ESP32XX serial monitor

[davejel]

Board

ESP32XX

Device Description

Hi all
I'm not even sure if this is the right place to report my issue
I am using ESP32Dev module and ESP32S3Dev module with Arduino 2.3.6
when debugging I have always used serial monitor which has always served well
recently, for no apparent reason the serial monitor on my boards (i have several nodes) stopped working and I have been ppulling my hair out trying to find a solution then i came across this issue at https://esp32.com/viewtopic.php?t=31910
some of the users here advocate editing boards.txt and changing
CoreESP32.serial.disableDTR=false
CoreESP32.serial.disableRTS=false
to
CoreESP32.serial.disableDTR=true
CoreESP32.serial.disableRTS=true
i changed these lines in my boards.txt for the relevant modules and now the issue has become totally hit and miss
on some boards the serial monitor works, on others it doesn't
I am not a serial expert but to me getting this almost random outcome points to something a bit more serious than changing a couple of lines in boards.txt
if there is anyone here who knows a solution for this problem rather than a quick fix which might work could they please share it or is there somewhere else I should be registering this problem

thanks in advance to anyone who can help

Dave

Hardware Configuration

ESP32 & ESP32S3 using esp_now connecting nodes by wifi

Version

latest stable Release (if not listed below)

Type

Task

IDE Name

Arduin0 2.3.6

Operating System

Windows 11

Flash frequency

80Mhz

PSRAM enabled

no

Upload speed

921600

Description

if(Serial.available()) { in loop is never seen as true even when characters are typed in serial monitor

Sketch

void loop() {
  if(Serial.available()) {
    char c = Serial.read();
    if(c != 13) {
      kbdInput += c;      // add c to string
    } 
    else inptrdy = true;
    Serial << "serial ok c: " << c << "  kbdInput: " << kbdInput << 
    "  inputrdy: " << ((inptrdy)?"true":"false") << endl;
  }
  if(inptrdy) {
    Serial << "inptrdy true kbdInput: " << kbdInput << endl;
    if(kbdInput == "c") {
      Serial << "Keyboard commands:"    << endl <<
      "tables:       print nodes tables" << endl <<
      "restart:      restart this node"  << endl <<
      "proxy:        set this node to use a proxy" << endl <<
      "proxy table:  print proxy table" << endl <<
      "------------------------------------------" << endl << endl;
    } 
  }
}
// return character set to Carriage Return

Debug Message

if(Serial.available()) {
is never seen as true, hence there is never an output

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[SuGlider]

for no apparent reason the serial monitor on my boards (i have several nodes) stopped working

This is the issue, I guess.

Which board doesn't work (ESP32 or ESP32-S3)?
How exactly it doesn't work? Nothing is seen in the Serial Monitor? It doesn't open the Window?

I guess that the issue is realted to the S3 only.
ESP32 boards usually have a chip to convert UART to USB like the CP2102 or CH340 and those are always on as far a the board has power.

ESP32-S3 devkit has 2 USB ports. One is also connected to the UART port using a CH340/CP2102 chip. This port woudl never fail.
The second port is an USB port and it can work as HW Serial/JTAG ro OTG USB mode.
The mode is selected in the Arduino IDE Menu (board specific).

Please provide more information in order to help this issue.

[davejel]

SuGlider
the issue started shortly after Arduino started sending messages saying a setting had changed and the IDE needed to be restarted, at the time i did not relate the two but it is the only thing that changed before the issue started
the message from Arduino comes with no explanation, just the message to restart

"Which board doesn't work (ESP32 or ESP32-S3)?"
the ESP32S3 is working at the moment. Some ESP32's work others do not ???

"How exactly it doesn't work? Nothing is seen in the Serial Monitor? It doesn't open the Window?"
when i type characters in the serial window followed by return the output i should see in the serial monitor is not there
i have checked this and the issue is caused by:
if(Serial.available()) { never being true when i type characters followed by return

"The mode is selected in the Arduino IDE Menu (board specific)."
The ESP32S3 was not working, then for no apparent reason started working
The ESP32's some work and some do not, thats what makes the issue so confusing, it apparently has a random nature
if you need any other information please let me know

Dave

[SuGlider]

OK. This seems to be related to some update to the Arduino IDE.
I'll make some questions that may help:

1- What is the baudrate set in the Serial Monitor? ESP32 uses 115200.
2- What is the end of line character sent to the ESP32? It can be viewed in the Serial Monitor box at the left side of the baudrate box.
3- If you use S3 devkit board, please connect the UART marked port (written beside the USB board connector)
4- Please check if the correct Serial Port is selected in the Arduino IDE

The presented issue sketch isn't ESP32 Arduino compatible.
Serial has no << operator, therefore that sketch won't compile.
Anyway it expects a 0x13 \r (CR - Carriage Return) at the end of the received line.
It must be checked in the Serial Monitor to see if CR character is really sent when data is sent using the Serial Monitor text box.

[davejel]

1- What is the baudrate set in the Serial Monitor? ESP32 uses 115200.
115200
2- What is the end of line character sent to the ESP32? It can be viewed in the Serial Monitor box at the left side of the baudrate box.
carriage return
3- If you use S3 devkit board, please connect the UART marked port (written beside the USB board connector)
one is S3 devkit and I am using the correct USB connector
please note: at the moment the S3 is working (was not but is now) it is some of my ESP32Dev modules which are not working

4- Please check if the correct Serial Port is selected in the Arduino IDE
the correct serial port is selected Serial.print works on all modules

[SuGlider]

@davejel - At this time I understand that the S3 works correctly, but the ESP32 doesn't.
This is not related to the Arduino Core software.

It points to being related to the ESP32 board that may have some hardware failure.
If you have any UART-USB converter board there you may try to use it to check if the ESP32 Chip is fine / CP 2102|CH340 is working or the Board may have some bad track / connection.

Given that the S3 (UART port) is working correctly for sending and receiving bytes, I'd suggest using the S3 USB cable (that shall be good) for testing the ESP32. USB Cable may also be the source of the problem.

Using the same S3 USB port in the PC is also a valid test once the issue could be in the PC USB Connector as well.

In other words, the presented symptoms point to a Hardware problem.

[lbernstone]

disableDTR and disableRTS is never appropriate for the ESP32 (or really any ESP using UART) . Make sure those are set to false.
Set Core Debug Level to verbose. Try setting the baud rate to 9600 in both your firmware and in the Serial Monitor, upload and see if you get any output. Note that this should make the initial boot info garbled (it is fixed at 115200).
If you still aren't getting any serial output, but you are able to upload code without a problem, then you have a problem with the Arduino IDE. Uninstall and reinstall. If you get a message about missing permissions actually read the message and make sure you are giving the necessary permissions. You could also try to install Arduino 1.8.19 and see if there is a problem with new version.

[davejel]

IbernStone
thankyou at least you confirmed my fears about boards.txt, i have put it back to the original
setting baud rates to 9600 made no difference, i am now in the process of installing 1.8.19,
i will come back to you tomorrow and let you know how i get on
once again thanks for your interest

[SuGlider]

IbernStone thankyou at least you confirmed my fears about boards.txt, i have put it back to the original setting baud rates to 9600 made no difference, i am now in the process of installing 1.8.19, i will come back to you tomorrow and let you know how i get on once again thanks for your interest

@davejel - Are you able to upload a firmware to the ESP32?
If so, there is no issue with cables, ports and peripherals.

[davejel]

IbernStone
a big thank you, I have now confirmed that this is an Arduino 2 problem
the below code runs perfectly in Arduino 1.8.19 but has the original problem when run in 2.3.6
I will report the problem on Arduino issues
thank you again

Dave

`void setup() {
Serial.begin(115200);
while(!Serial);
Serial.println("Serial started");
}

String kbdInput = "";
bool inptrdy = false;
void loop() {
//-------------------
if(Serial.available()) {
char c = Serial.read();
if(c != 13) {
kbdInput += c; // add c to string
}
else inptrdy = true;
Serial.print("serial ok c: ");
Serial.println(c);
Serial.println("kbdInput: " + kbdInput);
Serial.println("inputrdy: " + inptrdy);
}
if(inptrdy) {
Serial.println("inptrdy true kbdInput: " + kbdInput);
if(kbdInput == "c") {
Serial.println("Keyboard commands:");
}
else if(kbdInput == "tables") { // print tables
Serial.println("printTheTables()");
}
else if(kbdInput == "restart") { // restart node
Serial.println("Power On Reset this node");
}

kbdInput = "";
inptrdy = false;

}
}
`

[SuGlider]

Closing this issue. Fell free to open it again.