Hello,
I have this problem: i connected an rfid reader to my arduino uno, but then i saw that ground was not connected to the breadboard so i suddenly disconnected all (first 3.3 v from arduino, then usb) and i think i got the mess...
Now my arduino uno has the same symptoms described in this post: the green led lights on, the yellow led blink 3 times when the board is powered on (actually it blink 3 times quickly, then is off for about 500 ms and the blinks another time). If i press the reset button the led does the same thing.
Is my board in the same condition of the boards of the linked post? can i try to program it via FTDI? And, the more important question, is the usb connection definitely dead or is there any way to get it to work again?
Thanks a lot for your support
You don't state if you still can upload or not. Assuming not:
-
If your board has the 16U2 micro that does the TTL-to-USB conversion, you can try to fix it; I've never done that but as far as I know you need a programmer for that or another Arduino that can act as a programmer.
If your board does not have the 16U2, it can't be reprogrammed.
-
Yes, it usually is possible to program the 328P using a FTDI cable assuming that the damage is limited to the USB-to-TTL adapter. The led behaviour shows that the boot loader in the 328P is still working.
Thanks for your answer: no, i can no more upload to the board.
This is my board and I thinks it has 16U2 chip (is that in the red circle?).
How should I reprogram this (I have an Arduino nano in my hands)? If i reprogram the 16U2 chip it will enable again the usb port?
If i use the FTDI cable to program 328P, instead, the usb connection won't works again, right?
Thanks again for your support
I noticed another thing: for two or three times Arduino was recognized, i tried to upload the sketch for internal led blinking and i got it, but the led didn't blink, then i reconnected the card and it was recognized again but arduino ide gave me some error about clock and then my pc freezed! when i rebooted the card was no more seen by the pc and i got the usual messages
[ 1122.210896] usb 1-4: new full-speed USB device number 65 using xhci_hcd
[ 1122.338950] usb 1-4: device descriptor read/64, error -71
[ 1122.574893] usb 1-4: device descriptor read/64, error -71
[ 1122.810727] usb 1-4: new full-speed USB device number 66 using xhci_hcd
[ 1122.938768] usb 1-4: device descriptor read/64, error -71
[ 1123.174771] usb 1-4: device descriptor read/64, error -71
[ 1123.282937] usb usb1-port4: attempt power cycle
[ 1123.934884] usb 1-4: new full-speed USB device number 67 using xhci_hcd
[ 1123.935295] usb 1-4: Device not responding to setup address.
[ 1124.143153] usb 1-4: Device not responding to setup address.
[ 1124.350896] usb 1-4: device not accepting address 67, error -71
[ 1124.478673] usb 1-4: new full-speed USB device number 68 using xhci_hcd
[ 1124.478932] usb 1-4: Device not responding to setup address.
[ 1124.686976] usb 1-4: Device not responding to setup address.
[ 1124.894905] usb 1-4: device not accepting address 68, error -71
[ 1124.895065] usb usb1-port4: unable to enumerate USB device
i tried to enter dfu mode by shorting two of the icsp pins but nothing happened, i think something inside got fried...
Outside my area of expertise, sorry.
It's indeed a 16U2; you can recognise that by the square shape (and the jumpers next to it).
Very strange: i reconnected arduino uno to pc and it was recognized at the beginning, then gave the usual errors in dmesg. After some unplugs and replugs i got a "stable" connection and was able to upload the internal led blink sketch with Arduino IDE, then it went down with errors again. Then I tried to reconnect again for a few times and, when finally it was recognized by pc, arduino internal led began to blink!
now i have plugged a 9v DC power adapter in the barrel jack and i'm monitoring its behaviour, and it is blinking since 10 minutes without any problem.
I think could be some problem or in usb cable or in usb connector...
You could try to re-flow the USB connector if you have a fine soldering iron and the skills.
Another USB cable is always recommended to try.
