Power problems

[Paul Chvostek]

Hi all.

I've got a C3 board that I purchased in late 2009. I tried for the
first time recently to plug it into a 5V power supply (I've been using
the OTG port), and found that it wouldn't start. The lights come on
and flicker as if the unit is trying to boot, but nothing shows on the
console, not even U-boot.

Is this something that can be debugged? How would I start? Or does
it sound like a hardware problem?

Thanks.

[freddyglima]

I would suggest you to take a look in your booting SD card and make
sure you it is alright.

Two ways for you to make a new SD card and test your board again:

http://code.google.com/p/beagleboard/wiki/BeagleboardRevCValidationv3
http://code.google.com/p/beagleboard/wiki/LinuxBootDiskFormat

[Gerald Coley]

What is the current rating on your 5V power supply?

 

Gerald

 

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[Paul Chvostek]

On Jul 5, 2:28 pm, freddyglima <freddygl...@googlemail.com> wrote:
> I would suggest you to take a look in your booting SD card and make
> sure you it is alright.

The problem happens prior to the SD card being accessed. As I said,
*nothing* comes across the serial console, not even an autoboot
attempt on NAND when the SD card is not present.

On Jul 5, 4:57 pm, Gerald Coley <ger...@beagleboard.org> wrote:
> What is the current rating on your 5V power supply?

I've tried a variety of power supplies, from 1A to 2.4A. Voltages
range from 5.06 to 5.18 vDC unloaded.

Oddly, the board will boot only when powered on the OTG port plugged
into a powered hub, but I've discovered that the hub in turn has to be
plugged in to a host.

And the behaviour with non-OTG 5V or a disconnected USB host is the
same - the three on-board LEDs behave "normally", but I see no serial
console.

Thanks for helping me debug this. I'd really like to confirm whether
I have a broken board before I decide whether to purchase a
replacement. :-/

- Paul

[Gerald Coley]

I think you need to take it a step at a time. Please provide answers for each question. Just work with the 5V DC supply in this arrangement to remove one whole set of variables.

 

(1) If the LEDs are correct, then you are booting.

(2) I suggest you read Section 13 of the System Reference Manual and make sure that you have the correct serial cable connections and that everything is inserted corectly, ribbon cable not installed backwards. Does this all check out OK?

(3) Make sure that you have all components in your setup, HUBs, Beagle, Monitor, and PCs all connected to the same power strip so you can be sure that you have a common ground arrangement. Is this all correct?

(4) Check the voltage of the 5V supply when it is plugged into the board. What do you measure?

(5) Let me know how the LEDS behave with and without the SD card installed.

(6) Let me know how the LEDS behave when you have the SD card installed and when you press and release the RESET button while the User Button pushed.

(7) Has the board ever worked for you? You seem to say it works on OTG, but it is not clear. It sounds like it boots from a powerd HUB. If the HUB is not powered, then it must be plugged into a PC or there is no power.  Some PCs cannot deliver the full power requiremnts even though they should.

 

Gerald

 

--

[Paul Chvostek]

On Jul 7, 10:03 pm, Gerald Coley <ger...@beagleboard.org> wrote:
> I think you need to take it a step at a time. Please provide answers for
> each question. Just work with the 5V DC supply in this arrangement to remove
> one whole set of variables.
>
> (1) If the LEDs are correct, then you are booting.

Okay, my bad. I had assumed that if I wasn't seeing any serial
console traffic, then the unit was not booting. I bought an HDMI
cable today and connected a monitor to the board, powered up with a 5
V adapter, and lo and behold, I saw U-boot and kernel boot messages,
and eventually an Angstrom login prompt came up on the (HDMI) screen.
I then plugged in a USB Ethernet interface and rebooted, and was able
to SSH in.

So ... I see U-boot on the serial console if a monitor is plugged in
to HDMI *or* if the OTG is plugged in to a host.

Very sorry I didn't think to investigate with an HDMI monitor before;
it didn't occur to me that lack of serial console output could mean
anything other than the unit not working.

But I'll answer a couple of the still-relevant points for good
measure...

> (2) I suggest you read Section 13 of the System Reference Manual and make
> sure that you have the correct serial cable connections and that everything
> is inserted corectly, ribbon cable not installed backwards. Does this all
> check out OK?

My serial cable and other connections are definitely correct. I
haven't checked voltages at the various voltage access points on the
board, but at this point I'm thinking that isn't necessary.

Incidentally, I do seem to be experiencing random USB disconnects as
described in 14.0 of the manual. I'll try the fix suggested there.
USB usually lasts only a couple of minutes before it disappears.

> (7) Has the board ever worked for you? You seem to say it works on OTG, but
> it is not clear. It sounds like it boots from a powerd HUB. If the HUB is
> not powered, then it must be plugged into a PC or there is no power. Some
> PCs cannot deliver the full power requiremnts even though they should.

The board has always worked if it's powered via a powered USB hub that
is plugged in to a host. If the hub is just powered, (or if I use a
USB cable with pins 2+3 removed) I get no console.

Thanks again.

[Gerald Coley]

See below.

 

Gerald

On Thu, Jul 8, 2010 at 1:56 AM, Paul Chvostek <paul+beagleboard.org@it.ca> wrote:

On Jul 7, 10:03 pm, Gerald Coley <ger...@beagleboard.org> wrote:
> I think you need to take it a step at a time. Please provide answers for
> each question. Just work with the 5V DC supply in this arrangement to remove
> one whole set of variables.
>
> (1) If the LEDs are correct, then you are booting.

Okay, my bad.  I had assumed that if I wasn't seeing any serial
console traffic, then the unit was not booting.  I bought an HDMI
cable today and connected a monitor to the board, powered up with a 5
V adapter, and lo and behold, I saw U-boot and kernel boot messages,
and eventually an Angstrom login prompt came up on the (HDMI) screen.
I then plugged in a USB Ethernet interface and rebooted, and was able
to SSH in.

So ... I see U-boot on the serial console if a monitor is plugged in
to HDMI *or* if the OTG is plugged in to a host.

 

No, you do not need a display plugged into the DVI-D port  to boot. You still should see messages on ther serial port if it is configured correctly. You do not need th eOTG hooked up to anything in order to boot, unless you are using ther OTG port to provide the power.

Very sorry I didn't think to investigate with an HDMI monitor before;
it didn't occur to me that lack of serial console output could mean
anything other than the unit not working.

But I'll answer a couple of the still-relevant points for good
measure...

> (2) I suggest you read Section 13 of the System Reference Manual and make
> sure that you have the correct serial cable connections and that everything
> is inserted corectly, ribbon cable not installed backwards. Does this all
> check out OK?

My serial cable and other connections are definitely correct.  I
haven't checked voltages at the various voltage access points on the
board, but at this point I'm thinking that isn't necessary.

Agreed from a boot standpoint, but you still should have boot messages sent to the serial port. So somehting is not correct.

 

Incidentally, I do seem to be experiencing random USB disconnects as
described in 14.0 of the manual.  I'll try the fix suggested there.
USB usually lasts only a couple of minutes before it disappears.

 

I would suggest that as well.

> (7) Has the board ever worked for you? You seem to say it works on OTG, but
> it is not clear. It sounds like it boots from a powerd HUB. If the HUB is
> not powered, then it must be plugged into a PC or there is no power.  Some
> PCs cannot deliver the full power requiremnts even though they should.

The board has always worked if it's powered via a powered USB hub that
is plugged in to a host.  If the hub is just powered, (or if I use a
USB cable with pins 2+3 removed) I get no console.

 

It sounds like the board is hanging looking for a USB boot source, where the code is loaded via the OTG port.

Thanks again.

[Koen Kooi]

Op 8 jul 2010, om 08:56 heeft Paul Chvostek het volgende geschreven:

>
> On Jul 7, 10:03 pm, Gerald Coley <ger...@beagleboard.org> wrote:
>> I think you need to take it a step at a time. Please provide answers for
>> each question. Just work with the 5V DC supply in this arrangement to remove
>> one whole set of variables.
>>
>> (1) If the LEDs are correct, then you are booting.
>
> Okay, my bad. I had assumed that if I wasn't seeing any serial
> console traffic, then the unit was not booting. I bought an HDMI
> cable today and connected a monitor to the board, powered up with a 5
> V adapter, and lo and behold, I saw U-boot and kernel boot messages,
> and eventually an Angstrom login prompt came up on the (HDMI) screen.
> I then plugged in a USB Ethernet interface and rebooted, and was able
> to SSH in.
>
> So ... I see U-boot on the serial console if a monitor is plugged in
> to HDMI *or* if the OTG is plugged in to a host.

Sounds like a grounding problem, are the groundwires loose in your usb cable?

regards,

Koen