Receive Only Software Serial (Now with files)

Hello! I have started projects where I do not need to transmit serial data however the serial library still forces me to declare both a TX and RX pin. I modified the Software Serial library to only receive data and was able to save about 500 bytes (and a pin!) on my ATtiny85. The modifications were inspired by Nick Gammon’s SendOnlySoftwareSerial (which works great!)

Unfortunately, I am not a lawyer and I am unsure of the proper etiquette on how to mark my changes if I were to “publish” the modified libraries. If I could get some guidance, I would love to contribute this library (it is still being tested though!).

I have tested the library and it seems to work. Just make a folder called ReceiveOnlySoftwareSerial and place the three attached folders into it. Then place that folder into your arduino/sketchbook/ibrary folder to “install”. It works exactly the same as SoftwareSerial except you only need to specify one receiver pin during initialization. This is also my first modified library, any pointers/tips would be GREATLY appreciated!

ReceiveOnlySoftwareSerial.cpp (11.9 KB)

ReceiveOnlySoftwareSerial.h (3.42 KB)

keywords.txt (609 Bytes)

Just follow Nick's example. Not being a lawyer is, IMO, a good thing!

SendOnlySoftwareSerial - adapted from SoftwareSerial by Nick Gammon 28th June 2012

SoftwareSerial.h (formerly NewSoftSerial.h) - Multi-instance software serial library for Arduino/Wiring -- Interrupt-driven receive and other improvements by ladyada   ( -- Tuning, circular buffer, derivation from class Print/Stream,   multi-instance support, porting to 8MHz processors,   various optimizations, PROGMEM delay tables, inverse logic and   direct port writing by Mikal Hart ( -- Pin change interrupt macros by Paul Stoffregen ( -- 20MHz processor support by Garrett Mace ( -- ATmega1280/2560 support by Brett Hagman (

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


ifndef SendOnlySoftwareSerial_h

define SendOnlySoftwareSerial_h