I am planning to use an Arduino (Nano ideally, or Other) to send and receive information from several software serial ports to other arduinos, over their available pins, ideally 8 ports.

I could understand an Asynchrounous Communication having one master and 8 slaves, with the master enabling communication from one port, receiving the data from that port, and then move onto the next port, into a sampling loop.

The SoftwareSerial library allows to set up the pins individually, and set the listen() port (thanks Juraj).

I read the AltSoftSerial library handle some of the limitations of the SoftwareSerial library, but I just realized the pins cannot be configured (without... cloning the full library?).

Question is:

  • Option 1: Should I stick with the SoftwareSerial library?,
  • Option 2: Should I try the AltSoftSerial library, and figure how to duplicate it (i think this is a NO)?
  • Option 3: Understand that none of these libraries are prepared for this, and seek for other alternative?
  • Option 4: It is pointless to have several serial trunks in Arduino, if only one will work at a time, and should hence try to arrange just one serial trunk?
  • 1
    you must set which instance should listen with listen(). only one can listen
    – Juraj
    Commented Feb 5, 2019 at 19:02
  • 2
    You might be better off with an rs485 multi-drop bus.
    – Majenko
    Commented Feb 5, 2019 at 19:23

2 Answers 2


I tried to use MIDI (which is quite slow: 31,250 bps), and that didn't work reliable with the software serial on the Arduino Uno. Since I wanted multiple ports, I switched to the Arduino Mega which has FOUR harware serial ports. I would suggest this above using so many software serial ports; it also will relieve your processor to use hardware serials.


You could use a part with 2 hardware serial ports (Atmega1284P), and use a simple mux chip to switch between the slaves for the master to receive from, such as DG406 https://www.digikey.com/products/en/integrated-circuits-ics/interface-analog-switches-multiplexers-demultiplexers/747?k=dg406&k=&pkeyword=dg406&sv=0&pv1989=0&pv433=170&sf=0&quantity=&ColumnSort=0&page=1&stock=1&pageSize=25

Hardware serial will allow for faster comm's too, vs software serial. 1284P is Arduino friendly too.


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