Serial Communications (SoftwareSerial Class) | Renesas
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Serial Communications (SoftwareSerial Class)
SoftwareSerial is a library that enables serial communication with a digital pin other than the serial port. It is possible to have multiple software serial ports with speeds up to 115200bps. However, be careful when the baud rate is 115200bps because the reception latch timing is not so accurate. The receive buffer is fixed at 256 bytes.
To use it, specify #include <SoftwareSerial.h>. You will need to create an instance of SoftwareSerial class.
Constructor for SoftwareSerial
- Description
- This is a constructor for creating an instance of the SoftwareSerial class.
- Syntax
- SoftwareSerial(receivePin, transmitPin)
SoftwareSerial(receivePin, transmitPin, inverse_logic) - Parameters
- receivePin: Receive pin
transmitPin: Transmit pin
inverse_logic: Inverse logic (default false) - Returns
- None
begin
- Description
- Sets the data rate in bits per second (baud).
- Syntax
- serial.begin(int speed)
- Parameters
- speed: In bits per second (baud)
- Returns
- None
end
- Description
- Disables serial communication port.
- Syntax
- serial.end()
- Parameters
- None
- Returns
- None
available
- Description
- Gets the number of bytes (characters) available for reading from the serial port.
- Syntax
- int serial.available()
- Parameters
- None
- Returns
- The number of bytes available in the serial buffer. Returns 0 when there is no data.
read
- Description
- Reads 1 byte of data from the receive buffer in the the serial communications port.
- Syntax
- int serial.read()
- Parameters
- None
- Returns
- Data. If no data available, returns -1.
peek
- Description
- Returns the next byte (character) of incoming serial data in the serial communications port without removing it from the receive buffer. CRLF conversion is not carried out.
- Syntax
- int serial.peek()
- Parameters
- None
- Returns
- The first byte of incoming serial data available (or -1 if no data is available).
flush
- Description
- Waits until the send buffer of the serial communications port is empty.
- Syntax
- serial.flush()
- Parameters
- None
- Returns
- None
write
- Description
- Writes a character string or data to the serial communications port.
- Syntax
- serial.write(const char* str)
serial.write(const unsigned char* buf, int len) - Parameters
- str: A string to send as a series of bytes
buf: An array (pointer) to send data
len: Length of the output (written) data - Returns
- The number of bytes of output (written) data.
- Description
- Prints a character string to the serial communications port.
- Syntax
- serial.print(val)
serial.print(val, format) - Parameters
- val: The value or character string to print
format: Specifies the number base for values (BIN: binary or base 2, OCT: octal or base 8, DEC: decimal or base 10, HEX: hexadecimal or base 16) - Returns
- The number of bytes printed.
println
- Description
- Prints a character string to the serial communications port followed by a carriage return.
- Syntax
- serial.println(val)
serial.println(val, format) - Parameters
- val: The value or character string to print
format: Specifies the number base for values (BIN: binary or base 2, OCT: octal or base 8, DEC: decimal or base 10, HEX: hexadecimal or base 16) - Returns
- The number of bytes printed.
listen
- Description
- Enables the selected software serial port to listen. Only one software serial port can listen at a time; data that arrives for other ports will be discarded. Any data already received is discarded during the call to listen() (unless the given instance is already listening).
- Syntax
- bool serial.listen()
- Parameters
- None
- Returns
- True or False
isListening
- Description
- Tests to see if requested software serial port is actively listening.
- Syntax
- bool serial.isListening()
- Parameters
- None
- Returns
- True or False
overflow
- Description
- Tests to see if a software serial buffer overflow has occurred. Calling this function clears the overflow flag, meaning that subsequent calls will return false unless another byte of data has been received and discarded in the meantime.
- Syntax
- bool serial.overflow()
- Parameters
- None
- Returns
- True or False
Example
This is an example that specifies Pin 10 as receive and Pin 11 as transmit and outputs the value of A0.
#include <Arduino.h>
#include <SoftwareSerial.h>
SoftwareSerial serial(10, 11); // RX: 10, TX:11
int analogValue;
void setup()
{
serial.begin(9600);
}
void loop()
{
analogValue = analogRead(A0);
delay(100);
}
