DFPlayer Mini unable to begin

Question

I'm using a ESP32-Wroom-32d Firebeetle V4 board and the DFplayer Mini but I'm unable to get a signal from the DFPlayer to the ESP.

I checked every connection with a multimeter and see that the player gets 5V and read the incoming signal from the ESP. When I unplug the power and re-plug it to the DFPlayer, I get a signal from the RX pin but that's the only time I get a signal.

I'm using the test program from the site but nothing seems to work. I always get the "unable to begin" error. The SD card is inserted and the files are stored correctly. The SD card is also 128 MB so that's also not the issue. If I connect my speaker it also doesn't help. I don't know what to check anymore or if my DFPlayer is fried.

I connected the IO3 pin which is the RX pin to the TX pin of the DFPlayer and the TX pin which is IO1 from the ESP to the RX pin of the DFPlayer. I also have a small 2 watt speaker connected to the SPK1 and the SPK2 pin of the DFPlayer. I also tested it without the speaker and still get the same error message and no response from the DFPlayer.

/***************************************************
DFPlayer - A Mini MP3 Player For Arduino
 <https://www.dfrobot.com/index.php?route=product/product&product_id=1121>

 ***************************************************
 This example shows the basic function of library for DFPlayer.

 Created 2016-12-07
 By [Angelo qiao]([email protected])

 GNU Lesser General Public License.
 See <http://www.gnu.org/licenses/> for details.
 All above must be included in any redistribution
 ****************************************************/

/***********Notice and Trouble shooting***************
 1.Connection and Diagram can be found here
 <https://www.dfrobot.com/wiki/index.php/DFPlayer_Mini_SKU:DFR0299#Connection_Diagram>
 2.This code is tested on Arduino Uno, Leonardo, Mega boards.
 ****************************************************/

#include "Arduino.h"
#include "DFRobotDFPlayerMini.h"

DFRobotDFPlayerMini myDFPlayer;
void printDetail(uint8_t type, int value);

void setup()
{
  Serial.begin(9600);

  Serial.println();
  Serial.println(F("DFRobot DFPlayer Mini Demo"));
  Serial.println(F("Initializing DFPlayer ... (May take 3~5 seconds)"));

  if (!myDFPlayer.begin(Serial)) {  //Use softwareSerial to communicate with mp3.
    Serial.println(F("Unable to begin:"));
    Serial.println(F("1.Please recheck the connection!"));
    Serial.println(F("2.Please insert the SD card!"));
    while(true);
  }
  Serial.println(F("DFPlayer Mini online."));

  myDFPlayer.volume(10);  //Set volume value. From 0 to 30
  myDFPlayer.play(1);  //Play the first mp3
}

void loop()
{
  static unsigned long timer = millis();

  if (millis() - timer > 3000) {
    timer = millis();
    myDFPlayer.next();  //Play next mp3 every 3 second.
  }

  if (myDFPlayer.available()) {
    printDetail(myDFPlayer.readType(), myDFPlayer.read()); //Print the detail message from DFPlayer to handle different errors and states.
  }
}

void printDetail(uint8_t type, int value){
  switch (type) {
    case TimeOut:
      Serial.println(F("Time Out!"));
      break;
    case WrongStack:
      Serial.println(F("Stack Wrong!"));
      break;
    case DFPlayerCardInserted:
      Serial.println(F("Card Inserted!"));
      break;
    case DFPlayerCardRemoved:
      Serial.println(F("Card Removed!"));
      break;
    case DFPlayerCardOnline:
      Serial.println(F("Card Online!"));
      break;
    case DFPlayerPlayFinished:
      Serial.print(F("Number:"));
      Serial.print(value);
      Serial.println(F(" Play Finished!"));
      break;
    case DFPlayerError:
      Serial.print(F("DFPlayerError:"));
      switch (value) {
        case Busy:
          Serial.println(F("Card not found"));
          break;
        case Sleeping:
          Serial.println(F("Sleeping"));
          break;
        case SerialWrongStack:
          Serial.println(F("Get Wrong Stack"));
          break;
        case CheckSumNotMatch:
          Serial.println(F("Check Sum Not Match"));
          break;
        case FileIndexOut:
          Serial.println(F("File Index Out of Bound"));
          break;
        case FileMismatch:
          Serial.println(F("Cannot Find File"));
          break;
        case Advertise:
          Serial.println(F("In Advertise"));
          break;
        default:
          break;
      }
      break;
    default:
      break;
  }
}