HC-05 can not use lower pins only 8 and higher #include &lt;Arduino.h&gt;
#include &lt;SoftwareSerial.h&gt;

char Incoming_value = 0;

// SoftwareSerial BTSerial( 10, 11 ); // RX | TX +
// SoftwareSerial BTSerial( 9, 10 ); // RX | TX +
// SoftwareSerial BTSerial( 8, 9 ); // RX | TX +
// SoftwareSerial BTSerial( 7, 8 ); // RX | TX - ???
// SoftwareSerial BTSerial( 6, 7 ); // RX | TX - ???
// SoftwareSerial BTSerial( 5, 6 ); // RX | TX - ???
// SoftwareSerial BTSerial( 4, 5 ); // RX | TX - ???
// SoftwareSerial BTSerial( 3, 4 ); // RX | TX - ???

SoftwareSerial BTSerial( 8, 9 ); // RX | TX +

void setup() {
        BTSerial.begin( 9600 );
        pinMode( 13, OUTPUT);
}

void loop() {
        delay( 1000 );
        BTSerial.println( "hello" );
        if( BTSerial.available() &gt; 0 ) {
                BTSerial.println( "BINGO!" );
                Incoming_value = BTSerial.read();
                BTSerial.println( Incoming_value );
                if ( Incoming_value == '1' ) digitalWrite( 13, HIGH );
                else if ( Incoming_value == '0' ) digitalWrite( 13, LOW );
        }
}


My HC-05 Bluetooth module wont't work on lowers digital pins.


  BOARD_TAG = leonardo



It works fine on highers digital pins: 8-9, 9-10 or 10-11 - everything fine.
but 2-3, 3-4, 4-5, 5-6, 6-7 or 7-8 - no....


Why? Should I inject jumper somewhere or what?

And yes: @Majenko, "0,1 - is required to debug from host". I want to have Serial from PC and BTSerial from bluetooth - to have both accesses to device simultaneously.

@Peter_Paul_Kiefer, so, you think, this is impossible with lowest pins, lower than 8?
From the official SoftwareSerial Site: https://www.arduino.cc/en/Reference/softwareSerial (Section Limitations)


  Not all pins on the Leonardo and Micro support change interrupts, so
  only the following can be used for RX: 8, 9, 10, 11, 14 (MISO), 15
  (SCK), 16 (MOSI).