Nano serial com issue

Projects General Guidance
21

Except earlier earlier you said

which is not what will happen

22

I don't get it. The Nano I have does the following.

  1. Power it on, plug in USB cable.
  2. On PC, open serial port to Nano USB com port, then send :V# to com port.
  3. Nothing comes back from Nano. Serial port monitor on PC shows command went out but nothing came back.
  4. Start over with out doing anything to the Nano. Exit PC program.
  5. Start PC program, open com port to Nano, send :V# to com port, there no delay between opening the com port and then sending the command.
  6. Nano returns Ok# to PC program. Data received.
  7. The Nano now works as expected.

I can also not end the PC program just close the com port, reopen it, send the command. Works.

Again my problem is that the Arduino A000005 Nanos I have do not see the first serial data sent to them after they are first powered on and the data is sent right after a connection is made to the serial port. I find a 2 second delay in sending the data will work. Anything shorter will not. Only after power on does this happen. Does not happen on IoT and UNO.

23

Added this to my code to turn on the internal LED when serial data is available.

  if (Serial.available() > 0)
  {
    digitalWrite(LED1, 1);          // turn on internal LED
    inchr = Serial.read();

It does not turn on when I connect after power up.
Works at the very next connect.

Looks to me like the Nano has a design problem and most likely will never be fixed.

24

The explanation in reply #19 is ironclad. There is no way that can work. Go through the explanation slowly and follow along.

25

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