ESP board resets when opening com port

[der_Phil]

Hi experts,

I use a ESP Wroom 32 on a ESP32 Feather Board
see: https://www.adafruit.com/product/3707

With this, I managed to rebuild this project: https://learn.adafruit.com/thermal-came ... y/overview
I somehow want to extend the project, by saving images on aSD card and transfer them over the USB connector...hence I establish a serial connection using a com port.

My question is a follows.

Using the Arduino IDE I can open/close the com port as expected.

When I open/close the com port with 3rd party software, the board resets...why?

I found this in the internet for an Arduino:
https://tushev.org/articles/arduino/22/ ... ens-closes

You should set Data Terminal Ready (DTR) parameter for port to false\disabled. Without that signal, Arduino will not reset each time the port is opened or closed.

Code: Select all

SerialPort p = new SerialPort(args[1], 9600);
p.DtrEnable = false;
p.Open();
p.Write(args[0]);
p.Close();

Is this also a possible solution for the ESP board?

Thank you,
Phil

[thethinker]

Hi experts,

I use a ESP Wroom 32 on a ESP32 Feather Board
see: https://www.adafruit.com/product/3707

With this, I managed to rebuild this project: https://learn.adafruit.com/thermal-came ... y/overview
I somehow want to extend the project, by saving images on aSD card and transfer them over the USB connector...hence I establish a serial connection using a com port.

My question is a follows.

Using the Arduino IDE I can open/close the com port as expected.

When I open/close the com port with 3rd party software, the board resets...why?

I found this in the internet for an Arduino:
https://tushev.org/articles/arduino/22/ ... ens-closes

You should set Data Terminal Ready (DTR) parameter for port to false\disabled. Without that signal, Arduino will not reset each time the port is opened or closed.

Code: Select all

SerialPort p = new SerialPort(args[1], 9600);
p.DtrEnable = false;
p.Open();
p.Write(args[0]);
p.Close();

Is this also a possible solution for the ESP board?

Thank you,
Phil

If you look at the Schematic of the board you are talking about you can see that the RTS (Ready to send) pin of the USB<>SERIAL converter can also reset the chip, so you would have to disable that too.

[rdaf2014]

I had similar problem. Each time I connected to my ESP32 from putty (serial), the ESP "rebooted".
I changed the flow control settings in Connection/serial from DSR/DTR to RTS/CTS.
Know i can connect and disconnect to my ESP32 without anoying resets.