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USB Thumb Drive Causing Reboots

GeorgeIoak

I know this has been discussed both here and over on the RPi forums. A lot of talk has gone into the power rails but I haven't seen anyone definitely finding what actually causes the RPi to reboot. I have a "newer" Rev 1 board which has zero ohm resistors at the USB power lines. By adding extra capacitance I can eliminate the reboots but the drive is not always enumerated.

 

Measuring on the scope I can see the 5V rail dip a bit but the 3.3V and 1.8V appear to be stable. I'm powering the RPi through the GPIO header so that would bypass the F1 fuse at the incoming rail.

 

I'm wondering if I'm missing something glitching on the 1.8V rail or is this some type of kernel error causing the reboot? I don't see anything in the log files but I'm also not a Linux guru so maybe I'm not looking in the right places. I did ask this question the other day on the RPi forums but it seems like more engineers hang out here so I'm hoping to eliminate the fluffy comments and opinions.

 

If I missed this somewhere I apologize but hope you'll point me to the right thread.

 

I haven't torn apart a Roku2 but I see that it uses the same LAN9512 and BCM2835 so I'd be curious to see how they did their layout. I can see limiiting the current with the poly fuses but once those are gone and you have a supply with plenty of current and a strong rail I don't see why inserting a drive should cause a reboot. Perhaps this is all related to the problem of the LAN9512 1.8V output tied to the RPi 1.8V rail?

 

Looking forward to hearing what this community has to say!

Parents

  • I had a similar issue with USB devices while powering the Raspberry Pi from the GPIO headers.  I was able to overcome the issue by directly connecting the 5V and GND of the GPIOs to the 5V and GND of the USB.  The attached image is of a modified rev1 board, but should also work the same for the rev2 board.  Not exactlty the most elegant of solutions, but it was just the quick and dirty fix I needed.

     

    image

Reply

  • I had a similar issue with USB devices while powering the Raspberry Pi from the GPIO headers.  I was able to overcome the issue by directly connecting the 5V and GND of the GPIOs to the 5V and GND of the USB.  The attached image is of a modified rev1 board, but should also work the same for the rev2 board.  Not exactlty the most elegant of solutions, but it was just the quick and dirty fix I needed.

     

    image

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  • in reply to Former Member

    Michael Mitchell wrote:

     

    I had a similar issue with USB devices while powering the Raspberry Pi from the GPIO headers.  I was able to overcome the issue by directly connecting the 5V and GND of the GPIOs to the 5V and GND of the USB.

    It's kind of scary that adding the wires fixed the problem.  After all, with a rev 2.0 or an Ohmless rev 1.0 the GPIO 5V and GND pins are directly wired to the USB jack according to the schematics.  The fact that adding wires changes behaviour suggests that the 5V trace to GPIO is pretty narrow.  Sure would be nice to see those Gerbers image