A serial port (UART) for communication with other devices using Half-Duplex, allowing transmit and receive on a single shared transmit and receive line. More...

#include <SerialHalfDuplex.h>

Inherits mbed::Serial.

Public Member Functions
	SerialHalfDuplex (PinName tx, PinName rx)
	Create a half-duplex serial port, connected to the specified transmit and receive pins.
void	baud (int baudrate)
	Set the baud rate of the serial port.
void	format (int bits=8, Parity parity=SerialBase::None, int stop_bits=1)
	Set the transmission format used by the serial port.
int	readable ()
	Determine if there is a character available to read.
int	writeable ()
	Determine if there is space available to write a character.
void	attach (Callback< void()> func, IrqType type=RxIrq)
	Attach a function to call whenever a serial interrupt is generated.
template<typename T >
	MBED_DEPRECATED_SINCE ("mbed-os-5.1","The attach function does not support cv-qualifiers. Replaced by ""attach(callback(obj, method), type).") void attach(T *obj
	Attach a member function to call whenever a serial interrupt is generated.
void	set_flow_control (Flow type, PinName flow1=NC, PinName flow2=NC)
	Set the flow control type on the serial port.
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.
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.
void	abort_write ()
	Abort the on-going write transfer.
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.
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.
void	abort_read ()
	Abort the on-going read transfer.
int	set_dma_usage_tx (DMAUsage usage)
	Configure DMA usage suggestion for non-blocking TX transfers.
int	set_dma_usage_rx (DMAUsage usage)
	Configure DMA usage suggestion for non-blocking RX transfers.
Protected Member Functions
virtual void	lock ()
	Acquire exclusive access to this serial port.
virtual void	unlock ()
	Release exclusive access to this serial port.
virtual ssize_t	write (const void *buffer, size_t length)
	Write the contents of a buffer to the file.
virtual ssize_t	read (void *buffer, size_t length)
	Function read Reads the contents of the file into a buffer.
virtual int	close ()
	Close the file.
virtual off_t	lseek (off_t offset, int whence)
	Move the file position to a given offset from a given location.
virtual int	isatty ()
	Check if the handle is for a interactive terminal device.
virtual int	fsync ()
	Flush any buffers associated with the FileHandle, ensuring it is up to date on disk.

Detailed Description

A serial port (UART) for communication with other devices using Half-Duplex, allowing transmit and receive on a single shared transmit and receive line.

Only one end should be transmitting at a time.

Both the tx and rx pin should be defined, and wired together. This is in addition to them being wired to the other serial device to allow both read and write functions to operate.

For Simplex and Full-Duplex Serial communication, see Serial()

Example:

 // Send a byte to a second HalfDuplex device, and read the response

 #include "mbed.h"

 // p9 and p10 should be wired together to form "a"
 // p28 and p27 should be wired together to form "b"
 // p9/p10 should be wired to p28/p27 as the Half Duplex connection

 SerialHalfDuplex a(p9, p10);
 SerialHalfDuplex b(p28, p27);

 void b_rx() { // second device response
     b.putc(b.getc() + 4);
 }

 int main() {
     b.attach(&b_rx);
     for (int c = 'A'; c < 'Z'; c++) {
         a.putc(c);
         printf("sent [%c]\n", c);
         wait(0.5);   // b should respond
         if (a.readable()) {
             printf("received [%c]\n", a.getc());
         }
     }
 }

Definition at line 57 of file SerialHalfDuplex.h.

Constructor & Destructor Documentation

SerialHalfDuplex	(	PinName	tx,
		PinName	rx
	)

Create a half-duplex serial port, connected to the specified transmit and receive pins.

These pins should be wired together, as well as to the target device

Parameters:

tx	Transmit pin
rx	Receive pin

Definition at line 14 of file SerialHalfDuplex.cpp.

Member Function Documentation

void abort_read ( void ) [inherited]

Abort the on-going read transfer.

Definition at line 183 of file SerialBase.cpp.

void abort_write ( void ) [inherited]

Abort the on-going write transfer.

Definition at line 178 of file SerialBase.cpp.

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

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

Parameters:

func	A pointer to a void function, or 0 to set as none
type	Which serial interrupt to attach the member function to (Seriall::RxIrq for receive, TxIrq for transmit buffer empty)

Definition at line 70 of file SerialBase.cpp.

void baud ( int baudrate ) [inherited]

Set the baud rate of the serial port.

Parameters:

baudrate The baudrate of the serial port (default = 9600).

Definition at line 42 of file SerialBase.cpp.

int close ( ) [protected, virtual, inherited]

Close the file.

Returns:: Zero on success, -1 on error.

Implements FileHandle.

Definition at line 63 of file Stream.cpp.

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

Set the transmission format used by the serial port.

Parameters:

bits	The number of bits in a word (5-8; default = 8)
parity	The parity used (SerialBase::None, SerialBase::Odd, SerialBase::Even, SerialBase::Forced1, SerialBase::Forced0; default = SerialBase::None)
stop	The number of stop bits (1 or 2; default = 1)

Definition at line 49 of file SerialBase.cpp.

int fsync ( ) [protected, virtual, inherited]

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

Implements FileHandle.

Definition at line 105 of file Stream.cpp.

int isatty ( ) [protected, virtual, inherited]

Check if the handle is for a interactive terminal device.

If so, line buffered behaviour is used by default

Returns:: 1 if it is a terminal, 0 otherwise

Implements FileHandle.

Definition at line 101 of file Stream.cpp.

void lock ( void ) [protected, virtual, inherited]

Acquire exclusive access to this serial port.

Reimplemented from SerialBase.

Definition at line 36 of file Serial.cpp.

off_t lseek	(	off_t	offset,
		int	whence
	)		`[protected, virtual, inherited]`

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

Parameters:

offset	The offset from whence to move to
whence	SEEK_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

Implements FileHandle.

Definition at line 97 of file Stream.cpp.

MBED_DEPRECATED_SINCE	(	"mbed-os-5.1"	,
		"The attach function does not support cv-qualifiers. Replaced by ""attach(callback(obj, method), type)."
	)		`[inherited]`

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

Parameters:

obj	pointer to the object to call the member function on
method	pointer to the member function to be called
type	Which serial interrupt to attach the member function to (Seriall::RxIrq for receive, TxIrq for transmit buffer empty)

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 completition invokes registred RX event callback.

Parameters:

buffer	The buffer where received data will be stored
length	The buffer length in bytes
callback	The event callback function
event	The logical OR of RX events
char_match	The matching character

Definition at line 206 of file SerialBase.cpp.

ssize_t read	(	void *	buffer,
		size_t	length
	)		`[protected, virtual, inherited]`

Function read Reads the contents of the file into a buffer.

Parameters:

buffer	the buffer to read in to
length	the number of characters to read

Returns:: The number of characters read (zero at end of file) on success, -1 on error.

Implements FileHandle.

Definition at line 82 of file Stream.cpp.

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 completition invokes registred RX event callback.

Parameters:

buffer	The buffer where received data will be stored
length	The buffer length in bytes
callback	The event callback function
event	The logical OR of RX events
char_match	The matching character

Definition at line 216 of file SerialBase.cpp.

int readable ( ) [inherited]

Determine if there is a character available to read.

Returns:: 1 if there is a character available to read, 0 otherwise

Definition at line 55 of file SerialBase.cpp.

int set_dma_usage_rx ( DMAUsage usage ) [inherited]

Configure DMA usage suggestion for non-blocking RX transfers.

Parameters:

usage The usage DMA hint for peripheral

Returns:: Zero if the usage was set, -1 if a transaction is on-going

Definition at line 197 of file SerialBase.cpp.

int set_dma_usage_tx ( DMAUsage usage ) [inherited]

Configure DMA usage suggestion for non-blocking TX transfers.

Parameters:

usage The usage DMA hint for peripheral

Returns:: Zero if the usage was set, -1 if a transaction is on-going

Definition at line 188 of file SerialBase.cpp.

void set_flow_control	(	Flow	type,
		PinName	flow1 = `NC`,
		PinName	flow2 = `NC`
	)		`[inherited]`

Set the flow control type on the serial port.

Parameters:

type	the flow control type (Disabled, RTS, CTS, RTSCTS)
flow1	the first flow control pin (RTS for RTS or RTSCTS, CTS for CTS)
flow2	the second flow control pin (CTS for RTSCTS)

Definition at line 126 of file SerialBase.cpp.

void unlock ( void ) [protected, virtual, inherited]

Release exclusive access to this serial port.

Reimplemented from SerialBase.

Definition at line 40 of file Serial.cpp.

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 completition invokes registered TX event callback

Parameters:

buffer	The buffer where received data will be stored
length	The buffer length in bytes
callback	The event callback function
event	The logical OR of TX events

Definition at line 152 of file SerialBase.cpp.

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 completition invokes registered TX event callback

Parameters:

buffer	The buffer where received data will be stored
length	The buffer length in bytes
callback	The event callback function
event	The logical OR of TX events

Definition at line 161 of file SerialBase.cpp.

ssize_t write	(	const void *	buffer,
		size_t	length
	)		`[protected, virtual, inherited]`

Write the contents of a buffer to the file.

Parameters:

buffer	the buffer to write from
length	the number of characters to write

Returns:: The number of characters written (possibly 0) on success, -1 on error.

Implements FileHandle.

Definition at line 67 of file Stream.cpp.

int writeable ( ) [inherited]

Determine if there is space available to write a character.

Returns:: 1 if there is space to write a character, 0 otherwise

Definition at line 63 of file SerialBase.cpp.

Type:	Program
Created:	22 Oct 2016
Imports:	2
Forks:	0
Commits:	10
Dependents:	0
Dependencies:	3
Followers:	1

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