isPlaying() always returns 0 when multiple instances are active

[kshoichi]

Other functions such as .volume, .play, and .stop all work fine with multiple instances. Tested and confirmed using this code:

#include "Arduino.h"
#include <SoftwareSerial.h>
#include <DFPlayerMini_Fast.h>

//audio hardware
SoftwareSerial mySerial1(A0, A1); // RX, TX
SoftwareSerial mySerial2(A2, A3); // RX, TX
SoftwareSerial mySerial3(2, 3); // RX, TX
SoftwareSerial mySerial4(4, 5); // RX, TX
DFPlayerMini_Fast DFP1;
//DFPlayerMini_Fast DFP2;
//DFPlayerMini_Fast DFP3;
//DFPlayerMini_Fast DFP4;

void setup()
{
  Serial.begin(115200); 
  Serial.println(F("Booting Up..."));
  Serial.println(F("Init mySerial 1"));
  mySerial1.begin(9600);
  //mySerial2.begin(9600);
  //mySerial3.begin(9600);
  //mySerial4.begin(9600);

  DFP1.begin(mySerial1);
  //DFP2.begin(mySerial2);
  //DFP3.begin(mySerial3);
  //DFP4.begin(mySerial4);
  DFP1.play(1); 
}

void loop()
{
  Serial.println(DFP1.isPlaying());  
}

[kshoichi]

Looks like .currentVolume() returns -1 instead of the volume when multiple instances are active. So it's probably the same for all the queries. Could be caused by the SoftwareSerial library or this repo's query function?

[kshoichi]

Making SoftwareSerial listen before querying the DFPlayer seems to fix this issue. In this case adding "mySerial1.listen();" prior to the .isPlaying() line makes it work. Not necessary if you are only using one instance of DFPLayerMini_Fast.