Serial1 or Serial2 in external library reference

[hicotton02]

This very well could be from lack of programming skills, but I am having an issue. In another Arduino Library, there is reference to Serial2

#define mySerial Serial2

but in the esp32 code, there is no reference to such serial. if, in my sketch, I declare

HardwareSerial Serial2(2);

I get this error:

error: 'Serial2' was not declared in this scope (from their h and cpp files)

if I try to manually declare it in their library, I either get the same error, or "redefinition of Serial2". They have this:

#include "Arduino.h"

should I change that to something else? Basically my question is "How do deal with external libraries that reference another serial port (either hardware or software) other than "Serial"?

[jestebanes]

I can't see your code but Serial2 works for me

in the cpp class add as a global variable

#include "HardwareSerial.h"
HardwareSerial Serial2(2);

and then you can use as a serial port in Arduino way, for instance

void Myclass::setSerial(int speed){
Serial2.begin(speed, SERIAL_8N1);
]

[hicotton02]

Here is the library in question:

https://github.com/itead/ITEADLIB_Arduino_Nextion

in the NexConfig.h, there is this:

#define nexSerial Serial2

in that config file, it references "NexHardware.h" and in NexHardware.cpp I added the bits above:

`#include "NexHardware.h"
#include "HardwareSerial.h"
HardwareSerial Serial2(2);

#define NEX_RET_CMD_FINISHED (0x01)
#define NEX_RET_EVENT_LAUNCHED (0x88)`

and in my sketch, I have within setup():

void setup() { Serial.begin(115200); Serial2.begin(115200); //Serial.flush(); //Serial2.flush(); }

the IDE fails with:
Main:5: error: 'Serial2' was not declared in this scope

[me-no-dev]

Here is what you can do: add to HardwareSerial.h the following line:

extern HardwareSerial Serial1;
extern HardwareSerial Serial2;

Then keep HardwareSerial Serial2(2); in your sketch.
No need to #include "HardwareSerial.h" in your sketch also.

[hicotton02]

ok that worked!

i tried adding extern HardwareSerial Serial2; to HardwareSerial.h and it didnt work. i did not know I needed to also add it in my sketch, I thought it was one or the other. Thank you so much!

[me-no-dev]

The one in HardwareSerial.h only declares that somewhere Serial2 will be implemented and with adding it to your sketch, you actually implement/instantiate the class.

[hicotton02]

Gotcha!

I appreciate all the effort you guys are putting in on this.

[tablatronix]

This throws an error for me

[tablatronix]

ohh you have to add serial1 support?

[tablatronix]

nm, #47

HardwareSerial Serial1(2);

[JacoFourie]

I am using all 3 UARTS at the same time.

#include <HardwareSerial.h>

HardwareSerial MySerial(1);
HardwareSerial ModbusSerial(2);


//In the set-up function
Serial.begin(115200);
MySerial.begin(115200, SERIAL_8N1, 16, 17);
ModbusSerial.begin(9600 ,SERIAL_8E1, 4, 15);

//Then print to each UART as you like.
Serial.println("Hallo World");
MySerial.flush();
MySerial.println("Hello World");
ModbusSerial.flush();
ModbusSerial.println("Hello World");

[maxim25111]

I have solution for stm32F1 communicating with nextion display. This is extremely difficult to find that solution. But it is extrimly easy to set.
I was trying many configurations from 2 days. Until I opened this file and try change Serial to Serial2
Find in folder NexConfig.h and open it.

/** 
 * Define DEBUG_SERIAL_ENABLE to enable debug serial. 
 * Comment it to disable debug serial. 
 */
//#define DEBUG_SERIAL_ENABLE //    <-- coment that

/**
 * Define dbSerial for the output of debug messages. 
 */
//#define dbSerial Serial      // <--- Coment that.

/**
 * Define nexSerial for communicate with Nextion touch panel. 
 */
#define nexSerial Serial2 // <--- Set hire from Serial to Serial2 for stm32 pins are RX2 = PA3 TX2 = PA2
                          // <--- basic setings for arduino is SoftwareSerial... and redirect SoftwareSerial to digital 
// Serial (Serial1) is comunicating with PC USB and will make conflict with Nextion display.
//pins other than RX and TX.
// Arduino Uno have only one Serial port. 

#define nexSerial Serial2 // <--- Set hire from Serial to Serial2 for stm32 pins are RX2 = PA3 TX2 = PA2
// <--- basic setings for arduino is SoftwareSerial... and redirect SoftwareSerial to digital
// Serial (Serial1) is comunicating with PC USB and will make conflict with Nextion display.
//pins other than RX and TX.

On Your file set Serial.begin() and Serial2.begin().
I am proposing only short example in *.INO file in void setup(); Pins are from STM32F103.....

void setup(void) {
  dht.begin();   // <-- This is my temperature & humidity sensor
  //pinMode(rxPin, INPUT);  // <-- This line is only needed if is using Arduino Uno SoftwareSerial
  //pinMode(txPin, OUTPUT);   // <-- This line is only needed if is using Arduino Uno  SoftwareSerial
  Serial2.begin(9600); // For stm32 pin PA3-RX2 PA2-TX2 In nexConfig.h "#define nexSerial Serial2"
  Serial.begin(9600); // For PC Serial conection = TX1 RX1 - PB6 PB7 and PA9 PA10
  //myserial.begin(9600);  // <--- If You use Arduino Uno to simulate Serial2
  // You might need to change NexConfig.h file in your ITEADLIB_Arduino_Nextion folder
  nexInit();

[SteveAmor]

I had the same error with Serial2(2) so I named it Serial3. HardwareSerial Serial3(2) in the Arduino IDE worked for me.

[jestebanes]

After the last reviews of the library, they create the Serial2 and Serial1 objects, you only need to remove the declaration of
HardwareSerial Seiral2(2)
Because it's already made
Regards