HardwareSerial::HardwareSerial()

Abstract

The HardwareSerial() is a constractor to create an object to perfome serial communication. In Arduino Uno, an object named ‘Serial’ is generated.

The HardwareSerial class is derived from Stream class. The Stream class is for string based stream. It defines virtual functions like available(), read(), peak() and flush(), they need to be implemented in the derived classes, and find(), findUntil(), parseInt() and so on.

The Stream class is derived from Print class. Print class implements displaying character or strings. The write() function to display a character shuould be implemented in the derived classes, in this case, HardwareSerial class. Then we can use print() and/or println().

The constractor of HardwareSerial initializes member variables.

Source Code

HardwareSerial() is defined in hardware/arduino/avr/cores/arduino/HardwareSerial_private.h as below.

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HardwareSerial::HardwareSerial(
  volatile uint8_t *ubrrh, volatile uint8_t *ubrrl,
  volatile uint8_t *ucsra, volatile uint8_t *ucsrb,
  volatile uint8_t *ucsrc, volatile uint8_t *udr) :
    _ubrrh(ubrrh), _ubrrl(ubrrl),
    _ucsra(ucsra), _ucsrb(ucsrb), _ucsrc(ucsrc),
    _udr(udr),
    _rx_buffer_head(0), _rx_buffer_tail(0),
    _tx_buffer_head(0), _tx_buffer_tail(0)
{
}

It initializes member variables using argments.

Version

Arduino AVR Boards 1.8.6

License

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/*
  Copyright (c) 2019 garretlab.
  Added source code explanation by garretlab.
*/

/*
  HardwareSerial_private.h - Hardware serial library for Wiring
  Copyright (c) 2006 Nicholas Zambetti.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

  Modified 23 November 2006 by David A. Mellis
  Modified 28 September 2010 by Mark Sproul
  Modified 14 August 2012 by Alarus
*/

Last Update

July 31, 2025