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Topic: Arduino Leonardo: problem with Serial Communication (Read 682 times) previous topic - next topic

Brunez3BD

Hi everybody! I've bought my new Arduino Leonardo, it's all ok with the drivers and I can upload the sketch... BUT THE SERIAL COMMUNICATION WON'T FUNCTION.
I've windows 8 and the serial monitor remain clear for all the time. I've seen that if I send anything to the Arduino from the serial monitor the RX led blink, but there is no response... the monitor remain white. Also with a simple sketch like Example -> Communication -> Graph.
I've set the COM, the monitor and the sketch at 115200 baud, I need help because I have this problems for a month..
Thank you very much

James C4S

Right after the Serial.begin() add:

while (!Serial);

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Brunez3BD

Already done... But still not work..But I've seen a thing:
when i disconnect and riconnect the arduino via USB it first appear on COM 9 ("Arduino Leonardo Bootloader"), then after a few seconds it automatically disconnect and reappear on COM 10 like "Arduino Leonardo".
If I open the serial monitor in the first seconds when it is on COM 9 I can send a character and on the serial monitor appear a "?", but still no send the message contained in the sketch

superlol

I think that's due to the bootloader of Leonardo.
When you first connect the board the first com port you see is the one used to upload the bootloader then thessecond one is the communication you get through the Serial command.
So if you have to upload a new sketch use com9 but if you have to communicate with the board use com10

Keep in mind to keep the serial monitor closed untill you see the com10 port, then choose the right port on the arduino ide and only after this open the serial monitor. If you keep the serial monitor open and a new com port is added I saw that the ide doesn't show the new port in the menu.
Of course when you have to upload a new sketch you must select the com9 port on the ide.

Anyway this is strange, try to delete and re-install the driver of the board. Do this while the board is unconnected
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Brunez3BD

I can't upload sketch using COM 9 because it remain only for a few seconds. I use COM 10 and it works fine, I use COM 10 also for Serial communication but still not working.. Driver reinstalled with board unconnected but no change

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