ESP32 Hardware Serial

[Puddleraker]

I would like some assistance in modifying some basic code for an MP3 Dfplayer to utilise the hardware serial pins (16/17) on an ESP32. Any assistance would be very appreciated.

Many thanks. Neil

#include <DFPlayerMini_Fast.h>

#if !defined(UBRR1H)

#include <SoftwareSerial.h>

SoftwareSerial mySerial(10, 11); // RX, TX

#endif

DFPlayerMini_Fast myMP3;

void setup()

{

Serial.begin(115200);

#if !defined(UBRR1H)

mySerial.begin(9600);

myMP3.begin(mySerial, true);

#else

Serial1.begin(9600);

myMP3.begin(Serial1, true);

#endif

Serial.println("Setting volume to max");

myMP3.volume(30);

Serial.println("Looping track 1");

myMP3.loop(1);

}

void loop()

{

[Alan Childs]

What ESP32 are you using?

You probably want to change 
#include <SoftwareSerial.h> SoftwareSerial mySerial(10, 11); to

#include <HardwareSerial.h> HardwareSerial mySerial(16, 17); // Or maybe 17, 16

HardwareSerial is a core header so you shouldn't need to install any new libraries for it.
https://github.com/arduino/ArduinoCore-avr/blob/master/cores/arduino/HardwareSerial.h

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[Puddleraker]

Hi Alan, many thanks for your quick reply. Im using an ESP32 WROOM.

Would your suggested chnchangeage be the only line I have to amend?

Thanks. Neil

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[Alan Childs]

I'm not sure if

#if !defined(UBRR1H)
is defined or not. The hash # before the if indicates that the code between that line and the #endif will only be copied to the ESP32 if UBRR1H is not configured in the code somewhere. The ESP32 itself won't use that IF statement.

In your code you appear to have different references to serial - mySerial ... Serial ... Serial1 .... You can probably tidy the code to only reference one name, unless you are really using multiple serials.

It's possible that your program is using more than one serial interface, but only one can be hardware, so that is why there is a software serial. At a guess the program is using hardware serial to drive an MP3 module and software serial to output debug code.
Debug code doesn't need to be fast or partially efficient, but the MP3 module does.

[Puddleraker]

Thanks. I will give it a go later and see what happens. 

The code is the example code from Github.

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[Alan Childs]

#if !defined(UBRR1H)
That's probably a check to see if the serial is already setup as hardware for this build, and if not then set it up as software. So, if you have a ESP32 that supports more that one Hardware UART, then it has already configured  mySerial as hardware somewhere else?

[Alan Childs]

Actually yes, if defined(UBRR1H) which on a ESP32-WROOM it is then you have Serial1 as a default hardware interface, so the compiler uses myMP3.begin(Serial1, true); 

So you already are using hardware serial.

[Puddleraker]

Ok, thank you.

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