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Feather 32u4 Basic Proto... USB error
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Please be positive and constructive with your questions and comments.

Feather 32u4 Basic Proto... USB error

by MogaRaghu on Sun Apr 08, 2018 4:30 am

I followed all the steps to connect the subject board ( Feather 32U4 Proto) and selected the same in boards. When i plugged the USB i got a brief message saying that the PC is trying to install the Feather 32U4 board and then the process failed. Ever since, when ever i try to plug in, I get a message saying something like like "USB Device malfunction. Device Descriptor failed "

Is the module bricked once and for all ? Any way to get it back to talk to my PC ? ( Earlier i had installed the WIndows drivers for Adafruit boards ) . I am using a Windows 10 machine and use the Arduino with all other boards like Nano / Huzzah ESP8266 / Mo Feather etc

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Re: Feather 32u4 Basic Proto... USB error

by MogaRaghu on Sun Apr 08, 2018 9:29 pm

Maybe I should add this .. Initially when i connected the fresh module to PC, it was identified and a COM port allocated. And since by then i did not have the Adafruit AVR boards in my IDE , i chose Arduino Leonardo ( since that also uses the 32U4 MCU ) and downloaded the blink code. It worked.

Would the above mucked up the module ? ( I thought boot loaders are only Read Only after they are burnt ?)

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Re: Feather 32u4 Basic Proto... USB error

by adafruit_support_mike on Mon Apr 09, 2018 1:48 am

The bootloader should be fine. That memory is locked so the bootloader can't alter itself.

Does the Feather's red LED pulse when you click the reset button?

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Re: Feather 32u4 Basic Proto... USB error

by MogaRaghu on Mon Apr 09, 2018 2:12 am

adafruit_support_mike wrote:The bootloader should be fine. That memory is locked so the bootloader can't alter itself.

Does the Feather's red LED pulse when you click the reset button?


So the boot loader is locked ...Great .. that's what i wanted to hear ! And today i tried many combinations of Double clicking the reset button and suddenly the PC decided to accept the interface and allocated a COM port !! So peace. ;-)

But i am a bit curious on the Port allocations : The Serial sends out data to the IDE Monitor on COM20 which is the only port that shows up on the IDE. Programming happens on COM21 and it does not show up either on the IDE or the Device Manager of PC. The Device Manager just reports Composite Generic USB - whatever it means.

Sorry if its all very basic queries - i am new to this kind of USB module and hence the doubt.

thanks for your prompt response.

MogaRaghu
 
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Re: Feather 32u4 Basic Proto... USB error

by adafruit_support_mike on Tue Apr 10, 2018 3:56 am

Glad to hear the board is working for you again.

The changing COM port is a side-effect of how Windows handles USB.

The ATmega32u4 handles USB internally, so the bootloader needs to set up a USB connection to upload firmware, then tear that connection down before passing control over to the code you've uploaded. If your code wants to use the Serial interface, the microcontroller needs to set up another USB connection for that.

Every time a USB device connects to the hub, one part of the setup process involves finding out what the device can do and having the OS allocate resources for that. That takes time, so the OS saves the information about the connection so it can just load a preconfigured connection the next time that device is plugged in. Windows identifies those as COM ports.

The bootloader's USB connection is different from the one your code will use, so to Windows, it looks like one device is being unplugged and a new one is being plugged in. It flips from one COM port to the other depending on what code is active on the microcontroller at the time.

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Re: Feather 32u4 Basic Proto... USB error

by MogaRaghu on Tue Apr 10, 2018 5:18 am

That was a great explanation on how the Native USB is handled. Thanks.

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Re: Feather 32u4 Basic Proto... USB error

by MogaRaghu on Tue Apr 10, 2018 12:56 pm

I have one final request with the module ... can i control the ENable pin by one of the MCUs pins to shut down ?

Actually the application is a battery based one and every time the 32U4 powers up, i just need it for 10 seconds and then i enter sleep mode to conserve power. But still the 3V3 regulator is on line and i would like to shut that down too when the MCU goes to sleep. Then when the user want to wake up, he will momentarily take the EN pin high.

Is there any way to do this ??

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Re: Feather 32u4 Basic Proto... USB error

by adafruit_support_mike on Thu Apr 12, 2018 2:54 am

MogaRaghu wrote:I have one final request with the module ... can i control the ENable pin by one of the MCUs pins to shut down ?

Yes, but not the way you want it to work.

The microcontroller can pull En low and shut off the voltage regulator, but only while it's running. Once you shut off the regulator, the microcontroller will shut off and release En, the regulator will come on again, and the microcontroller will reboot.

It sounds like you want a circuit like our Push-Button Power Switch:

https://www.adafruit.com/product/1400

Pressing the button turns on the power, and pressing it again shuts off the power. There's also an OFF pin that a microcontroller can use to turn off the switch. Sending the PBPS's OFF pin high will turn it off, and the rest of the PBPS will keep the power shut off until someone pushes the button again.

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