Hi,
what's wrong with this situation?
Thanks
Adam
This does not necessarily indicate any problem.
The first thing to understand is that the color of the LEDs doesn't have any significance. They don't change color or anything. It is only whether the LED is on or off that is important. They are red only because the manufacturer of the board chose to put red LEDs on the board.
The LED marked "ON" is the power indicator, so this only means that the board is powered. So this LED being on is expected whenever you have the board plugged in to the USB on your computer or otherwise powered.
The LED marked "RX" indicates the state of pin 0 on the board (RX). The RX pin is usually used for serial communication with your computer ("RX" stands for "receive"), but it is also possible to use it just like any other pin on the board. So the "RX" LED could be on if the board is receiving serial communications from the computer, or just because the sketch that is currently running on the board sets the pin to an output state that causes the LED to be powered. So this being on is maybe slightly unusual, but definitely not a sure indication of a problem.
The LED marked "L" is connected to pin 13 on the board. So it will be on the sketch that is currently running on the board sets the pin to an output state that causes the LED to be powered. So this being on is not in any way unusual.
So all this is to say that the LED do not indicate anything is wrong with the situation. Was there something else that made you thing something was wrong? If not, then you can get back to having fun with Arduino!
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Thank you in0.
the thing is my computer stuck there and can't do uploading.
changed another one UNO, uploading OK.
You are welcome. I'm glad to hear you are able to continue with your progress.
If you do decide to try to get the original board working some time, we can try to help you out.
The truth is that sometimes the "can't upload" symptom means that there is permanent physical damage to the board, usually caused by exposing the electrical components to conditions outside their rated specifications (AKA "letting out the magic smoke"), but in other cases the upload failure is a simple software or firmware misconfiguration and we are able get the board back up and running.
2 Likes
Thank you in0.
actually, it is pc stuck, I don't even have chance to move my mouse to click upload.
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