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Public Member Functions | Protected Member Functions
Serial Class Referenceabstract

A serial port (UART) for communication with other serial devices. More...

#include <Serial.h>

Inheritance diagram for Serial:
SerialBase Stream NonCopyable< Serial > NonCopyable< SerialBase > FileLike NonCopyable< Stream > FileHandle FileBase NonCopyable< FileLike > NonCopyable< FileHandle > NonCopyable< FileBase >

Public Member Functions

 Serial (PinName tx, PinName rx, const char *name=NULL, int baud=MBED_CONF_PLATFORM_DEFAULT_SERIAL_BAUD_RATE)
 Create a Serial port, connected to the specified transmit and receive pins. More...
 
 Serial (PinName tx, PinName rx, int baud)
 Create a Serial port, connected to the specified transmit and receive pins, with the specified baud. More...
 
void baud (int baudrate)
 Set the baud rate of the serial port. More...
 
void format (int bits=8, Parity parity=SerialBase::None, int stop_bits=1)
 Set the transmission format used by the serial port. More...
 
void attach (Callback< void()> func, IrqType type=RxIrq)
 Attach a function to call whenever a serial interrupt is generated. More...
 
template<typename T >
void attach (T *obj, void(T::*method)(), IrqType type=RxIrq)
 Attach a member function to call whenever a serial interrupt is generated. More...
 
template<typename T >
void attach (T *obj, void(*method)(T *), IrqType type=RxIrq)
 Attach a member function to call whenever a serial interrupt is generated. More...
 
void set_break ()
 Generate a break condition on the serial line NOTE: Clear break needs to run at least one frame after set_break is called. More...
 
void clear_break ()
 Clear a break condition on the serial line NOTE: Should be run at least one frame after set_break is called. More...
 
void send_break ()
 Generate a break condition on the serial line. More...
 
void set_flow_control (Flow type, PinName flow1=NC, PinName flow2=NC)
 Set the flow control type on the serial port. More...
 
int write (const uint8_t *buffer, int length, const event_callback_t &callback, int event=SERIAL_EVENT_TX_COMPLETE)
 Begin asynchronous write using 8bit buffer. More...
 
int write (const uint16_t *buffer, int length, const event_callback_t &callback, int event=SERIAL_EVENT_TX_COMPLETE)
 Begin asynchronous write using 16bit buffer. More...
 
void abort_write ()
 Abort the on-going write transfer. More...
 
int read (uint8_t *buffer, int length, const event_callback_t &callback, int event=SERIAL_EVENT_RX_COMPLETE, unsigned char char_match=SERIAL_RESERVED_CHAR_MATCH)
 Begin asynchronous reading using 8bit buffer. More...
 
int read (uint16_t *buffer, int length, const event_callback_t &callback, int event=SERIAL_EVENT_RX_COMPLETE, unsigned char char_match=SERIAL_RESERVED_CHAR_MATCH)
 Begin asynchronous reading using 16bit buffer. More...
 
void abort_read ()
 Abort the on-going read transfer. More...
 
int set_dma_usage_tx (DMAUsage usage)
 Configure DMA usage suggestion for non-blocking TX transfers. More...
 
int set_dma_usage_rx (DMAUsage usage)
 Configure DMA usage suggestion for non-blocking RX transfers. More...
 
virtual int truncate (off_t length)
 Truncate or extend a file. More...
 
virtual off_t lseek (off_t offset, int whence)
 Move the file position to a given offset from a given location. More...
 
virtual int fsync ()
 Flush any buffers associated with the FileHandle, ensuring it is up to date on disk. More...
 
virtual off_t flen ()
 Find the length of the file. More...
 
virtual int set_blocking (bool blocking)
 Set blocking or nonblocking mode of the file operation like read/write. More...
 
virtual bool is_blocking () const
 Check current blocking or nonblocking mode for file operations. More...
 
virtual int enable_input (bool enabled)
 Enable or disable input. More...
 
virtual int enable_output (bool enabled)
 Enable or disable output. More...
 
virtual short poll (short events) const
 Check for poll event flags You can use or ignore the input parameter. More...
 
bool writable () const
 Definition depends on the subclass implementing FileHandle. More...
 
bool readable () const
 Definition depends on the subclass implementing FileHandle. More...
 
virtual void sigio (Callback< void()> func)
 Register a callback on state change of the file. More...
 

Protected Member Functions

virtual int close ()
 Close a file. More...
 
virtual ssize_t write (const void *buffer, size_t length)
 Write the contents of a buffer to a file. More...
 
virtual ssize_t read (void *buffer, size_t length)
 Read the contents of a file into a buffer. More...
 
virtual off_t seek (off_t offset, int whence)
 Move the file position to a given offset from from a given location. More...
 
virtual off_t tell ()
 Get the file position of the file. More...
 
virtual void rewind ()
 Rewind the file position to the beginning of the file. More...
 
virtual int isatty ()
 Check if the file in an interactive terminal device. More...
 
virtual int sync ()
 Flush any buffers associated with the file. More...
 
virtual off_t size ()
 Get the size of the file. More...
 
virtual void lock ()
 Acquire exclusive access to this object. More...
 
virtual void unlock ()
 Release exclusive access to this object. More...
 

Detailed Description

A serial port (UART) for communication with other serial devices.

Can be used for Full Duplex communication, or Simplex by specifying one pin as NC (Not Connected)

Note
Synchronization level: Thread safe

Example:

// Print "Hello World" to the PC
#include "mbed.h"
Serial pc(USBTX, USBRX);
int main() {
pc.printf("Hello World\n");
}

Definition at line 54 of file Serial.h.

Constructor & Destructor Documentation

Serial ( PinName  tx,
PinName  rx,
const char *  name = NULL,
int  baud = MBED_CONF_PLATFORM_DEFAULT_SERIAL_BAUD_RATE 
)

Create a Serial port, connected to the specified transmit and receive pins.

Parameters
txTransmit pin
rxReceive pin
nameThe name of the stream associated with this serial port (optional)
baudThe baud rate of the serial port (optional, defaults to MBED_CONF_PLATFORM_DEFAULT_SERIAL_BAUD_RATE or 9600)
Note
Either tx or rx may be specified as NC (Not Connected) if unused
Serial ( PinName  tx,
PinName  rx,
int  baud 
)

Create a Serial port, connected to the specified transmit and receive pins, with the specified baud.

Parameters
txTransmit pin
rxReceive pin
baudThe baud rate of the serial port
Note
Either tx or rx may be specified as NC (Not Connected) if unused

Member Function Documentation

void abort_read ( )
inherited

Abort the on-going read transfer.

void abort_write ( )
inherited

Abort the on-going write transfer.

void attach ( Callback< void()>  func,
IrqType  type = RxIrq 
)
inherited

Attach a function to call whenever a serial interrupt is generated.

Parameters
funcA pointer to a void function, or 0 to set as none
typeWhich serial interrupt to attach the member function to (Serial::RxIrq for receive, TxIrq for transmit buffer empty)
void attach ( T *  obj,
void(T::*)()  method,
IrqType  type = RxIrq 
)
inherited

Attach a member function to call whenever a serial interrupt is generated.

Parameters
objpointer to the object to call the member function on
methodpointer to the member function to be called
typeWhich serial interrupt to attach the member function to (Serial::RxIrq for receive, TxIrq for transmit buffer empty)
Deprecated:
The attach function does not support cv-qualifiers. Replaced by attach(callback(obj, method), type).

Definition at line 118 of file SerialBase.h.

void attach ( T *  obj,
void(*)(T *)  method,
IrqType  type = RxIrq 
)
inherited

Attach a member function to call whenever a serial interrupt is generated.

Parameters
objpointer to the object to call the member function on
methodpointer to the member function to be called
typeWhich serial interrupt to attach the member function to (Serial::RxIrq for receive, TxIrq for transmit buffer empty)
Deprecated:
The attach function does not support cv-qualifiers. Replaced by attach(callback(obj, method), type).

Definition at line 136 of file SerialBase.h.

void baud ( int  baudrate)
inherited

Set the baud rate of the serial port.

Parameters
baudrateThe baudrate of the serial port (default = 9600).
void clear_break ( )
inherited

Clear a break condition on the serial line NOTE: Should be run at least one frame after set_break is called.

virtual int close ( )
protectedvirtualinherited

Close a file.

Returns
0 on success, negative error code on failure

Implements FileHandle.

virtual int enable_input ( bool  enabled)
virtualinherited

Enable or disable input.

Control enabling of device for input. This is primarily intended for temporary power-saving; the overall ability of the device to operate for input and/or output may be fixed at creation time, but this call can allow input to be temporarily disabled to permit power saving without losing device state.

Parameters
enabledtrue to enable input, false to disable.
Returns
0 on success
Negative error code on failure

Reimplemented in UARTSerial.

Definition at line 236 of file FileHandle.h.

virtual int enable_output ( bool  enabled)
virtualinherited

Enable or disable output.

Control enabling of device for output. This is primarily intended for temporary power-saving; the overall ability of the device to operate for input and/or output may be fixed at creation time, but this call can allow output to be temporarily disabled to permit power saving without losing device state.

Parameters
enabledtrue to enable output, false to disable.
Returns
0 on success
Negative error code on failure

Reimplemented in UARTSerial.

Definition at line 254 of file FileHandle.h.

virtual off_t flen ( )
virtualinherited

Find the length of the file.

Returns
Length of the file
Deprecated:
Replaced by `off_t FileHandle::size()'

Definition at line 195 of file FileHandle.h.

void format ( int  bits = 8,
Parity  parity = SerialBase::None,
int  stop_bits = 1 
)
inherited

Set the transmission format used by the serial port.

Parameters
bitsThe number of bits in a word (5-8; default = 8)
parityThe parity used (SerialBase::None, SerialBase::Odd, SerialBase::Even, SerialBase::Forced1, SerialBase::Forced0; default = SerialBase::None)
stop_bitsThe number of stop bits (1 or 2; default = 1)
virtual int fsync ( )
virtualinherited

Flush any buffers associated with the FileHandle, ensuring it is up to date on disk.

Returns
0 on success or un-needed, -1 on error
Deprecated:
Replaced by `int FileHandle::sync()'

Definition at line 183 of file FileHandle.h.

virtual bool is_blocking ( ) const
virtualinherited

Check current blocking or nonblocking mode for file operations.

Returns
true for blocking mode, false for nonblocking mode.

Reimplemented in UARTSerial.

Definition at line 218 of file FileHandle.h.

virtual int isatty ( )
protectedvirtualinherited

Check if the file in an interactive terminal device.

Returns
True if the file is a terminal
False if the file is not a terminal
Negative error code on failure

Reimplemented from FileHandle.

virtual void lock ( void  )
protectedvirtualinherited

Acquire exclusive access to this object.

Definition at line 80 of file Stream.h.

virtual off_t lseek ( off_t  offset,
int  whence 
)
virtualinherited

Move the file position to a given offset from a given location.

Parameters
offsetThe offset from whence to move to
whenceSEEK_SET for the start of the file, SEEK_CUR for the current file position, or SEEK_END for the end of the file.
Returns
new file position on success, -1 on failure or unsupported
Deprecated:
Replaced by `off_t FileHandle::seek(off_t offset, int whence = SEEK_SET)'

Definition at line 169 of file FileHandle.h.

virtual short poll ( short  events) const
virtualinherited

Check for poll event flags You can use or ignore the input parameter.

You can return all events or check just the events listed in events. Call is nonblocking - returns instantaneous state of events. Whenever an event occurs, the derived class should call the sigio() callback).

Parameters
eventsbitmask of poll events we're interested in - POLLIN/POLLOUT etc.
Returns
bitmask of poll events that have occurred.

Reimplemented in UARTSerial.

Definition at line 269 of file FileHandle.h.

virtual ssize_t read ( void *  buffer,
size_t  size 
)
protectedvirtualinherited

Read the contents of a file into a buffer.

Devices acting as FileHandles should follow POSIX semantics:

  • if no data is available, and nonblocking set, return -EAGAIN
  • if no data is available, and blocking set, wait until some data is available
  • If any data is available, call returns immediately
Parameters
bufferThe buffer to read in to
sizeThe number of bytes to read
Returns
The number of bytes read, 0 at end of file, negative error on failure

Implements FileHandle.

int read ( uint8_t *  buffer,
int  length,
const event_callback_t callback,
int  event = SERIAL_EVENT_RX_COMPLETE,
unsigned char  char_match = SERIAL_RESERVED_CHAR_MATCH 
)
inherited

Begin asynchronous reading using 8bit buffer.

The completion invokes registered RX event callback.

This function locks the deep sleep until any event has occurred

Parameters
bufferThe buffer where received data will be stored
lengthThe buffer length in bytes
callbackThe event callback function
eventThe logical OR of RX events
char_matchThe matching character
int read ( uint16_t *  buffer,
int  length,
const event_callback_t callback,
int  event = SERIAL_EVENT_RX_COMPLETE,
unsigned char  char_match = SERIAL_RESERVED_CHAR_MATCH 
)
inherited

Begin asynchronous reading using 16bit buffer.

The completion invokes registered RX event callback.

This function locks the deep sleep until any event has occurred

Parameters
bufferThe buffer where received data will be stored
lengthThe buffer length in bytes
callbackThe event callback function
eventThe logical OR of RX events
char_matchThe matching character
bool readable ( ) const
inherited

Definition depends on the subclass implementing FileHandle.

For example, if the FileHandle is of type Stream, readable() could return true when there is something available to read.

Returns
true when there is something available to read.

Definition at line 292 of file FileHandle.h.

virtual void rewind ( )
protectedvirtualinherited

Rewind the file position to the beginning of the file.

Note
This is equivalent to seek(0, SEEK_SET)

Reimplemented from FileHandle.

virtual off_t seek ( off_t  offset,
int  whence 
)
protectedvirtualinherited

Move the file position to a given offset from from a given location.

Parameters
offsetThe offset from whence to move to
whenceThe start of where to seek SEEK_SET to start from beginning of file, SEEK_CUR to start from current position in file, SEEK_END to start from end of file
Returns
The new offset of the file, negative error code on failure

Implements FileHandle.

void send_break ( )
inherited

Generate a break condition on the serial line.

virtual int set_blocking ( bool  blocking)
virtualinherited

Set blocking or nonblocking mode of the file operation like read/write.

Definition depends on the subclass implementing FileHandle. The default is blocking.

Parameters
blockingtrue for blocking mode, false for nonblocking mode.
Returns
0 on success
Negative error code on failure

Reimplemented in UARTSerial.

Definition at line 209 of file FileHandle.h.

void set_break ( )
inherited

Generate a break condition on the serial line NOTE: Clear break needs to run at least one frame after set_break is called.

int set_dma_usage_rx ( DMAUsage  usage)
inherited

Configure DMA usage suggestion for non-blocking RX transfers.

Parameters
usageThe usage DMA hint for peripheral
Returns
Zero if the usage was set, -1 if a transaction is on-going
int set_dma_usage_tx ( DMAUsage  usage)
inherited

Configure DMA usage suggestion for non-blocking TX transfers.

Parameters
usageThe usage DMA hint for peripheral
Returns
Zero if the usage was set, -1 if a transaction is on-going
void set_flow_control ( Flow  type,
PinName  flow1 = NC,
PinName  flow2 = NC 
)
inherited

Set the flow control type on the serial port.

Parameters
typethe flow control type (Disabled, RTS, CTS, RTSCTS)
flow1the first flow control pin (RTS for RTS or RTSCTS, CTS for CTS)
flow2the second flow control pin (CTS for RTSCTS)
virtual void sigio ( Callback< void()>  func)
virtualinherited

Register a callback on state change of the file.

The specified callback will be called on state changes such as when the file can be written to or read from.

The callback may be called in an interrupt context and should not perform expensive operations.

Note! This is not intended as an attach-like asynchronous API, but rather as a building block for constructing such functionality.

The exact timing of when the registered function is called is not guaranteed and is susceptible to change. It should be used as a cue to make read/write/poll calls to find the current state.

Parameters
funcFunction to call on state change

Reimplemented in UARTSerial.

Definition at line 314 of file FileHandle.h.

virtual off_t size ( )
protectedvirtualinherited

Get the size of the file.

Returns
Size of the file in bytes

Reimplemented from FileHandle.

virtual int sync ( )
protectedvirtualinherited

Flush any buffers associated with the file.

Returns
0 on success, negative error code on failure

Reimplemented from FileHandle.

virtual off_t tell ( )
protectedvirtualinherited

Get the file position of the file.

Note
This is equivalent to seek(0, SEEK_CUR)
Returns
The current offset in the file, negative error code on failure

Reimplemented from FileHandle.

virtual int truncate ( off_t  length)
virtualinherited

Truncate or extend a file.

The file's length is set to the specified value. The seek pointer is not changed. If the file is extended, the extended area appears as if it were zero-filled.

Parameters
lengthThe requested new length for the file
Returns
Zero on success, negative error code on failure

Reimplemented in File, and TestFile< FILE_SIZE >.

Definition at line 151 of file FileHandle.h.

virtual void unlock ( void  )
protectedvirtualinherited

Release exclusive access to this object.

Definition at line 87 of file Stream.h.

bool writable ( ) const
inherited

Definition depends on the subclass implementing FileHandle.

For example, if the FileHandle is of type Stream, writable() could return true when there is ample buffer space available for write() calls.

Returns
true if the FileHandle is writable.

Definition at line 281 of file FileHandle.h.

virtual ssize_t write ( const void *  buffer,
size_t  size 
)
protectedvirtualinherited

Write the contents of a buffer to a file.

Devices acting as FileHandles should follow POSIX semantics:

  • if blocking, block until all data is written
  • if no data can be written, and nonblocking set, return -EAGAIN
  • if some data can be written, and nonblocking set, write partial

    Parameters
    bufferThe buffer to write from
    sizeThe number of bytes to write
    Returns
    The number of bytes written, negative error on failure

Implements FileHandle.

int write ( const uint8_t *  buffer,
int  length,
const event_callback_t callback,
int  event = SERIAL_EVENT_TX_COMPLETE 
)
inherited

Begin asynchronous write using 8bit buffer.

The completion invokes registered TX event callback

This function locks the deep sleep until any event has occurred

Parameters
bufferThe buffer where received data will be stored
lengthThe buffer length in bytes
callbackThe event callback function
eventThe logical OR of TX events
int write ( const uint16_t *  buffer,
int  length,
const event_callback_t callback,
int  event = SERIAL_EVENT_TX_COMPLETE 
)
inherited

Begin asynchronous write using 16bit buffer.

The completion invokes registered TX event callback

This function locks the deep sleep until any event has occurred

Parameters
bufferThe buffer where received data will be stored
lengthThe buffer length in bytes
callbackThe event callback function
eventThe logical OR of TX events
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