SoftwareSerial - restrictions on Pins ? (Nano)

Projects General Guidance
1

I had a functioning setup with an Arduino Nano with

SoftwareSerial mySerial = SoftwareSerial(A2, A3); 
SoftwareSerial midiSerial = SoftwareSerial(A0, A1); // RX, TX

I had to change the pin usage and switched to

SoftwareSerial mySerial = SoftwareSerial(A4, A5); 
SoftwareSerial midiSerial = SoftwareSerial(A6, A7); // RX, TX

mySerial.begin(9600);
midiSerial.begin(31250);

mySerial (Pins A4,A5) seems to work.
mySerial(Pins A6,A7) doesn't seem to work.

Are there any restrictions on pin usage on an Arduino Nano? Do I need to do any pinMode() before using the SoftSerial port?

2

No wonder, A6 and A7 are analog in only.

Why on earth would someone use software serial to disable I2C?

3

Installation and Troubleshooting is for Problems with the Arduino IDE itself NOT your project. It says so in the description of the section. Therefore I have moved your post here.

You might want to look at this How to get the best from this from this Forum before you proceed any further.

What sort of Nano? There are many different types.

4

How do I find out? It's an older Nano (old Bootloader) but I believe it's 3.0.

@Whandall : Thanks, good to know.

5

Using 2 SoftwareSerial ports on one Nano can be tricky. If you need multiple serial ports it is better to use a board that supports more serial ports. Like a Mega with 3 extra hardware serial ports.

6

Well looking at where you bought it from should help. If it is a cheap Chinese rip off it would be a Nano Classic.

But there is the Nano Every, Nano BLE 33, Nano BLE 33 sense, Nano iot, to just name the ones that come to mind.

7

Then I would say, it's a Nano clasic. Was cheapo.

8

Should work for a clone.

9

The solution used to work. I have one loop like

mySerial.listen();
  if(mySerial.isListening())
    if(mySerial.available() > 0) {
       c=mySerial.read();
       if ( c == 'b'){
       
        midiSerial.write(0x80);
        midiSerial.write(lastnote);
        midiSerial.write((unsigned char)0);
       }           
    }
10

See this for the different types of Nano

11

But what you said about A6/A7 still holds. Cannot use it for SoftwareSerial I/O, right?

12

No digital input and output on analog input only pins,
no pin change interrupt.

No software serial on those two pins.

13

The confusing thing is that the maker page Mike pointed to continues the fantasy that A6 and A7 are Analog or Digital in some places, while at the same time in one location at least both says they're analog only, at the same time listing them as Analog and Digital.

Can we really blame newbies for being confused, when two years after publication by such an organization, 15 years after the 'Nano debuted, no correction has been made? I had to ask the "Arduino Team" to correct the diagram that was on their website, back in '21, and to their credit they did so.