shutdown procedure required for beaglebone black ??

[arunbarn...@gmail.com]

Hi,

I am trying to use the beaglebone black (in factory default settings) in a control application, where the BBB interfaces to a 20x4 character LCD, 18 button keypad, and a RS 232 connection using ttyO4 port (connects to RS 485 network using appropriate drivers).

I have almost developed the hardware and the software using Eclispe C++ IDE. 

As I am not using any batteries or other power backup devices for the BBB, Do I have to implement a shutdown procedure for my users ?? 

I have made a procedure in which the user presses a combination of keys to get the shutdown option on the LCD, selecting the shutdown option runs the system("shutdown -h now") command in my C++ program.

Is a shutdown procedure required for the BBB or will just pulling out the +5V power jack be sufficient. 

I have read in some sites that the eMMC could get corrupted causing startup issues....

Please advise....

thanks

a

[Gerald Coley]

Push the power button momentarily.

Gerald

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[arunbarn...@gmail.com]

So pulling out the power with properly shutting down the system could corrupt the eMMC ???

[Gerald Coley]

Nope. If you do it the way I just said, the board is powered off after it is done. Then you can pull the power. 

Pull the power without letting the kernel unmount the eMMC or SD card, and you can get corruption.

Gerald

[arunbarn...@gmail.com]

thanks that was very helpful..

[lmje...@gmail.com]

Hi Gerald,

Following the instructions on the BeagleBoard.org - getting-started webpage, my team lead and I have been powering up the BBB by using the provided USB cable to plug our Beagle into our computers.  We didn't find instructions on powering it down.  So, we have been powering it down by simply pulling the cable out.  By doing this, can we also get corruption?  If so, where is the shutdown procedure documented?

Lawrence

[Gerald Coley]

By doing this you can get corruption. Linux requires that you unmount the drives before powering down.

There is also a Linux shutdown command that can be used.

Gerald

For more options, visit https://groups.google.com/d/optout.

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Gerald

 

ger...@beagleboard.org

http://beagleboard.org/

[Chad Baker]

Section 5.10 in the SRM Rev C.1 recommends using the power button to power down the board and prevent contamination of the SD card or the eMMC. This section gives a brief explanation of why also.
Chad

For more options, visit https://groups.google.com/d/optout.

--
Chad Baker Memphis, TN

[Gerald Coley]

Assuming that the SW supports the power button function.

Gerald

Gerald

 

ger...@beagleboard.org

http://beagleboard.org/

[lmje...@gmail.com]

Hi Chad,

Thank you for pointing us to that section.  We missed seeing the recommendation, because it was somewhat implied.  We were searching for an instruction like "To power down the board, do ..."

Lawrence

[lmje...@gmail.com]

Hi Gerald,

Do you mean that the power button function may not necessary work?  Is the SW that supports it SW that I will need to develop, like the C++ SW that Arunbarn...@gmail.com was developing?

Lawrence

[lmje...@gmail.com]

Hi Gerald,

So to unmount the drives and power down the BBB, I can either push the power button momentarily or use the Linux shutdown command?

Lawrence

[lmje...@gmail.com]

Hi Gerald,

Please let us know we can unmount the drives and power down the BBB by either pushing the power button momentarily or using the Linux shutdown command.  We are refraining from powering up the BBB until we know how to power down the board correctly.

Lawrence

[lmje...@gmail.com]

Hi Gerald,

Oops, by "may not necessary work", I mean, "may not necessarily work."  Will I need to develop SW that supports the power button function - that is, will I need to develop SW to enable the button?  We are refraining from powering up the BBB until we know for sure.

Best regards,

Lawrence

[Gerald Coley]

It is a standard linux command to mount the drive.

Gerald

[lmje...@gmail.com]

Hi Gerald,

Do you mean the Linux umount command to un-mount the drive(s)?  In an earlier post, you said, "Assuming that the SW supports the power button function."  Were you saying that the umount command is assumed to support the function of the power button?

Lawrence

[Robert Nelson]

On Sat, Aug 22, 2015 at 12:50 AM, <lmje...@gmail.com> wrote:
> Hi Gerald,
>

> Do you mean the Linux umount command to un-mount the drive(s)? In an
> earlier post, you said, "Assuming that the SW supports the power button
> function." Were you saying that the umount command is assumed to support
> the function of the power button?
>
> Lawrence

Lawrence, are you a troll or lawyer? Based on how you question every email...

With the "current" images..

Push button -> signal to systemd -> systemd starts standard shutdown...

If your "image" doesn't do that, it's not "current"...

Regards,

--
Robert Nelson
https://rcn-ee.com/

[lmje...@gmail.com]

Hi Robert,

My apologies to you and the Forum for how I question every e-mail, but no, I'm neither a troll nor a lawyer.  I'm actually a software engineer with a physics background.

Thank you for showing me the chain of events that occur when the power button is pushed.  I now understand what Gerald meant: systemd was the SW he was referring to, and depending on the image, the SW might not support this chain.  According to the cat /etc/dogtag command, our image is

BeagleBoard.org BeagleBone Debian Image 2014-04-23

And according to the SparkFun Electronics website where my team HW lead bought our BBB, the rev is

Rev C - DEV-12857

Since the Beagleboard:BeagleBoneBlack - eLinux.org wikipage says the power button was added in Rev A6A, then our BBB should be able to execute the chain.  I tried it, and it works.  I also ran the shutdown command (actually, shutdown -h now, based on what I read in the other Forum topics), and it worked.  The wikipage also recommends issuing the halt command to power off the board; I tried that, too, and it also worked.  I have instructed my teammates to use the halt command, as it entails less typing and avoids the problem of fat fingers pushing the wrong component on the board.  However, not fifteen minutes after I told the HW lead, he unceremoniously pulled the USB cable out without issuing the halt command.  Sigh...

In any case, we now know the required shutdown procedure for the BBB.  Thank you, Robert, Gerald, and cmbaker3, for your assistance.  We really appreciate it.

Best regards,
Lawrence

[l...@pinkfroot.com]

I have an Element14 BBB running 4.1.10-ti-r22 Kernel and Debian 8.1 Jessie.

A momentary press of the PWR button does not have any effect and the manual suggests it should start a shut down command.

Holding it down for >8 seconds causes it to reset like the reset button so I know the hardware button is physically ok.

Lee

[woody stanford]

[quote]

Push the power button momentarily.

Gerald

[quote]

ROTFLMAO. Oh gawd that's the funniest thing I've read today. lmao *double thumbs up*

[tomle...@gmail.com]

Can you use a remote bottom. Does this start-stop bottom come out on the terminal strip?