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I have just programmed a new micro, loaded the basic blink code in it. After that neither my laptop, nor my desktop sees it anyway with the following usb error:

Fri Apr  1 14:32:01 2016] usb 1-2: device descriptor read/64, error -62
[Fri Apr  1 14:32:01 2016] usb 1-2: device descriptor read/64, error -62
[Fri Apr  1 14:32:02 2016] usb 1-2: reset full-speed USB device number 8 using ohci_hcd
[Fri Apr  1 14:32:02 2016] usb 1-2: device descriptor read/64, error -62
[Fri Apr  1 14:32:02 2016] usb 1-2: device descriptor read/64, error -62
[Fri Apr  1 14:32:02 2016] usb 1-2: reset full-speed USB device number 8 using ohci_hcd
[Fri Apr  1 14:32:03 2016] usb 1-2: device not accepting address 8, error -62
[Fri Apr  1 14:32:03 2016] usb 1-2: reset full-speed USB device number 8 using ohci_hcd
[Fri Apr  1 14:32:03 2016] usb 1-2: device not accepting address 8, error -62
[Fri Apr  1 14:32:03 2016] usb 1-2: USB disconnect, device number 8
[Fri Apr  1 14:32:03 2016] usb 1-2: new full-speed USB device number 9 using ohci_hcd
[Fri Apr  1 14:32:04 2016] usb 1-2: device descriptor read/64, error -62
[Fri Apr  1 14:32:04 2016] usb 1-2: device descriptor read/64, error -62

If I push the reset button on it it comes back a bit then disappears again:

22620.495256] usb 1-2: New USB device found, idVendor=2341, idProduct=0037
[22620.495263] usb 1-2: New USB device strings: Mfr=2, Product=1, SerialNumber=0
[22620.495268] usb 1-2: Product: Arduino Micro   
[22620.495272] usb 1-2: Manufacturer: Arduino LLC
[22620.497393] cdc_acm 1-2:1.0: ttyACM0: USB ACM device
[22627.966141] usb 1-2: USB disconnect, device number 32
[22628.432089] usb 1-2: new full-speed USB device number 33 using ohci_hcd
[22628.572111] usb 1-2: device descriptor read/64, error -62

Anybody experienced this? I have tried to reconnect it multiple times to both computers, even tried a new cable doesn't help.

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  • the AVR chips can be programmed via spi and sometimes serial, which means not via usb, if you get in a state where the usb is not usable. you may be at or close to that state.
    – old_timer
    Commented Apr 1, 2016 at 14:20
  • This means, you have not enough power on the USB bus. What does your sketch do? Are there any devices attached to the Arduino? Did you check with another cable?
    – moestly
    Commented Apr 1, 2016 at 17:04
  • Single processor for sketches and USB communication. The Leonardo and Micro differ from other Arduino boards in that they use a single microcontroller to both run your sketches and for USB communication with the computer. I don't see what else would you need to put into the basic blink example, if there is something board specific the compiler should put that in not you.
    – user19877
    Commented Apr 4, 2016 at 8:47
  • the AVR chips can be programmed via spi and sometimes serial, which means not via usb - that's not correct. The Micro has a USB interface and is intended to be programmed by it.
    – Nick Gammon ♦
    Commented Apr 4, 2016 at 21:32

2 Answers 2

Reset to default
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The USB part of the Atmega32U4 needs quite a bit of software to operate correctly, which is either not included in the basic blinky example or you got a binary for a different Arduino model.

The syslog looks like there is a bootloader present after Reset for a couple of seconds..

[22620.497393] cdc_acm 1-2:1.0: ttyACM0: USB ACM device
     ^
[22627.966141] usb 1-2: USB disconnect, device number 32
     ^

.. which shuts down and starts blinky. This is documented on the ArduinoBoardMicro page.

Re-flashing the chip is a bit tricky in this state, as you must press the reset button at the "right" time just before the software wants to access the chip.

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If I push the reset button on it it comes back a bit then disappears again:

That's exactly how it works. The Micro enumerates as a Serial interface for a couple of seconds after reset, enough time for you to upload a new sketch. If you don't upload in time, and unless your code specifies a serial port, the serial interface goes away. Blink doesn't use a serial port.

You need to quickly press and release Reset at the exact moment that the IDE says it is uploading, and the board should then detect the new sketch.

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