Serial Communications (Serial Class)

Basic Library

Digital I/O
Analog I/O
Advanced I/O
Time
Math
Trigonometry
Random Numbers
Bits and Bytes
Interrupts
Serial Comm.

Standard Library

Servo Motor
Character LCD
SPI
I²C (Wire)
SD Card
SD (File Operations)
Periodic Operation
Clock (RTC)

Serial Communications

This library allows communication between the GR-CITRUS board and PCs or other microcontroller (MCU) devices. With a total of 8 serial channels available, 1 channel is for USB communication and 4 channels are for UART communication. The following describe channels corresponding to pins, you can confirm these using the pin map.

Serial: USB communication
Serial1: 1(RX), 0(TX)
Serial2: 6(RX), 5(TX)
Serial3: 8(RX), 7(TX)
Serial4: 11(RX), 12(TX)

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.

begin

Description: Sets the data rate in bits per second (baud) for serial data transmission. An optional second argument configures the data, parity and stop bits.
Syntax: Serial.begin(unsigned long speed, config)
Parameters: speed: In bits per second (baud approx. 1,200 to 3,000,000Hz)
config (optional): Sets data, parity and stop bits. Valid values are:
   SERIAL_5N1, SERIAL_6N1, SERIAL_7N1, SERIAL_8N1 (default)
   SERIAL_5N2, SERIAL_6N2, SERIAL_7N2, SERIAL_8N2
   SERIAL_5E1, SERIAL_6E1, SERIAL_7E1, SERIAL_8E1
   SERIAL_5E2, SERIAL_6E2, SERIAL_7E2, SERIAL_8E2
   SERIAL_5O1, SERIAL_6O1, SERIAL_7O1, SERIAL_8O1
   SERIAL_5O2, SERIAL_6O2, SERIAL_7O2, SERIAL_8O2
Returns: None
Notes: Its margin of error depends on setting baud rate.
About general baud rates, 4800, 9600, 19200, 38400, 57600, 115200, 230400 (bps), the serial communication may not occur (error) within a byte.
But in the case of setting a baud rate larger than what is listed above, it is better to set the following baud rate, 500000, 1000000, 1500000, 3000000 (bps).

end

Description: Disables the serial communication port.
Syntax: Serial.end()
Parameters: None
Returns: None

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

print

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

Sample Program

Sample to print each format.


#include <Arduino.h>
/*
Uses a FOR loop for data and prints a number in various formats.
*/
int x = 0;    // variable
 
void setup() {
  Serial.begin(9600);      // open the serial port at 9600 bps:
}
 
void loop() {  
  // print labels 
  Serial.print("RAW");       // prints a label
  Serial.print("\t");              // prints a tab
 
  Serial.print("DEC");  
  Serial.print("\t");      
 
  Serial.print("HEX"); 
  Serial.print("\t");   
 
  Serial.print("OCT");
  Serial.print("\t");
 
  Serial.print("BIN");
  Serial.print("\t"); 
 
  for(x=0; x< 64; x++){    // only part of the ASCII chart, change to suit
 
    // print it out in many formats:
    Serial.print(x);       // print as an ASCII-encoded decimal - same as "DEC"
    Serial.print("\t");    // prints a tab
 
    Serial.print(x, DEC);  // print as an ASCII-encoded decimal
    Serial.print("\t");    // prints a tab
 
    Serial.print(x, HEX);  // print as an ASCII-encoded hexadecimal
    Serial.print("\t");    // prints a tab
 
    Serial.print(x, OCT);  // print as an ASCII-encoded octal
    Serial.print("\t");    // prints a tab
 
    Serial.println(x, BIN);  // print as an ASCII-encoded binary
    //                             then adds the carriage return with "println"
    delay(200);            // delay 200 milliseconds
  }
  Serial.println("");      // prints another carriage return
}

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