About Nano TX LED

[minshun]

I wrote a piece of code that allows data to be transmitted via Serial as soon as the device boots up. When the USB is connected to the computer, the TX LED blinks continuously. However, when the USB is only supplying power (no data connection), the TX LED does not blink. What is the reason for this?

[runaway_pancake]

Is there a while in your sketch where it's waiting to find the Serial terminal ?

[sterretje]

I have no experience with the Nano Every. I know that it is different from the Classic Nano. One possible reason that I can think of is the way how the serial-to-usb converter works on the on your board.

The Nano Every has an intelligent serial-to-usb converter (SAMD11) that "knows" if the board is connected to the PC; not connected to the PC and it will not send data to the PC (and hence the TX LED will not flash). I've just tested this with an official Mega (also has an intelligent serial-to-usb converter (8U2 or 16U2) and the behaviour is the same as with your Nano Every.

The serial-to-usb converter (FT232, CH340) on the Classic Nano is not an intelligent converter and will just send the data.

[minshun]

I didn't do it, here is all my code.

void setup() 
{
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(13,OUTPUT);

}

void loop() 
{
  Serial.println("test");
  digitalWrite(13, LOW);
  delay(250);  
  digitalWrite(13, HIGH);
  delay(250);
  // put your main code here, to run repeatedly:

}

[sterretje]

In future, please post code using code tags as described in https://forum.arduino.cc/t/how-to-get-the-best-out-of-this-forum/679966#posting-code-and-common-code-problems

[minshun]

Thank you, I know what to do next time.

[minshun]

I'm sorry, I'm not sure about the model of the development board I have.
Here is the development board I am using.

I also believe it's the phenomenon you mentioned, because I experience the same issue when I use a computer without the driver .

[cattledog]

@minshun

I'm not sure about the model of the development board I have.

It looks like a Nano. It is not a Nano Every.

[sterretje]

OK, that looks like an official Classic Nano (with FT232 chip), not a Nano Every as shown below

Your topic has been moved to the correct section of the forum.

[sterretje]

I have a SparkFun RedBoard which also uses the FT232 chip as its converter and can confirm the behaviour. So I probably have been wrong about the intelligence of the FT232 and CH340. I can not easily test a clone Nano with CH340.

I've corrected my earlier reply.

[Brazilino]

Hi! Welcome to the Forum.

@minshun

When the USB is connected to the computer, the TX LED blinks continuously. However, when the USB is only supplying power (no data connection), the TX LED does not blink. What is the reason for this?

Shouldn't this happen because the Tx LED represents the transmission of data?
I mean: no serial connection = no data sent = Tx LED off.

[minshun]

This diagram is a circuit related to LEDs that I found online
I have a general understanding of why it won't light up

Currently, I have a non-original development board in hand, and it doesn't have this issue.