HardwareSerial::end()

Abstract

The HardwareSerial::end() ends the serial communication and sets RX and TX pins to normal input/output mode.

The HardwareSerial::end() sets UCSR0B register.

Source Code

The HardwareSerial::end() is defined in hardware/arduino/avr/cores/arduino/HardwareSerial.cpp as below.

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void HardwareSerial::end()
{
  // wait for transmission of outgoing data
  flush();
 
  cbi(*_ucsrb, RXEN0);
  cbi(*_ucsrb, TXEN0);
  cbi(*_ucsrb, RXCIE0);
  cbi(*_ucsrb, UDRIE0);
   
  // clear any received data
  _rx_buffer_head = _rx_buffer_tail;
}

No inputs, no outputs.

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void HardwareSerial::end()
{

Call HardwareSerial::flush() to send untransmitted data.

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// wait for transmission of outgoing data
flush();

Then sets the register.

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cbi(*_ucsrb, _rxen);
cbi(*_ucsrb, _txen);
cbi(*_ucsrb, _rxcie);  
cbi(*_ucsrb, _udrie);

Clears RXEn, TXEn, RXCIEn and UDUIEn in ucsrb(UCSR0B) using cbi().

Finally clears receive buffer.

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  // clear any received data
  _rx_buffer_head = _rx_buffer_tail;
}

version

Arduino AVR Boards 1.8.6

License

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

/*
  HardwareSerial.cpp - 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
  Modified 3 December 2013 by Matthijs Kooijman
*/

Last Update

August 25, 2019