My UNO R3 has the yellow light constantly lit all of a sudden and i can't upload to the board.
Yesterday when i used it last time it worked fine and the yellow light was blinking as it suppose to.
The COM port works fine, i have checked that in Terminal.
But when i tried it today it has this problem, i haven't done anything that would cause this problem.
The Arduino IDE outputs the following message:
System wide configuration file is "C:\Program Files\Arduino\hardware\tools\avr/etc/avrdude.conf"
Using Port : COM3
Using Programmer : arduino
Overriding Baud Rate : 115200
avrdude: ser_open(): can't open device "\.\COM3": A device attached to the system is not functioning.
..............................................
So what is the exact problem and how do i fix it? Thanks in advance.
I have a brand new Arduino Uno R3 with the same problem. the Yellow light is on continuously. I have powered it with an external power supply and just using the USB connector from my laptop. either way i get the same results. I thought maybe it was because it wasn't programmed yet, I connected a RTC board I built and downloaded a program to set and display time. the program loaded and ran without an issue, but the yellow light is still on.
I have a second Arduino Uno R3 and the green light comes on once it has booted.
I tried removing and re-installing the chip, but that had no effect. I really don't want to mess with the bootloader, since it appears to be functioning.
The Arduino UNO has four LEDs. One is the Power led near the ICSP header. It stays on whenever the board has 5V power. There is one marked "L" near Pin 11 that is connected to Pin 13. It is supposed to be ON when Pin 13 is HIGH and OFF when Pin 13 is LOW. The other two LEDs are the RX and TX LEDs near the 16u2 chip that does USB-to-Serial. They blink as characters are sent and received.
Which LED are you talking about? If it is the one marked 'L' can you blink it with the Blink example sketch?
In my case it is the LED marked "L", and yes, I can blink it using the blink example Sketch. The best I can tell everything is working properly on my Uno R3. I thought the LED color had some significance as to the state of the device. Apparently that is not the case and they simply used Yellow or Amber LED's on this board rather than Red or Green.
Would it kill the Arduino hardware folks to improve the silkscreen around the LEDs on the arduino uno?
The fact that we get questions about the LEDs, where there is confusion about what LED means what or does what, on an almost daily basis, is a clear indication that the silkscreen is not successfully communicating the purpose of each LED. I think the pin 13 LED should be labeled more clearly - maybe even "LED (Pin13)" or something, and the power LED needs to be clearly marked as such. Maybe that would help the confusion - of course, most people are using clones anyway so maybe this wouldn't help so much...
@reholt:
So you can blink the LED from the sketch. So it sounds like it's working fine? Or is there something about it's behavior that is not what you expect?
my feedback is, the "L" led being HIGH by default is certainly not what i would expect, but so it is..
are all brands like this? or just my clone?
On an original Uno (from arduino.org), the pin13 LED is on after reboot. On my Sparkfun Redboard, the LED is off after reboot.
On the Redboard, the LED is directly connected to pin 13 (using resistor). As the pin is an input, not enough current can flow out of the pin to have the LED light up.
On the Uno, the LED is connected via a LM358 which might make a difference compared to a the Redboard. At the moment that I make pin 13 an output, the LED goes off.