UARTDRV - UART Driver

Description

Universal Asynchronous Receiver/Transmitter Driver.

The source files for the UART driver library, uartdrv.c and uartdrv.h, are in the emdrv/uartdrv folder.


Introduction

The UART driver supports the UART capabilities of the USART, UART, and LEUART peripherals. The driver is fully reentrant and supports multiple driver instances. The driver does not buffer or queue data. However, it queues UART transmit and receive operations. Both blocking and non-blocking transfer functions are available. Non-blocking transfer functions report transfer completion with callback functions. Transfers are done using DMA. Simple direct/forced transmit and receive functions are also available. Note that these functions are blocking and not suitable for low energy applications because they use CPU polling.

UART hardware flow control (CTS/RTS) is fully supported by the driver. UART software flow control (XON/XOFF) is partially supported by the driver. For more information about flow control support, see Flow Control Support.

Note
Transfer completion callback functions are called from within the DMA interrupt handler with interrupts disabled.


Configuration Options

Some properties of the UARTDRV driver are compile-time configurable. These properties are set in a uartdrv_config.h file. A template for this file, containing default values, is in the emdrv/config folder. To configure UARTDRV for your application, provide a custom configuration file, or override the defines on the compiler command line. These are the available configuration parameters with default values defined.

// Set to 1 to enable hardware flow control.
#define EMDRV_UARTDRV_FLOW_CONTROL_ENABLE 1
// Maximum number of driver instances.
#define EMDRV_UARTDRV_MAX_DRIVER_INSTANCES 4
// UART software flow control code: request peer to start Tx.
#define UARTDRV_FC_SW_XON 0x11
// UART software flow control code: request peer to stop Tx.
#define UARTDRV_FC_SW_XOFF 0x13

The properties of each UART driver instance are set at run-time via the UARTDRV_InitUart_t data structure input parameter to the UARTDRV_InitUart() function for UART and USART peripherals, and the UARTDRV_InitLeuart_t data structure input parameter to the UARTDRV_InitLeuart() function for LEUART peripherals.


The API

This section contains brief descriptions of the functions in the API. For more information on input and output parameters and return values, click on the hyperlinked function names. Most functions return an error code, ECODE_EMDRV_UARTDRV_OK is returned on success, see ecode.h and uartdrv.h for other error codes.

The application code must include uartdrv.h header file.

UARTDRV_InitUart(), UARTDRV_InitLeuart() and UARTDRV_DeInit()
These functions initialize and deinitialize the UARTDRV driver. Typically, UARTDRV_InitUart() (for UART/USART) or UARTDRV_InitLeuart() (for LEUART) are called once in the startup code.

UARTDRV_GetReceiveStatus() and UARTDRV_GetTransmitStatus()
Query the status of a current transmit or receive operations. Reports number of items (frames) transmitted and remaining.

UARTDRV_GetReceiveDepth() and UARTDRV_GetTransmitDepth()
Get the number of queued receive or transmit operations.

UARTDRV_Transmit(), UARTDRV_Receive()
UARTDRV_TransmitB(), UARTDRV_ReceiveB()
UARTDRV_ForceTransmit() and UARTDRV_ForceReceive()
Blocking and non-blocking transfer functions are included. The blocking versions have an uppercase B (for Blocking) at the end of their function name. Blocking functions do not return before the transfer is complete. The non-blocking functions signal a transfer completion with a callback function. UARTDRV_ForceTransmit() and UARTDRV_ForceReceive() are also blocking. These two functions access the UART peripheral directly without using DMA or interrupts. UARTDRV_ForceTransmit() does not respect flow control. UARTDRV_ForceReceive() forces RTS low.

UARTDRV_Abort()
Abort current transmit or receive operations and remove all queued operations.

UARTDRV_FlowControlSet(), UARTDRV_FlowControlGetSelfStatus(), UARTDRV_FlowControlSetPeerStatus() and UARTDRV_FlowControlGetPeerStatus()
Set and get flow control status of self or peer device. Note that the return value from these two functions depends on the flow control mode set by UARTDRV_FlowControlSet(), UARTDRV_InitUart(), or UARTDRV_InitLeuart().

UARTDRV_FlowControlIgnoreRestrain()
Enables transmission when restrained by flow control.

UARTDRV_PauseTransmit() and UARTDRV_ResumeTransmit()
Pause a currently active transmit operation by preventing the DMA from loading the UART FIFO. Will not override HW flow control state (if applicable), but can be used in conjunction.


Flow Control Support

If UART flow control is not required, make sure that EMDRV_UARTDRV_FLOW_CONTROL_ENABLE is set to 0. This reduces the code size and complexity of the driver.

Both hardware and software flow control are supported. To enable either of these, set EMDRV_UARTDRV_FLOW_CONTROL_ENABLE to 1 in uartdrv_config.h.


Hardware Flow Control

UART hardware flow control uses two additional pins for flow control handshaking, the clear-to-send (CTS) and ready-to-send (RTS) pins. RTS is an output and CTS is an input. These are active-low signals. When CTS is high, the UART transmitter should stop sending frames. A receiver should set RTS high when it is no longer capable of receiving data.

Peripheral Hardware Flow Control

Newer devices natively support CTS/RTS in the USART peripheral hardware. To enable hardware flow control, perform the following steps:

  • Set EMDRV_UARTDRV_FLOW_CONTROL_ENABLE to 1.
  • In the UARTDRV_InitUart_t struct passed to UARTDRV_InitUart(), set UARTDRV_InitUart_t.fcType = uartdrvFlowControlHwUart.
  • Define the pins for CTS and RTS by setting ctsPort, ctsPin, rtsPort and rtsPin in the init struct.
  • Also define the CTS and RTS locations by setting portLocationCts and portLocationRts in the init struct.
GPIO Hardware Flow Control

To support hardware flow control on devices that don't have UART CTS/RTS hardware support, the driver includes the GPIOINT driver to emulate a hardware implementation of UART CTS/RTS flow control on these devices.

To enable hardware flow control, perform the following steps:

  • Set EMDRV_UARTDRV_FLOW_CONTROL_ENABLE to 1.
  • UART/USART: In the UARTDRV_InitUart_t struct passed to UARTDRV_InitUart(), set UARTDRV_InitUart_t.fcType = uartdrvFlowControlHw.
  • LEUART: In the UARTDRV_InitLeuart_t struct passed to UARTDRV_InitLeuart(), set UARTDRV_InitLeuart_t::fcType = uartdrvFlowControlHw.
  • Define the pins for CTS and RTS by setting ctsPort, ctsPin, rtsPort and rtsPin in the same init struct.
Note
Because of the limitations in GPIO interrupt hardware, you cannot select CTS pins in multiple driver instances with the same pin number. For example, pin A0 and B0 cannot serve as CTS pins in two concurrent driver instances.

RTS is set high whenever there are no Rx operations queued. The UART transmitter is halted when the CTS pin goes high. The transmitter completes the current frame before halting. DMA transfers are also halted.


Software Flow Control

UART software flow control uses in-band signaling, meaning the receiver sends special flow control characters to the transmitter and thereby removes the need for dedicated wires for flow control. The two symbols UARTDRV_FC_SW_XON and UARTDRV_FC_SW_XOFF are defined in uartdrv_config.h.

To enable support for software flow control, perform the following steps:

Note
Software flow control is partial only.

The application must monitor buffers and make decisions on when to send XON/ XOFF. XON/XOFF can be sent to the peer using UARTDRV_FlowControlSet(). Though UARTDRV_FlowControlSet() will pause the active transmit operation to send a flow control character, there is no way to guarantee the order. If the application implements a specific packet format where the flow control codes may appear only in fixed positions, the application should not use UARTDRV_FlowControlSet() but implement read and write of XON/XOFF into packet buffers. If the application code fully implements all the flow control logic, EMDRV_UARTDRV_FLOW_CONTROL_ENABLE should be set to 0 to reduce code space.


Example

Modules

Error Codes
 
Status Codes
 

Data Structures

struct  UARTDRV_Buffer_t
 UART transfer buffer.
 
struct  UARTDRV_Buffer_FifoQueue_t
 Transfer operation FIFO queue typedef.
 
struct  UARTDRV_InitLeuart_t
 LEUART driver instance initialization structure.
 
struct  UARTDRV_InitEuart_t
 UART driver instance initialization structure.
 
struct  UARTDRV_HandleData
 A UART driver instance handle data structure.
 

Functions

Ecode_t UARTDRV_InitLeuart (UARTDRV_Handle_t handle, const UARTDRV_InitLeuart_t *initData)
 Initialize a LEUART driver instance.
 
Ecode_t UARTDRV_InitEuart (UARTDRV_Handle_t handle, const UARTDRV_InitEuart_t *initData)
 Initialize a EUART driver instance.
 
Ecode_t UARTDRV_DeInit (UARTDRV_Handle_t handle)
 Deinitialize a UART driver instance.
 
UARTDRV_Status_t UARTDRV_GetPeripheralStatus (UARTDRV_Handle_t handle)
 Return the status of the UART peripheral associated with a given handle.
 
UARTDRV_Status_t UARTDRV_GetReceiveStatus (UARTDRV_Handle_t handle, uint8_t **buffer, UARTDRV_Count_t *bytesReceived, UARTDRV_Count_t *bytesRemaining)
 Check the status of the UART and gather information about any ongoing receive operations.
 
UARTDRV_Status_t UARTDRV_GetTransmitStatus (UARTDRV_Handle_t handle, uint8_t **buffer, UARTDRV_Count_t *bytesSent, UARTDRV_Count_t *bytesRemaining)
 Check the status of the UART and gather information about any ongoing transmit operations.
 
uint8_t UARTDRV_GetReceiveDepth (UARTDRV_Handle_t handle)
 Return the number of queued receive operations.
 
uint8_t UARTDRV_GetTransmitDepth (UARTDRV_Handle_t handle)
 Returns the number of queued transmit operations.
 
Ecode_t UARTDRV_Transmit (UARTDRV_Handle_t handle, uint8_t *data, UARTDRV_Count_t count, UARTDRV_Callback_t callback)
 Start a non-blocking transmit.
 
Ecode_t UARTDRV_Receive (UARTDRV_Handle_t handle, uint8_t *data, UARTDRV_Count_t count, UARTDRV_Callback_t callback)
 Start a non-blocking receive.
 
Ecode_t UARTDRV_TransmitB (UARTDRV_Handle_t handle, uint8_t *data, UARTDRV_Count_t count)
 Start a blocking transmit.
 
Ecode_t UARTDRV_ReceiveB (UARTDRV_Handle_t handle, uint8_t *data, UARTDRV_Count_t count)
 Start a blocking receive.
 
Ecode_t UARTDRV_ForceTransmit (UARTDRV_Handle_t handle, uint8_t *data, UARTDRV_Count_t count)
 Direct transmit without interrupts or callback.
 
UARTDRV_Count_t UARTDRV_ForceReceive (UARTDRV_Handle_t handle, uint8_t *data, UARTDRV_Count_t maxLength)
 Direct receive without interrupts or callback.
 
Ecode_t UARTDRV_Abort (UARTDRV_Handle_t handle, UARTDRV_AbortType_t type)
 Abort ongoing UART transfers.
 
Ecode_t UARTDRV_PauseTransmit (UARTDRV_Handle_t handle)
 Pause an ongoing transmit operation.
 
Ecode_t UARTDRV_ResumeTransmit (UARTDRV_Handle_t handle)
 Resume a paused transmit operation.
 
UARTDRV_FlowControlState_t UARTDRV_FlowControlGetSelfStatus (UARTDRV_Handle_t handle)
 Check the self flow control status.
 
UARTDRV_FlowControlState_t UARTDRV_FlowControlGetPeerStatus (UARTDRV_Handle_t handle)
 Check the peer's flow control status.
 
Ecode_t UARTDRV_FlowControlSet (UARTDRV_Handle_t handle, UARTDRV_FlowControlState_t state)
 Set UART flow control state.
 
Ecode_t UARTDRV_FlowControlSetPeerStatus (UARTDRV_Handle_t handle, UARTDRV_FlowControlState_t state)
 Set peer UART flow control state.
 
Ecode_t UARTDRV_FlowControlIgnoreRestrain (UARTDRV_Handle_t handle)
 Enable transmission when restrained by flow control.
 

Macros

#define DEFINE_BUF_QUEUE(qSize, qName)
 Macros to define FIFO and buffer queues.
 

Typedefs

typedef uint32_t UARTDRV_Count_t
 A UART transfer count.
 
typedef uint32_t UARTDRV_Status_t
 A UART status return type. Bitfield of UARTDRV_STATUS_* values.
 
typedef void(* UARTDRV_Callback_t) (struct UARTDRV_HandleData *handle, Ecode_t transferStatus, uint8_t *data, UARTDRV_Count_t transferCount)
 UARTDRV transfer completion callback function.
 
typedef UARTDRV_HandleData_t * UARTDRV_Handle_t
 Handle pointer.
 

Enumerations

enum  UARTDRV_FlowControlType {
  uartdrvFlowControlNone = 0,
  uartdrvFlowControlSw = 1,
  uartdrvFlowControlHw = 2,
  uartdrvFlowControlHwUart = 3
}
 Flow Control method.
 
enum  UARTDRV_FlowControlState {
  uartdrvFlowControlOn = 0,
  uartdrvFlowControlOff = 1,
  uartdrvFlowControlAuto = 2
}
 Flow Control state.
 
enum  UARTDRV_AbortType {
  uartdrvAbortTransmit = 1,
  uartdrvAbortReceive = 2,
  uartdrvAbortAll = 3
}
 Transfer abort type.
 

Function Documentation

◆ UARTDRV_InitLeuart()

Ecode_t UARTDRV_InitLeuart ( UARTDRV_Handle_t  handle,
const UARTDRV_InitLeuart_t initData 
)

Initialize a LEUART driver instance.

Parameters
[out]handlePointer to a UARTDRV handle, refer to UARTDRV_Handle_t.
[in]initDataPointer to an initialization data structure, refer to UARTDRV_InitLeuart_t.
Returns
ECODE_EMDRV_UARTDRV_OK on success. On failure, an appropriate UARTDRV Ecode_t is returned.

◆ UARTDRV_InitEuart()

Ecode_t UARTDRV_InitEuart ( UARTDRV_Handle_t  handle,
const UARTDRV_InitEuart_t initData 
)

Initialize a EUART driver instance.

Parameters
[out]handlePointer to a UARTDRV handle, refer to UARTDRV_Handle_t.
[in]initDataPointer to an initialization data structure, refer to UARTDRV_InitEuart_t.
Returns
ECODE_EMDRV_UARTDRV_OK on success. On failure an appropriate UARTDRV Ecode_t is returned.

◆ UARTDRV_DeInit()

Ecode_t UARTDRV_DeInit ( UARTDRV_Handle_t  handle)

Deinitialize a UART driver instance.

Parameters
[in]handlePointer to a UART driver handle.
Returns
ECODE_EMDRV_UARTDRV_OK on success. On failure, an appropriate UARTDRV Ecode_t is returned.

◆ UARTDRV_GetPeripheralStatus()

UARTDRV_Status_t UARTDRV_GetPeripheralStatus ( UARTDRV_Handle_t  handle)

Return the status of the UART peripheral associated with a given handle.

Parameters
[in]handlePointer to a UART driver handle.
Returns
UART status value

◆ UARTDRV_GetReceiveStatus()

UARTDRV_Status_t UARTDRV_GetReceiveStatus ( UARTDRV_Handle_t  handle,
uint8_t **  buffer,
UARTDRV_Count_t itemsReceived,
UARTDRV_Count_t itemsRemaining 
)

Check the status of the UART and gather information about any ongoing receive operations.

Parameters
[in]handlePointer to a UART driver handle.
[out]bufferPointer to the current data buffer.
[out]itemsReceivedCurrent bytes received count.
[out]itemsRemainingCurrent bytes remaining count.
Returns
UART status.

◆ UARTDRV_GetTransmitStatus()

UARTDRV_Status_t UARTDRV_GetTransmitStatus ( UARTDRV_Handle_t  handle,
uint8_t **  buffer,
UARTDRV_Count_t itemsSent,
UARTDRV_Count_t itemsRemaining 
)

Check the status of the UART and gather information about any ongoing transmit operations.

Parameters
[in]handlePointer to a UART driver handle.
[out]bufferPointer to the current data buffer.
[out]itemsSentCurrent bytes sent count.
[out]itemsRemainingCurrent bytes remaining count.
Returns
UART status.

◆ UARTDRV_GetReceiveDepth()

uint8_t UARTDRV_GetReceiveDepth ( UARTDRV_Handle_t  handle)

Return the number of queued receive operations.

Parameters
[in]handlePointer to a UART driver handle.
Returns
The number of queued operations.

◆ UARTDRV_GetTransmitDepth()

uint8_t UARTDRV_GetTransmitDepth ( UARTDRV_Handle_t  handle)

Returns the number of queued transmit operations.

Parameters
[in]handlePointer to a UART driver handle.
Returns
The number of queued operations.

◆ UARTDRV_Transmit()

Ecode_t UARTDRV_Transmit ( UARTDRV_Handle_t  handle,
uint8_t *  data,
UARTDRV_Count_t  count,
UARTDRV_Callback_t  callback 
)

Start a non-blocking transmit.

Parameters
[in]handlePointer to a UART driver handle.
[in]dataA transmit data buffer.
[in]countA number of bytes to transmit.
[in]callbackA transfer completion callback.
Returns
ECODE_EMDRV_UARTDRV_OK on success.

◆ UARTDRV_Receive()

Ecode_t UARTDRV_Receive ( UARTDRV_Handle_t  handle,
uint8_t *  data,
UARTDRV_Count_t  count,
UARTDRV_Callback_t  callback 
)

Start a non-blocking receive.

Parameters
[in]handlePointer to a UART driver handle.
[in]dataA receive data buffer.
[in]countA number of bytes received.
[in]callbackA transfer completion callback.
Returns
ECODE_EMDRV_UARTDRV_OK on success.

◆ UARTDRV_TransmitB()

Ecode_t UARTDRV_TransmitB ( UARTDRV_Handle_t  handle,
uint8_t *  data,
UARTDRV_Count_t  count 
)

Start a blocking transmit.

Parameters
[in]handlePointer to a UART driver handle.
[in]dataA transmit data buffer.
[in]countA number of bytes to transmit.
Returns
ECODE_EMDRV_UARTDRV_OK on success.

◆ UARTDRV_ReceiveB()

Ecode_t UARTDRV_ReceiveB ( UARTDRV_Handle_t  handle,
uint8_t *  data,
UARTDRV_Count_t  count 
)

Start a blocking receive.

Parameters
[in]handlePointer to a UART driver handle.
[in]dataA receive data buffer.
[in]countA number of bytes received.
Returns
ECODE_EMDRV_UARTDRV_OK on success.

◆ UARTDRV_ForceTransmit()

Ecode_t UARTDRV_ForceTransmit ( UARTDRV_Handle_t  handle,
uint8_t *  data,
UARTDRV_Count_t  count 
)

Direct transmit without interrupts or callback.

This is a blocking function. that ignores flow control if enabled.

Parameters
[in]handlePointer to a UART driver handle.
[in]dataPointer to the buffer.
[in]countA number of bytes to transmit.
Returns
ECODE_EMDRV_UARTDRV_OK on success.

◆ UARTDRV_ForceReceive()

UARTDRV_Count_t UARTDRV_ForceReceive ( UARTDRV_Handle_t  handle,
uint8_t *  data,
UARTDRV_Count_t  maxCount 
)

Direct receive without interrupts or callback.

This is a blocking function.

Parameters
[in]handlePointer to a UART driver handle.
[in]datapointer to buffer.
[in]maxCountMaximum number of bytes to receive.
Returns
Number of bytes received.

◆ UARTDRV_Abort()

Ecode_t UARTDRV_Abort ( UARTDRV_Handle_t  handle,
UARTDRV_AbortType_t  type 
)

Abort ongoing UART transfers.

All ongoing or queued operations of the given abort type will be aborted.

Parameters
[in]handlePointer to a UART driver handle.
[in]typeAbort type – whether to abort only Tx, only Rx, or both.
Returns
ECODE_EMDRV_UARTDRV_OK on success, ECODE_EMDRV_UARTDRV_IDLE if the UART is idle. On failure, an appropriate UARTDRV Ecode_t is returned.

◆ UARTDRV_PauseTransmit()

Ecode_t UARTDRV_PauseTransmit ( UARTDRV_Handle_t  handle)

Pause an ongoing transmit operation.

Parameters
[in]handlePointer to a UART driver handle.
Returns
ECODE_EMDRV_UARTDRV_OK on success. On failure, an appropriate UARTDRV Ecode_t is returned.

◆ UARTDRV_ResumeTransmit()

Ecode_t UARTDRV_ResumeTransmit ( UARTDRV_Handle_t  handle)

Resume a paused transmit operation.

Parameters
[in]handlePointer to a UART driver handle.
Returns
ECODE_EMDRV_UARTDRV_OK on success. On failure, an appropriate UARTDRV Ecode_t is returned.

◆ UARTDRV_FlowControlGetSelfStatus()

UARTDRV_FlowControlState_t UARTDRV_FlowControlGetSelfStatus ( UARTDRV_Handle_t  handle)

Check the self flow control status.

Parameters
[in]handlePointer to a UART driver handle.
Returns
Returns uartdrvFlowControlOn if requesting to send.

◆ UARTDRV_FlowControlGetPeerStatus()

UARTDRV_FlowControlState_t UARTDRV_FlowControlGetPeerStatus ( UARTDRV_Handle_t  handle)

Check the peer's flow control status.

Parameters
[in]handlePointer to a UART driver handle.
Returns
Returns uartdrvFlowControlOn if clear to send.

◆ UARTDRV_FlowControlSet()

Ecode_t UARTDRV_FlowControlSet ( UARTDRV_Handle_t  handle,
UARTDRV_FlowControlState_t  state 
)

Set UART flow control state.

Set nRTS pin if hardware flow control is enabled. Send XON/XOFF if software flow control is enabled.

Parameters
[in]handlePointer to a UART driver handle.
[in]stateFlow control state.
Returns
ECODE_EMDRV_UARTDRV_OK on success.

◆ UARTDRV_FlowControlSetPeerStatus()

Ecode_t UARTDRV_FlowControlSetPeerStatus ( UARTDRV_Handle_t  handle,
UARTDRV_FlowControlState_t  state 
)

Set peer UART flow control state.

Pause/resume transmit accordingly. Only for manual software flow control.

Parameters
[in]handlePointer to a UART driver handle.
[in]stateFlow control state.
Returns
ECODE_EMDRV_UARTDRV_OK on success.

◆ UARTDRV_FlowControlIgnoreRestrain()

Ecode_t UARTDRV_FlowControlIgnoreRestrain ( UARTDRV_Handle_t  handle)

Enable transmission when restrained by flow control.

Parameters
[in]handlePointer to a UART driver handle.
Returns
ECODE_EMDRV_UARTDRV_OK on success.

Macro Definition Documentation

◆ DEFINE_BUF_QUEUE

#define DEFINE_BUF_QUEUE (   qSize,
  qName 
)
Value:
typedef struct { \
uint16_t head; \
uint16_t tail; \
volatile uint16_t used; \
const uint16_t size; \
UARTDRV_Buffer_t fifo[qSize]; \
} _##qName; \
static volatile _##qName qName = \
{ \
.head = 0, \
.tail = 0, \
.used = 0, \
.size = qSize, \
}

Macros to define FIFO and buffer queues.

typedef can't be used because the size of the FIFO array in the queues can change.

Typedef Documentation

◆ UARTDRV_Count_t

typedef uint32_t UARTDRV_Count_t

A UART transfer count.

◆ UARTDRV_Status_t

typedef uint32_t UARTDRV_Status_t

A UART status return type. Bitfield of UARTDRV_STATUS_* values.

◆ UARTDRV_Callback_t

typedef void(* UARTDRV_Callback_t) (struct UARTDRV_HandleData *handle, Ecode_t transferStatus, uint8_t *data, UARTDRV_Count_t transferCount)

UARTDRV transfer completion callback function.

Called when a transfer is complete. An application should check the transferStatus and itemsTransferred values.

Parameters
[in]handleThe UARTDRV device handle used to start the transfer.
[in]transferStatusCompletion status of the transfer operation.
[in]dataA pointer to the transfer data buffer.
[in]transferCountA number of bytes transferred.

◆ UARTDRV_Handle_t

typedef UARTDRV_HandleData_t* UARTDRV_Handle_t

Handle pointer.

Enumeration Type Documentation

◆ UARTDRV_FlowControlType

Flow Control method.

Enumerator
uartdrvFlowControlNone 

None.

uartdrvFlowControlSw 

Software XON/XOFF.

uartdrvFlowControlHw 

nRTS/nCTS hardware handshake

uartdrvFlowControlHwUart 

UART peripheral controls nRTS/nCTS.

◆ UARTDRV_FlowControlState

Flow Control state.

Enumerator
uartdrvFlowControlOn 

XON or nRTS/nCTS low.

uartdrvFlowControlOff 

XOFF or nRTS/nCTS high.

uartdrvFlowControlAuto 

This driver controls the state.

◆ UARTDRV_AbortType

Transfer abort type.

Enumerator
uartdrvAbortTransmit 

Abort current and queued transmit operations.

uartdrvAbortReceive 

Abort current and queued receive operations.

uartdrvAbortAll 

Abort all current and queued operations.