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[on:]

Hey Guys,

i'm working for a few hours at the communication between my PC and a Leonardo, but I have a big problem to send data from Arduino to the PC. At first I thought I did a mistake at the serial-read or event function in visual basic. But now I figured out, that the Arduino doesn't send data, if I activate the com-port from my VB-program. However, if I use the standard Arduino serial monitor, I get sent data and the TX LED is blinking. If I'm using my VB script, I can't get a blinking LED, however, the communication in the other direction works well. For example I can send data to the Arduino and the RX LED blinks.

Now the question: Is there any function, I have activate to get the Arduino in a sending mode. I could imagine, It could something have to do with “handshaking”???


Thanks for the help.

[Reply #1 on:]

The Leonardo requires that the DtrEnable flag be true. Are you setting it?

[Reply #2 on:]

No!
I'll test it in the evening.

Thank you.

[Reply #3 on:]

works perfectly,

mille grazie!

[Reply #4 on:]

For future reference, perhaps you could post your VB code for opening the port.

[Reply #5 on:]

If I try to use a Terminal program with an Arduino Uno (R3 SMD) under windows 7, I get the message: "The port is not available".

However, when I use the Monitor Serial, I don't get the error and all the data flow fine, so nothing is locking the port....is this the same issue?

Thank you

[Reply #6 on:]

is this the same issue?

No.

However, when I use the Monitor Serial, I don't get the error and all the data flow fine, so nothing is locking the port

You aren't trying to use the Terminal program at the same time as the Serial Monitor, are you? Have you closed the IDE?

[Reply #7 on:]

is this the same issue?

No.

However, when I use the Monitor Serial, I don't get the error and all the data flow fine, so nothing is locking the port

You aren't trying to use the Terminal program at the same time as the Serial Monitor, are you? Have you closed the IDE?

Yes, of course I have tried to connect via Terminal after closing the IDE.
It happens the same to me, when using the programming port with the Arduino Due, I can only connect to the Native USB.

What is it then?

[Reply #8 on:]

It happens the same to me, when using the programming port with the Arduino Due, I can only connect to the Native USB.

That would be logical. The programming port is for, well, programming the Arduino. You aren't programming the Arduino from the Terminal application, are you?

[Reply #9 on:]

It happens the same to me, when using the programming port with the Arduino Due, I can only connect to the Native USB.

That would be logical. The programming port is for, well, programming the Arduino. You aren't programming the Arduino from the Terminal application, are you?

I am not, but wouldn't I be able to communicate to Arduino Uno via Serial.print() and Serial.read() commands?

I don't understand why the port is not available when I try to open it from another program different from Serial Monitor (which is supposed to be the same).

[Reply #10 on:]

communication between my PC and a Leonardo

Just from looking at other code, the leonardo has some special requirements as to its serial port. probably nothing to do with the comport issue on your pc, but there is something different. If you are using windows, have you looked in device manager at the comport settings for different comports and such? 

[Reply #11 on:]

the leonardo has some special requirements as to its serial port.

The only difference is that DtrEnable must be set to true.