fried mirco processor??? ( L LED)

hello everybody, i need help your feedback about my Arduino problem. I was going power on via USB cable and external battery those are same showing L LED. Why it showing a L LED keeping turn on? what it does mean? i could not find the information Arduino's playground and "getting started with Arduino". Any one who knows the answer my question? thank you for your time

Hi, the state of the led depends on the sketch which is currently loaded on the Arduino. The sketch starts running as soon as you power the Arduino (after a short "boot" time). If it is a new Arduino and the led is blinking you have no reason to worry. Just be careful about the voltage of the external battery and how you connect it (barrel socket or power pins). How is the rest working?

Reset is still not working . It wont blinks or anything it just constant L LED. Same thing with exteral battery using 9 voltage power pins vin and ground into arduino and USB cable. Also I decided press a little longer hold reset button to see if L LED start blink but Its too stubborn.

It was suppose be once press reset start blinking. And now it does not start processing right.

Just forget the led, can you load a sketch? Does the computer see the arduino.
Reset always works, you just don't know what it is reaseting to.

Ok im going to forget led. I am using arduino uno r3 1.0.3 verison. I have error upload sketch code from blink example. It said from the following " avrdude: stk500-getsync (): not in sync:resp=0×00." The arduino and computer was on serial port COM 3. I went to my control panel, manager device unintalled COM3 and reinstall updated driver software from the files 1.0.3 verison and it shows back COM 3.

So the computer is not seeing the arduino. I assume it does not appere in the IDE's interface menu.
Then it does look like you have a non working arduino. Did you do anything that might have broken it?
Follow the normal test procedure outlined in the sticky post of this section.

Grumpy_Mike you are right,
I was going to plug USB on my computer and open the Arduino file the pop up said " Launch4j an error occurred while starting the application". I clicked ok. the sketch is working. so i decided go to back to my manager device properties , port setting, advanced to change the COM to COM 4. see if Arduino can communicate with computer. i went to my sketch program tools, serial ports, it does showing the bold letters or existed. i was able to be set up for COM 4. i am no longer using COM 3. hmm... it s so obviously the computer is seeing the Arduino. is Arduino see computer?

i got suspect what happened to my Arduino is that i was working on my led strip 3825 they are required 12 volts on my breadboard it excellent work for couple days! then somehow i was working on my own PCH i was adding 47uf and NPN transistor on each RGB into PWM pin. and i was testing somehow screw up i was not sure if it does effect by duty cycle. i did not set up the variable code so.

is Arduino see computer?

What sort of arduino do you have? Most have two chips on to communicate with the computer and the other to do the sketch running.
It is possible that this second one is not working so while the computer and arduino see each other there is nothing for that chip to see on the arduino side.

  1. Do a loopback test to confirm this.
  2. You could try reburning the botloader on your arduino, although you need another arduino to do this or a programmer.

i using Arduino UNO. I launched IDE 1.0 and 1.0.1 without Launch4j error. then i go to Arduino tools, burn boot-loader i got this both error of the following " avrdude: usbdev_open(): did not find any USB device "usb" ".

i am new to this. so you are telling me i need get another Arduino such as new ATMEGA 328P-PU from or isp usb programmer from ebay? once i get them so do i need to burn-loader on my old chip to back work?

i found this information i have not read this as yet. i am going to read it now. thank you for your big help!

i am new to this. so you are telling me i need get another Arduino such as new ATMEGA 328P-PU from or isp usb programmer from ebay? once i get them so do i need to burn-loader on my old chip to back work?

To burn a bootloader on another arduino board or just the 328P chip wired properly on a breadboard does require a hardware programmer, which can be an arduino board running the arduinoISP sketch.

Be sure if you buy a AVR programmer on E-bay that it’s one that will work as one of the programmer choices shown in the IDE programmer selection menu.

Here is a cheap one I bought recently that works:


Just to say that reburning the boot loader is not guaranteed to fix it, it is a long shot but it works sometimes.
If you buy a blank processor then you will need to burn a boot loader into it.
You need to have done the loopback test successfully first in any case otherwise burning the boot loader will not help you.

I posted this recently. Reply #15 might help. Or not.

Good luck!