user13832: I have an arduino that I programmed a PWM signal on pin 5. When I power the arduino with 12v or USB5v, pin 5 has the PWM signal. Iam checking it with a oscilloscope. Oddly enough the arduino is not recognisable to a windows PC or MAC, the device never shows up on the usb. The LED on the device seem to give all the right signals. The Green ON LED is on. And the L LED is also on. The program is not using serial so the RX and TX are not on.
When I try another Arduino it works fine.
What could I have broke? I am guessing the ATmega328 is fine?

user13731: Just a guess, if anything else work fine, my (first) guess would be the serial to usb adapter. I damaged one a while ago on a breadboard but also dont know how. But it could also be almost everything else. The pwm sketch, in which language is it written and burned? Does the Atmega have a bootloader on it?

13832: <p>I have an arduino that I programmed a PWM signal on pin 5. When I power the arduino with 12v or USB5v, pin 5 has the PWM signal. Iam checking it with a oscilloscope. Oddly enough the arduino is not recognisable to a windows PC or MAC, the device never shows up on the usb. The LED on the device seem to give all the right signals. The Green ON LED is on. And the L LED is also on. The program is not using serial so the RX and TX are not on.</p>

<p>When I try another Arduino it works fine.</p>

<p>What could I have broke? I am guessing the ATmega328 is fine?</p>
 13731: <p>Just a guess, if anything else work fine, my (first) guess would be the serial to usb adapter. I damaged one a while ago on a breadboard but also dont know how. But it could also be almost everything else. The pwm sketch, in which language is it written and burned? Does the Atmega have a bootloader on it?</p>
