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SerialBuffered Class Reference
Public Member Functions | Protected Member Functions

SerialBuffered Class Reference

SerialBuffered based on Serial but fully buffered IO. More...

#include <SerialBuffered.h>

Public Member Functions

 SerialBuffered (PinName tx, PinName rx)
 Create a SerialBuffered object connected to the specified pins.
char getc (void)
 Get a character from the serial stream.
int getc (bool blocking)
 Gets a character from the serial stream with optional blocking.
int putc (int c)
 Puts a characher to the serial stream.
int putc (int c, bool blocking)
 Puts a characher to the serial stream.
int readable (void)
 Are there characters in the RX buffer we can read?
int writeable (void)
 Is there room in the TX buffer to send a character?
void baud (int baudrate)
 Set's the UART baud rate.
void format (int bits, int parity, int stopbits)
 Sets the serial format.
void set_tx_buffer_size (int buffer_size)
 Change the TX buffer size.
void set_tx_buffer_size (int buffer_size, char *buffer)
 Change the TX buffer size and provide your own allocation.
void set_rx_buffer_size (int buffer_size)
 Change the RX buffer size.
void set_rx_buffer_size (int buffer_size, char *buffer)
 Change the RX buffer size and provide your own allocation.

Protected Member Functions

uint16_t calculate_baud (int baud, int uart)
 Calculate the divisors for a UART's baud.

Detailed Description

SerialBuffered based on Serial but fully buffered IO.

Example: 

 #include "mbed.h"
 #include "SerialBuffered.h"

 SerialBuffered serial1 (p13, p14); 
 SerialBuffered serial2 (p28, p27);

 int main() {
     while(1) {
         if (serial1.readable()) {
             while (!serial2.writeable());
             serial2.putc(serial1.getch());
         }
         if (serial2.readable()) {
             while (!serial1.writeable());
             serial1.putc(serial2.getc());
         }
     }
 }

Note, because this system "traps" the interrupts for the UART being used do not use the .attach() method, otherwise the buffers will cease functioning. Or worse, behaviour becomes unpredictable.

Definition at line 59 of file SerialBuffered.h.

Constructor & Destructor Documentation

SerialBuffered ( PinName  tx,
PinName  rx 
)

Create a SerialBuffered object connected to the specified pins.

Parameters:
PinNametx The Mbed TX pin for the uart port.
PinNamerx The Mbed RX pin for the uart port.

Definition at line 38 of file SerialBuffered.cpp.

Member Function Documentation

void baud ( int  baudrate )

Set's the UART baud rate.

Any allowed baudrate may be passed. However, you should ensure it matches the far end of the serial link.

Parameters:
intThe baudrate to set.

Definition at line 30 of file sb_aux.cpp.

uint16_t calculate_baud ( int  baud,
int  uart 
) [protected]

Calculate the divisors for a UART's baud.

Parameters:
intThe desired baud rate
intThe UART in use to calculate for

Definition at line 38 of file sb_aux.cpp.

void format ( int  bits,
int  parity,
int  stopbits 
)

Sets the serial format.

Valid serial bit lengths are:-

  • SerialBuffered::WordLength5
  • SerialBuffered::WordLength6
  • SerialBuffered::WordLength7
  • SerialBuffered::WordLength8

Valid serial parity are:-

  • SerialBuffered::NoParity
  • SerialBuffered::OddParity
  • SerialBuffered::EvenParity
  • SerialBuffered::Forced1
  • SerialBuffered::Forced0

Valid stop bits are:-

  • SerialBuffered::None
  • SerialBuffered::One
  • SerialBuffered::Two
Parameters:
intbits
intparity
intstopbits

Definition at line 26 of file sb_aux.cpp.

int getc ( bool  blocking )

Gets a character from the serial stream with optional blocking.

This method allows for getting a character from the serial stream if one is available. If blocking is true, the method will wait for serial input if the RX buffer is empty. If blocking is false, the method will return immediately if the RX buffer is empty. On return, if not blocking and the buffer was empty, -1 is returned.

Parameters:
blockingtrue or false, when true will block.
Returns:
int An int representation of the 8bit char or -1 on buffer empty.

Definition at line 26 of file sb_getc.cpp.

char getc ( void   )

Get a character from the serial stream.

Returns:
char A char value of the character read.

Definition at line 40 of file sb_getc.cpp.

int putc ( int  c,
bool  blocking 
)

Puts a characher to the serial stream.

As with putc(int c) this function allows for a character to be sent to the uart TX port. However, an extra parameter is added to allow the caller to decide if the method should block or not. If blocking is disabled then this method returns -1 to signal there was no room in the TX FIFO or the TX buffer. The character c passed is has not therefore been sent.

Parameters:
intAn int representation of the 8bit character to send.
booltrue if blocking required, false to disable blocking.
Returns:
int Zero on success, -1 if no room in TX FIFO or TX buffer.

Definition at line 26 of file sb_putc.cpp.

int putc ( int  c )

Puts a characher to the serial stream.

putc

This sends a character out of the uart port or, if no room in the TX FIFO, will place the character into the TX buffer. Note, if the TX buffer is also full, this method will block (wait) until there is room in the buffer.

Parameters:
intAn int representation of the 8bit character to send.
Returns:
int Always returns zero.

Definition at line 50 of file sb_putc.cpp.

int readable ( void   )

Are there characters in the RX buffer we can read?

Returns:
int 1 if characters are available, 0 otherwise.

Definition at line 44 of file sb_getc.cpp.

void set_rx_buffer_size ( int  buffer_size )

Change the RX buffer size.

By default, when the SerialBuffer object is created, a default RX buffer of 256 bytes in size is created. If you need a bigger (or smaller) buffer then use this function to change the RX buffer size.

Note, when a buffer is resized, any previous buffer in operation is discarded (destroyed and lost).

Parameters:
intThe size of the RX buffer required.

Definition at line 100 of file sb_aux.cpp.

void set_rx_buffer_size ( int  buffer_size,
char *  buffer 
)

Change the RX buffer size and provide your own allocation.

This methos allows for the buffer size to be changed and for the caller to pass a pointer to an area of RAM they have already set aside to hold the buffer. The standard method is to malloc space from the heap. This method allows that to be overriden and use a user supplied buffer.

Note, the buffer you create must be of the size you specify! Note, when a buffer is resized, any previous buffer in operation is discarded (destroyed and lost).

Parameters:
intThe size of the RX buffer required.
char*A pointer to a buffer area you previously allocated.

Definition at line 79 of file sb_aux.cpp.

void set_tx_buffer_size ( int  buffer_size,
char *  buffer 
)

Change the TX buffer size and provide your own allocation.

This methos allows for the buffer size to be changed and for the caller to pass a pointer to an area of RAM they have already set aside to hold the buffer. The standard method is to malloc space from the heap. This method allows that to be overriden and use a user supplied buffer.

Note, the buffer you create must be of the size you specify! Note, when a buffer is resized, any previous buffer in operation is discarded (destroyed and lost).

Parameters:
intThe size of the TX buffer required.
char*A pointer to a buffer area you previously allocated.

Definition at line 52 of file sb_aux.cpp.

void set_tx_buffer_size ( int  buffer_size )

Change the TX buffer size.

By default, when the SerialBuffer object is created, a default TX buffer of 256 bytes in size is created. If you need a bigger (or smaller) buffer then use this function to change the TX buffer size.

Note, when a buffer is resized, any previous buffer in operation is discarded (destroyed and lost).

Parameters:
intThe size of the TX buffer required.

Definition at line 73 of file sb_aux.cpp.

int writeable ( void   )

Is there room in the TX buffer to send a character?

Returns:
int 1 if room available, 0 otherwise.

Definition at line 54 of file sb_putc.cpp.

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