Transactional APIs can be used to enable the peripheral and also in the application if the code size and performance of transactional APIs satisfy requirements. If the code size and performance are critical requirements, see the transactional API implementation and write custom code. All transactional APIs use the flexio_uart_handle_t as the second parameter. Initialize the handle by calling the FLEXIO_UART_TransferCreateHandle() API.

Transactional APIs support asynchronous transfer. This means that the functions FLEXIO_UART_SendNonBlocking() and FLEXIO_UART_ReceiveNonBlocking() set up an interrupt for data transfer. When the transfer is complete, the upper layer is notified through a callback function with the kStatus_FLEXIO_UART_TxIdle and kStatus_FLEXIO_UART_RxIdle status.

Transactional receive APIs support the ring buffer. Prepare the memory for the ring buffer and pass in the start address and size through calling the FLEXIO_UART_InstallRingBuffer(). When the ring buffer is enabled, the received data is saved to the ring buffer in the background. The function FLEXIO_UART_ReceiveNonBlocking() first gets data the from the ring buffer. If ring buffer does not have enough data, the function returns the data to the ring buffer and saves the received data to user memory. When all data is received, the upper layer is informed through a callback with the statuskStatus_FLEXIO_UART_RxIdle status.

If the receive ring buffer is full, the upper layer is informed through a callback with status kStatus_FLEXIO_UART_RxRingBufferOverrun. In the callback function, the upper layer reads data from the ring buffer. If not, the oldest data is overwritten by the new data.

The ring buffer size is specified when calling the FLEXIO_UART_InstallRingBuffer. Note that one byte is reserved for the ring buffer maintenance. Create a handle as follows.

FLEXIO_UART_InstallRingBuffer(&uartDev, &handle, &ringBuffer, 32);

In this example, the buffer size is 32. However, only 31 bytes are used for saving data.

Typical use case

FlexIO UART send/receive using a polling method

uint8_t ch;
FLEXIO_UART_Type uartDev;
status_t result = kStatus_Success;
flexio_uart_user_config user_config;
FLEXIO_UART_GetDefaultConfig(&user_config);
user_config.baudRate_Bps = 115200U;
user_config.enableUart = true;
uartDev.flexioBase = BOARD_FLEXIO_BASE;
uartDev.TxPinIndex = FLEXIO_UART_TX_PIN;
uartDev.RxPinIndex = FLEXIO_UART_RX_PIN;
uartDev.shifterIndex[0] = 0U;
uartDev.shifterIndex[1] = 1U;
uartDev.timerIndex[0] = 0U;
uartDev.timerIndex[1] = 1U;
result = FLEXIO_UART_Init(&uartDev, &user_config, 48000000U);
//Check if configuration is correct.
if(result != kStatus_Success)
{
    return;
}
FLEXIO_UART_WriteBlocking(&uartDev, txbuff, sizeof(txbuff));
while(1)
{
    FLEXIO_UART_ReadBlocking(&uartDev, &ch, 1);
    FLEXIO_UART_WriteBlocking(&uartDev, &ch, 1);
}

FlexIO UART send/receive using an interrupt method

FLEXIO_UART_Type uartDev;
flexio_uart_handle_t g_uartHandle;
flexio_uart_config_t user_config;
flexio_uart_transfer_t sendXfer;
flexio_uart_transfer_t receiveXfer;
volatile bool txFinished;
volatile bool rxFinished;
uint8_t sendData[] = ['H', 'e', 'l', 'l', 'o'];
uint8_t receiveData[32];
void FLEXIO_UART_UserCallback(FLEXIO_UART_Type *base, flexio_uart_handle_t *handle, status_t status, void *userData)
{
    userData = userData;
    if (kStatus_FLEXIO_UART_TxIdle == status)
    {
        txFinished = true;
    }
    if (kStatus_FLEXIO_UART_RxIdle == status)
    {
        rxFinished = true;
    }
}
void main(void)
{
    //...
    FLEXIO_UART_GetDefaultConfig(&user_config);
    user_config.baudRate_Bps = 115200U;
    user_config.enableUart = true;
    uartDev.flexioBase = BOARD_FLEXIO_BASE;
    uartDev.TxPinIndex = FLEXIO_UART_TX_PIN;
    uartDev.RxPinIndex = FLEXIO_UART_RX_PIN;
    uartDev.shifterIndex[0] = 0U;
    uartDev.shifterIndex[1] = 1U;
    uartDev.timerIndex[0] = 0U;
    uartDev.timerIndex[1] = 1U;
    result = FLEXIO_UART_Init(&uartDev, &user_config, 120000000U);
    //Check if configuration is correct.
    if(result != kStatus_Success)
    {
        return;
    }
    FLEXIO_UART_TransferCreateHandle(&uartDev, &g_uartHandle, FLEXIO_UART_UserCallback, NULL);
    // Prepares to send.
    sendXfer.data = sendData;
    sendXfer.dataSize = sizeof(sendData)/sizeof(sendData[0]);
    txFinished = false;
    // Sends out.
    FLEXIO_UART_SendNonBlocking(&uartDev, &g_uartHandle, &sendXfer);
    // Send finished.
    while (!txFinished)
    {
    }
    // Prepares to receive.
    receiveXfer.data = receiveData;
    receiveXfer.dataSize = sizeof(receiveData)/sizeof(receiveData[0]);
    rxFinished = false;
    // Receives.
    FLEXIO_UART_ReceiveNonBlocking(&uartDev, &g_uartHandle, &receiveXfer, NULL);
    // Receive finished.
    while (!rxFinished)
    {
    }
    // ...
}

FlexIO UART receive using the ringbuffer feature

#define RING_BUFFER_SIZE 64
#define RX_DATA_SIZE     32
FLEXIO_UART_Type uartDev;
flexio_uart_handle_t g_uartHandle;
flexio_uart_config_t user_config;
flexio_uart_transfer_t sendXfer;
flexio_uart_transfer_t receiveXfer;
volatile bool txFinished;
volatile bool rxFinished;
uint8_t receiveData[RX_DATA_SIZE];
uint8_t ringBuffer[RING_BUFFER_SIZE];
void FLEXIO_UART_UserCallback(FLEXIO_UART_Type *base, flexio_uart_handle_t *handle, status_t status, void *userData)
{
    userData = userData;
    if (kStatus_FLEXIO_UART_RxIdle == status)
    {
        rxFinished = true;
    }
}
void main(void)
{
    size_t bytesRead;
    //...
    FLEXIO_UART_GetDefaultConfig(&user_config);
    user_config.baudRate_Bps = 115200U;
    user_config.enableUart = true;
    uartDev.flexioBase = BOARD_FLEXIO_BASE;
    uartDev.TxPinIndex = FLEXIO_UART_TX_PIN;
    uartDev.RxPinIndex = FLEXIO_UART_RX_PIN;
    uartDev.shifterIndex[0] = 0U;
    uartDev.shifterIndex[1] = 1U;
    uartDev.timerIndex[0] = 0U;
    uartDev.timerIndex[1] = 1U;
    result = FLEXIO_UART_Init(&uartDev, &user_config, 48000000U);
    //Check if configuration is correct.
    if(result != kStatus_Success)
    {
        return;
    }
    FLEXIO_UART_TransferCreateHandle(&uartDev, &g_uartHandle, FLEXIO_UART_UserCallback, NULL);
    FLEXIO_UART_InstallRingBuffer(&uartDev, &g_uartHandle, ringBuffer, RING_BUFFER_SIZE);
    // Receive is working in the background to the ring buffer.
    // Prepares to receive.
    receiveXfer.data = receiveData;
    receiveXfer.dataSize = RX_DATA_SIZE;
    rxFinished = false;
    // Receives.
    FLEXIO_UART_ReceiveNonBlocking(&uartDev, &g_uartHandle, &receiveXfer, &bytesRead);
    if (bytesRead = RX_DATA_SIZE) /* Have read enough data. */
    {
        ;
    }
    else
    {
        if (bytesRead) /* Received some data, process first. */
        {
            ;
        }
        // Receive finished.
        while (!rxFinished)
        {
        }
    }
    // ...
}

FlexIO UART send/receive using a DMA method

    FLEXIO_UART_Type uartDev;
    flexio_uart_handle_t g_uartHandle;
    dma_handle_t g_uartTxDmaHandle;
    dma_handle_t g_uartRxDmaHandle;
    flexio_uart_config_t user_config;
    flexio_uart_transfer_t sendXfer;
    flexio_uart_transfer_t receiveXfer;
    volatile bool txFinished;
    volatile bool rxFinished;
    uint8_t sendData[] = ['H', 'e', 'l', 'l', 'o'];
    uint8_t receiveData[32];
    void FLEXIO_UART_UserCallback(FLEXIO_UART_Type *base, flexio_uart_handle_t *handle, status_t status, void *userData)
    {
        userData = userData;
        if (kStatus_FLEXIO_UART_TxIdle == status)
        {
            txFinished = true;
        }
        if (kStatus_FLEXIO_UART_RxIdle == status)
        {
            rxFinished = true;
        }
    }
    void main(void)
    {
        //...
        FLEXIO_UART_GetDefaultConfig(&user_config);
        user_config.baudRate_Bps = 115200U;
        user_config.enableUart = true;
        uartDev.flexioBase = BOARD_FLEXIO_BASE;
        uartDev.TxPinIndex = FLEXIO_UART_TX_PIN;
        uartDev.RxPinIndex = FLEXIO_UART_RX_PIN;
        uartDev.shifterIndex[0] = 0U;
        uartDev.shifterIndex[1] = 1U;
        uartDev.timerIndex[0] = 0U;
        uartDev.timerIndex[1] = 1U;
        result = FLEXIO_UART_Init(&uartDev, &user_config, 48000000U);
        //Check if configuration is correct.
        if(result != kStatus_Success)
        {
            return;
        }
        /* Init DMAMUX. */
        DMAMUX_Init(EXAMPLE_FLEXIO_UART_DMAMUX_BASEADDR)
        /* Init the DMA/EDMA module */
#if defined(FSL_FEATURE_SOC_DMA_COUNT) && FSL_FEATURE_SOC_DMA_COUNT > 0U
        DMA_Init(EXAMPLE_FLEXIO_UART_DMA_BASEADDR);
        DMA_CreateHandle(&g_uartTxDmaHandle, EXAMPLE_FLEXIO_UART_DMA_BASEADDR, FLEXIO_UART_TX_DMA_CHANNEL);
        DMA_CreateHandle(&g_uartRxDmaHandle, EXAMPLE_FLEXIO_UART_DMA_BASEADDR, FLEXIO_UART_RX_DMA_CHANNEL);
#endif /* FSL_FEATURE_SOC_DMA_COUNT */
#if defined(FSL_FEATURE_SOC_EDMA_COUNT) && FSL_FEATURE_SOC_EDMA_COUNT > 0U
        edma_config_t edmaConfig;
        EDMA_GetDefaultConfig(&edmaConfig);
        EDMA_Init(EXAMPLE_FLEXIO_UART_DMA_BASEADDR, &edmaConfig);
        EDMA_CreateHandle(&g_uartTxDmaHandle, EXAMPLE_FLEXIO_UART_DMA_BASEADDR, FLEXIO_UART_TX_DMA_CHANNEL);
        EDMA_CreateHandle(&g_uartRxDmaHandle, EXAMPLE_FLEXIO_UART_DMA_BASEADDR, FLEXIO_UART_RX_DMA_CHANNEL);
#endif /* FSL_FEATURE_SOC_EDMA_COUNT */
        dma_request_source_tx = (dma_request_source_t)(FLEXIO_DMA_REQUEST_BASE + uartDev.shifterIndex[0]);
        dma_request_source_rx = (dma_request_source_t)(FLEXIO_DMA_REQUEST_BASE + uartDev.shifterIndex[1]);
        /* Requests  DMA channels for transmit and receive. */
        DMAMUX_SetSource(EXAMPLE_FLEXIO_UART_DMAMUX_BASEADDR, FLEXIO_UART_TX_DMA_CHANNEL, (dma_request_source_t)dma_request_source_tx);
        DMAMUX_SetSource(EXAMPLE_FLEXIO_UART_DMAMUX_BASEADDR, FLEXIO_UART_RX_DMA_CHANNEL, (dma_request_source_t)dma_request_source_rx);
        DMAMUX_EnableChannel(EXAMPLE_FLEXIO_UART_DMAMUX_BASEADDR, FLEXIO_UART_TX_DMA_CHANNEL);
        DMAMUX_EnableChannel(EXAMPLE_FLEXIO_UART_DMAMUX_BASEADDR, FLEXIO_UART_RX_DMA_CHANNEL);
        FLEXIO_UART_TransferCreateHandleDMA(&uartDev, &g_uartHandle, FLEXIO_UART_UserCallback, NULL, &g_uartTxDmaHandle, &g_uartRxDmaHandle);
        // Prepares to send.
        sendXfer.data = sendData
        sendXfer.dataSize = sizeof(sendData)/sizeof(sendData[0]);
        txFinished = false;
        // Sends out.
        FLEXIO_UART_SendDMA(&uartDev, &g_uartHandle, &sendXfer);
        // Send finished.
        while (!txFinished)
        {
        }
        // Prepares to receive.
        receiveXfer.data = receiveData;
        receiveXfer.dataSize = sizeof(receiveData)/sizeof(receiveData[0]);
        rxFinished = false;
        // Receives.
        FLEXIO_UART_ReceiveDMA(&uartDev, &g_uartHandle, &receiveXfer, NULL);
        // Receive finished.
        while (!rxFinished)
        {
        }
        // ...
    }

Modules
	FlexIO DMA UART Driver

	FlexIO eDMA UART Driver

Data Structures
struct	FLEXIO_UART_Type
	Define FlexIO UART access structure typedef. More...

struct	flexio_uart_config_t
	Define FlexIO UART user configuration structure. More...

struct	flexio_uart_transfer_t
	Define FlexIO UART transfer structure. More...

struct	flexio_uart_handle_t
	Define FLEXIO UART handle structure. More...

Typedefs
typedef void(*	flexio_uart_transfer_callback_t )(FLEXIO_UART_Type base, flexio_uart_handle_t handle, status_t status, void *userData)
	FlexIO UART transfer callback function. More...

Enumerations
enum	_flexio_uart_status { kStatus_FLEXIO_UART_TxBusy = MAKE_STATUS(kStatusGroup_FLEXIO_UART, 0), kStatus_FLEXIO_UART_RxBusy = MAKE_STATUS(kStatusGroup_FLEXIO_UART, 1), kStatus_FLEXIO_UART_TxIdle = MAKE_STATUS(kStatusGroup_FLEXIO_UART, 2), kStatus_FLEXIO_UART_RxIdle = MAKE_STATUS(kStatusGroup_FLEXIO_UART, 3), kStatus_FLEXIO_UART_ERROR = MAKE_STATUS(kStatusGroup_FLEXIO_UART, 4), kStatus_FLEXIO_UART_RxRingBufferOverrun, kStatus_FLEXIO_UART_RxHardwareOverrun = MAKE_STATUS(kStatusGroup_FLEXIO_UART, 6) }
	Error codes for the UART driver. More...

enum	flexio_uart_bit_count_per_char_t { kFLEXIO_UART_7BitsPerChar = 7U, kFLEXIO_UART_8BitsPerChar = 8U, kFLEXIO_UART_9BitsPerChar = 9U }
	FlexIO UART bit count per char. More...

enum	_flexio_uart_interrupt_enable { kFLEXIO_UART_TxDataRegEmptyInterruptEnable = 0x1U, kFLEXIO_UART_RxDataRegFullInterruptEnable = 0x2U }
	Define FlexIO UART interrupt mask. More...

enum	_flexio_uart_status_flags { kFLEXIO_UART_TxDataRegEmptyFlag = 0x1U, kFLEXIO_UART_RxDataRegFullFlag = 0x2U, kFLEXIO_UART_RxOverRunFlag = 0x4U }
	Define FlexIO UART status mask. More...

Driver version
#define	FSL_FLEXIO_UART_DRIVER_VERSION (MAKE_VERSION(2, 1, 2))
	FlexIO UART driver version 2.1.2. More...

Initialization and deinitialization
status_t	FLEXIO_UART_Init (FLEXIO_UART_Type base, const flexio_uart_config_t userConfig, uint32_t srcClock_Hz)
	Ungates the FlexIO clock, resets the FlexIO module, configures FlexIO UART hardware, and configures the FlexIO UART with FlexIO UART configuration. More...

void	FLEXIO_UART_Deinit (FLEXIO_UART_Type *base)
	Resets the FlexIO UART shifter and timer config. More...

void	FLEXIO_UART_GetDefaultConfig (flexio_uart_config_t *userConfig)
	Gets the default configuration to configure the FlexIO UART. More...

Status
uint32_t	FLEXIO_UART_GetStatusFlags (FLEXIO_UART_Type *base)
	Gets the FlexIO UART status flags. More...

void	FLEXIO_UART_ClearStatusFlags (FLEXIO_UART_Type *base, uint32_t mask)
	Gets the FlexIO UART status flags. More...

Interrupts
void	FLEXIO_UART_EnableInterrupts (FLEXIO_UART_Type *base, uint32_t mask)
	Enables the FlexIO UART interrupt. More...

void	FLEXIO_UART_DisableInterrupts (FLEXIO_UART_Type *base, uint32_t mask)
	Disables the FlexIO UART interrupt. More...

DMA Control
static uint32_t	FLEXIO_UART_GetTxDataRegisterAddress (FLEXIO_UART_Type *base)
	Gets the FlexIO UARt transmit data register address. More...

static uint32_t	FLEXIO_UART_GetRxDataRegisterAddress (FLEXIO_UART_Type *base)
	Gets the FlexIO UART receive data register address. More...

static void	FLEXIO_UART_EnableTxDMA (FLEXIO_UART_Type *base, bool enable)
	Enables/disables the FlexIO UART transmit DMA. More...

static void	FLEXIO_UART_EnableRxDMA (FLEXIO_UART_Type *base, bool enable)
	Enables/disables the FlexIO UART receive DMA. More...

Bus Operations
static void	FLEXIO_UART_Enable (FLEXIO_UART_Type *base, bool enable)
	Enables/disables the FlexIO UART module operation. More...

static void	FLEXIO_UART_WriteByte (FLEXIO_UART_Type base, const uint8_t buffer)
	Writes one byte of data. More...

static void	FLEXIO_UART_ReadByte (FLEXIO_UART_Type base, uint8_t buffer)
	Reads one byte of data. More...

void	FLEXIO_UART_WriteBlocking (FLEXIO_UART_Type base, const uint8_t txData, size_t txSize)
	Sends a buffer of data bytes. More...

void	FLEXIO_UART_ReadBlocking (FLEXIO_UART_Type base, uint8_t rxData, size_t rxSize)
	Receives a buffer of bytes. More...

Transactional
status_t	FLEXIO_UART_TransferCreateHandle (FLEXIO_UART_Type base, flexio_uart_handle_t handle, flexio_uart_transfer_callback_t callback, void *userData)
	Initializes the UART handle. More...

void	FLEXIO_UART_TransferStartRingBuffer (FLEXIO_UART_Type base, flexio_uart_handle_t handle, uint8_t *ringBuffer, size_t ringBufferSize)
	Sets up the RX ring buffer. More...

void	FLEXIO_UART_TransferStopRingBuffer (FLEXIO_UART_Type base, flexio_uart_handle_t handle)
	Aborts the background transfer and uninstalls the ring buffer. More...

status_t	FLEXIO_UART_TransferSendNonBlocking (FLEXIO_UART_Type base, flexio_uart_handle_t handle, flexio_uart_transfer_t *xfer)
	Transmits a buffer of data using the interrupt method. More...

void	FLEXIO_UART_TransferAbortSend (FLEXIO_UART_Type base, flexio_uart_handle_t handle)
	Aborts the interrupt-driven data transmit. More...

status_t	FLEXIO_UART_TransferGetSendCount (FLEXIO_UART_Type base, flexio_uart_handle_t handle, size_t *count)
	Gets the number of bytes sent. More...

status_t	FLEXIO_UART_TransferReceiveNonBlocking (FLEXIO_UART_Type base, flexio_uart_handle_t handle, flexio_uart_transfer_t xfer, size_t receivedBytes)
	Receives a buffer of data using the interrupt method. More...

void	FLEXIO_UART_TransferAbortReceive (FLEXIO_UART_Type base, flexio_uart_handle_t handle)
	Aborts the receive data which was using IRQ. More...

status_t	FLEXIO_UART_TransferGetReceiveCount (FLEXIO_UART_Type base, flexio_uart_handle_t handle, size_t *count)
	Gets the number of bytes received. More...

void	FLEXIO_UART_TransferHandleIRQ (void uartType, void uartHandle)
	FlexIO UART IRQ handler function. More...

Data Structure Documentation

struct FLEXIO_UART_Type

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

uint8_t	TxPinIndex
	Pin select for UART_Tx. More...

uint8_t	RxPinIndex
	Pin select for UART_Rx. More...

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

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

Field Documentation

FLEXIO_Type* FLEXIO_UART_Type::flexioBase

uint8_t FLEXIO_UART_Type::TxPinIndex

uint8_t FLEXIO_UART_Type::RxPinIndex

uint8_t FLEXIO_UART_Type::shifterIndex[2]

uint8_t FLEXIO_UART_Type::timerIndex[2]

struct flexio_uart_config_t

Data Fields
bool	enableUart
	Enable/disable FlexIO UART TX & RX. More...

bool	enableInDoze
	Enable/disable FlexIO operation in doze mode.

bool	enableInDebug
	Enable/disable FlexIO operation in debug mode.

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...

flexio_uart_bit_count_per_char_t	bitCountPerChar
	number of bits, 7/8/9 -bit

Field Documentation

bool flexio_uart_config_t::enableUart

bool flexio_uart_config_t::enableFastAccess

uint32_t flexio_uart_config_t::baudRate_Bps

struct flexio_uart_transfer_t

Data Fields
uint8_t *	data
	Transfer buffer.

size_t	dataSize
	Transfer size.

struct _flexio_uart_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...

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	txDataSizeAll
	Total bytes to be sent. More...

size_t	rxDataSizeAll
	Total bytes to be received. 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...

flexio_uart_transfer_callback_t	callback
	Callback function. More...

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

volatile uint8_t	txState
	TX transfer state. More...

volatile uint8_t	rxState
	RX transfer state.

Field Documentation

uint8_t* volatile flexio_uart_handle_t::txData

volatile size_t flexio_uart_handle_t::txDataSize

uint8_t* volatile flexio_uart_handle_t::rxData

volatile size_t flexio_uart_handle_t::rxDataSize

size_t flexio_uart_handle_t::txDataSizeAll

size_t flexio_uart_handle_t::rxDataSizeAll

uint8_t* flexio_uart_handle_t::rxRingBuffer

size_t flexio_uart_handle_t::rxRingBufferSize

volatile uint16_t flexio_uart_handle_t::rxRingBufferHead

volatile uint16_t flexio_uart_handle_t::rxRingBufferTail

flexio_uart_transfer_callback_t flexio_uart_handle_t::callback

void* flexio_uart_handle_t::userData

volatile uint8_t flexio_uart_handle_t::txState

Macro Definition Documentation

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

Typedef Documentation

typedef void(* flexio_uart_transfer_callback_t)(FLEXIO_UART_Type *base, flexio_uart_handle_t *handle, status_t status, void *userData)

Enumeration Type Documentation

enum _flexio_uart_status

Enumerator
kStatus_FLEXIO_UART_TxBusy	Transmitter is busy.
kStatus_FLEXIO_UART_RxBusy	Receiver is busy.
kStatus_FLEXIO_UART_TxIdle	UART transmitter is idle.
kStatus_FLEXIO_UART_RxIdle	UART receiver is idle.
kStatus_FLEXIO_UART_ERROR	ERROR happens on UART.
kStatus_FLEXIO_UART_RxRingBufferOverrun	UART RX software ring buffer overrun.
kStatus_FLEXIO_UART_RxHardwareOverrun	UART RX receiver overrun.

enum flexio_uart_bit_count_per_char_t

Enumerator
kFLEXIO_UART_7BitsPerChar	7-bit data characters
kFLEXIO_UART_8BitsPerChar	8-bit data characters
kFLEXIO_UART_9BitsPerChar	9-bit data characters

enum _flexio_uart_interrupt_enable

Enumerator
kFLEXIO_UART_TxDataRegEmptyInterruptEnable	Transmit buffer empty interrupt enable.
kFLEXIO_UART_RxDataRegFullInterruptEnable	Receive buffer full interrupt enable.

enum _flexio_uart_status_flags

Enumerator
kFLEXIO_UART_TxDataRegEmptyFlag	Transmit buffer empty flag.
kFLEXIO_UART_RxDataRegFullFlag	Receive buffer full flag.
kFLEXIO_UART_RxOverRunFlag	Receive buffer over run flag.

Function Documentation

status_t FLEXIO_UART_Init	(	FLEXIO_UART_Type *	base,
		const flexio_uart_config_t *	userConfig,
		uint32_t	srcClock_Hz
	)

The configuration structure can be filled by the user or be set with default values by FLEXIO_UART_GetDefaultConfig().

Example

FLEXIO_UART_Type base = {
.flexioBase = FLEXIO,
.TxPinIndex = 0,
.RxPinIndex = 1,
.shifterIndex = {0,1},
.timerIndex = {0,1}
};
flexio_uart_config_t config = {
.enableInDoze = false,
.enableInDebug = true,
.enableFastAccess = false,
.baudRate_Bps = 115200U,
.bitCountPerChar = 8
};
FLEXIO_UART_Init(base, &config, srcClock_Hz);

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
userConfig	Pointer to the flexio_uart_config_t structure.
srcClock_Hz	FlexIO source clock in Hz.

Return values

kStatus_Success	Configuration success
kStatus_InvalidArgument	Buadrate configuration out of range

void FLEXIO_UART_Deinit ( FLEXIO_UART_Type * base )

Note: After calling this API, call the FLEXO_UART_Init to use the FlexIO UART module.

Parameters

base	Pointer to FLEXIO_UART_Type structure

void FLEXIO_UART_GetDefaultConfig ( flexio_uart_config_t * userConfig )

The configuration can be used directly for calling the FLEXIO_UART_Init(). Example:

flexio_uart_config_t config;

FLEXIO_UART_GetDefaultConfig(&userConfig);

Parameters

userConfig Pointer to the flexio_uart_config_t structure.

uint32_t FLEXIO_UART_GetStatusFlags ( FLEXIO_UART_Type * base )

Parameters

base	Pointer to the FLEXIO_UART_Type structure.

Returns: FlexIO UART status flags.

void FLEXIO_UART_ClearStatusFlags	(	FLEXIO_UART_Type *	base,
		uint32_t	mask
	)

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
mask	Status flag. The parameter can be any combination of the following values: kFLEXIO_UART_TxDataRegEmptyFlag kFLEXIO_UART_RxEmptyFlag kFLEXIO_UART_RxOverRunFlag

void FLEXIO_UART_EnableInterrupts	(	FLEXIO_UART_Type *	base,
		uint32_t	mask
	)

This function enables the FlexIO UART interrupt.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
mask	Interrupt source.

void FLEXIO_UART_DisableInterrupts	(	FLEXIO_UART_Type *	base,
		uint32_t	mask
	)

This function disables the FlexIO UART interrupt.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
mask	Interrupt source.

static uint32_t FLEXIO_UART_GetTxDataRegisterAddress ( FLEXIO_UART_Type * base )

inlinestatic

This function returns the UART data register address, which is mainly used by DMA/eDMA.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.

Returns: FlexIO UART transmit data register address.

static uint32_t FLEXIO_UART_GetRxDataRegisterAddress ( FLEXIO_UART_Type * base )

inlinestatic

This function returns the UART data register address, which is mainly used by DMA/eDMA.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.

Returns: FlexIO UART receive data register address.

static void FLEXIO_UART_EnableTxDMA	(	FLEXIO_UART_Type *	base,
		bool	enable
	)

inlinestatic

This function enables/disables the FlexIO UART Tx DMA, which means asserting the kFLEXIO_UART_TxDataRegEmptyFlag does/doesn't trigger the DMA request.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
enable	True to enable, false to disable.

static void FLEXIO_UART_EnableRxDMA	(	FLEXIO_UART_Type *	base,
		bool	enable
	)

inlinestatic

This function enables/disables the FlexIO UART Rx DMA, which means asserting kFLEXIO_UART_RxDataRegFullFlag does/doesn't trigger the DMA request.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
enable	True to enable, false to disable.

static void FLEXIO_UART_Enable	(	FLEXIO_UART_Type *	base,
		bool	enable
	)

inlinestatic

Parameters

base	Pointer to the FLEXIO_UART_Type.
enable	True to enable, false does not have any effect.

static void FLEXIO_UART_WriteByte	(	FLEXIO_UART_Type *	base,
		const uint8_t *	buffer
	)

inlinestatic

Note: This is a non-blocking API, which returns directly after the data is put into the data register. Ensure that the TxEmptyFlag is asserted before calling this API.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
buffer	The data bytes to send.

static void FLEXIO_UART_ReadByte	(	FLEXIO_UART_Type *	base,
		uint8_t *	buffer
	)

inlinestatic

Note: This is a non-blocking API, which returns directly after the data is read from the data register. Ensure that the RxFullFlag is asserted before calling this API.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
buffer	The buffer to store the received bytes.

void FLEXIO_UART_WriteBlocking	(	FLEXIO_UART_Type *	base,
		const uint8_t *	txData,
		size_t	txSize
	)

Note: This function blocks using the polling method until all bytes have been sent.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
txData	The data bytes to send.
txSize	The number of data bytes to send.

void FLEXIO_UART_ReadBlocking	(	FLEXIO_UART_Type *	base,
		uint8_t *	rxData,
		size_t	rxSize
	)

Note: This function blocks using the polling method until all bytes have been received.

Parameters

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

status_t FLEXIO_UART_TransferCreateHandle	(	FLEXIO_UART_Type *	base,
		flexio_uart_handle_t *	handle,
		flexio_uart_transfer_callback_t	callback,
		void *	userData
	)

This function initializes the FlexIO UART handle, which can be used for other FlexIO UART transactional APIs. Call this API once to get the initialized handle.

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

Parameters

base	to FLEXIO_UART_Type structure.
handle	Pointer to the flexio_uart_handle_t structure to store the transfer state.
callback	The callback function.
userData	The parameter of the callback function.

Return values

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

void FLEXIO_UART_TransferStartRingBuffer	(	FLEXIO_UART_Type *	base,
		flexio_uart_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_ReceiveNonBlocking() API. If there is already data received in the ring buffer, users can get the received data from the ring buffer directly.

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

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
handle	Pointer to the flexio_uart_handle_t structure to store the transfer state.
ringBuffer	Start address of ring buffer for background receiving. Pass NULL to disable the ring buffer.
ringBufferSize	Size of the ring buffer.

void FLEXIO_UART_TransferStopRingBuffer	(	FLEXIO_UART_Type *	base,
		flexio_uart_handle_t *	handle
	)

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

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
handle	Pointer to the flexio_uart_handle_t structure to store the transfer state.

status_t FLEXIO_UART_TransferSendNonBlocking	(	FLEXIO_UART_Type *	base,
		flexio_uart_handle_t *	handle,
		flexio_uart_transfer_t *	xfer
	)

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

Note: The kStatus_FLEXIO_UART_TxIdle is passed to the upper layer when all data is written to the TX register. However, it does not ensure that all data is sent out.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
handle	Pointer to the flexio_uart_handle_t structure to store the transfer state.
xfer	FlexIO UART transfer structure. See flexio_uart_transfer_t.

Return values

kStatus_Success	Successfully starts the data transmission.
kStatus_UART_TxBusy	Previous transmission still not finished, data not written to the TX register.

void FLEXIO_UART_TransferAbortSend	(	FLEXIO_UART_Type *	base,
		flexio_uart_handle_t *	handle
	)

This function aborts the interrupt-driven data sending. Get the remainBytes to find out how many bytes are still not sent out.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
handle	Pointer to the flexio_uart_handle_t structure to store the transfer state.

status_t FLEXIO_UART_TransferGetSendCount	(	FLEXIO_UART_Type *	base,
		flexio_uart_handle_t *	handle,
		size_t *	count
	)

This function gets the number of bytes sent driven by interrupt.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
handle	Pointer to the flexio_uart_handle_t structure to store the transfer state.
count	Number of bytes sent so far by the non-blocking transaction.

Return values

kStatus_NoTransferInProgress	transfer has finished or no transfer in progress.
kStatus_Success	Successfully return the count.

status_t FLEXIO_UART_TransferReceiveNonBlocking	(	FLEXIO_UART_Type *	base,
		flexio_uart_handle_t *	handle,
		flexio_uart_transfer_t *	xfer,
		size_t *	receivedBytes
	)

This function receives data using the interrupt method. This is a non-blocking function, which returns without waiting for all data to be received. If the RX ring buffer is used and not empty, the data in ring buffer is copied and the parameter receivedBytes shows how many bytes are copied from the ring buffer. After copying, if the data in ring buffer is not enough to read, the receive request is saved by the UART driver. When new data arrives, the receive request is serviced first. When all data is received, the UART driver notifies the upper layer through a callback function and passes the status parameter kStatus_UART_RxIdle. For example, if the upper layer needs 10 bytes but there are only 5 bytes in the ring buffer, the 5 bytes are copied to xfer->data. This function returns with the parameter receivedBytes set to 5. For the last 5 bytes, newly arrived data is saved from the xfer->data[5]. When 5 bytes are received, the UART driver notifies 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	Pointer to the FLEXIO_UART_Type structure.
handle	Pointer to the flexio_uart_handle_t structure to store the transfer state.
xfer	UART transfer structure. See flexio_uart_transfer_t.
receivedBytes	Bytes received from the ring buffer directly.

Return values

kStatus_Success	Successfully queue the transfer into the transmit queue.
kStatus_FLEXIO_UART_RxBusy	Previous receive request is not finished.

void FLEXIO_UART_TransferAbortReceive	(	FLEXIO_UART_Type *	base,
		flexio_uart_handle_t *	handle
	)

This function aborts the receive data which was using IRQ.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
handle	Pointer to the flexio_uart_handle_t structure to store the transfer state.

status_t FLEXIO_UART_TransferGetReceiveCount	(	FLEXIO_UART_Type *	base,
		flexio_uart_handle_t *	handle,
		size_t *	count
	)

This function gets the number of bytes received driven by interrupt.

Parameters

base	Pointer to the FLEXIO_UART_Type structure.
handle	Pointer to the flexio_uart_handle_t structure to store the transfer state.
count	Number of bytes received so far by the non-blocking transaction.

Return values

kStatus_NoTransferInProgress	transfer has finished or no transfer in progress.
kStatus_Success	Successfully return the count.

void FLEXIO_UART_TransferHandleIRQ	(	void *	uartType,
		void *	uartHandle
	)

This function processes the FlexIO UART transmit and receives the IRQ request.

Parameters

uartType	Pointer to the FLEXIO_UART_Type structure.
uartHandle	Pointer to the flexio_uart_handle_t structure to store the transfer state.

Overview

Typical use case

FlexIO UART send/receive using a polling method

FlexIO UART send/receive using an interrupt method

FlexIO UART receive using the ringbuffer feature

FlexIO UART send/receive using a DMA method

Modules

Data Structures

Typedefs

Enumerations

Driver version

Initialization and deinitialization

Status

Interrupts

DMA Control

Bus Operations

Transactional

Data Structure Documentation

Data Fields

Field Documentation

Data Fields

Field Documentation

Data Fields

Data Fields

Field Documentation

Macro Definition Documentation

Typedef Documentation

Enumeration Type Documentation

Function Documentation