BBB LCD7 and 2013-06-20

Jetty · July 11, 2013, 7:03am

Regarding powersupply. Don’t trust the 5V / 2A label on a cheap USB hub type PSU. They might only give like 4.5V and the voltage might drop during load change (e.g when backlight turns on).

/Benny

I was originally using an adafruit 2A power supply for the BBB. However now I’m using a benchtop power supply, i.e. constant voltage and configurable current. I have it set to 3A and 5V. The 5V is maintained within 0.001V, and the current never approaches the maximum. So it’s not dropping power. The result is the same on either power supply.

Benny_Simonsen · July 11, 2013, 7:32am

Do you have the eMMC errors if you run dmesg?
If the system crashes before you can run dmesg when starting from eMMC then try to check dmesg while you are flashing the eMMC.

Jetty · July 11, 2013, 2:45pm

I get the eMMC errrors in the dmesg and a lot of them. You can see the errors I get in the 1st post in this thread.
Similar experience, sometimes boots, sometimes doesn’t, sometimes runs 5 mins then falls over. If I try to do anything, it crashes.

Jetty · July 12, 2013, 1:50am

Just an update on this, I received a reply today from BeagleBoardToys today, saying that they have replicated
the issue we’re having, and they are tracing the issue down and will have a response as soon as they find out.

genpix · July 13, 2013, 2:47am

thanks for update.
Similar to your case, I do trust my power supplies (I’m an electrical engineer after all, and do have a plenty of “electrical toys” here to fiddle with the power, including the power supplies of my own design).
In addition, (as I mentioned before) debian boots/works just fine with BBB + LCD7 on the very same power supplies which I tried with Angstrom image.

Micka · August 1, 2013, 9:05am

Did u got an update ?

Because, I’ve still this error :

tilcdc 4830e000.fb: timeout waiting for framedone

And just after that, the screen is shutting down !

Bas_Laarhoven1 · August 1, 2013, 9:28am

IIRC it's the screen shutting down that causes the message.

-- Bas

Micka · August 1, 2013, 9:31am

Ok, so why ?

Did someone get any update why the LCD is shutting down ?

Jetty, did u get any news from BeagleBoardToys ?

"Just an update on this, I received a reply today from BeagleBoardToys today, saying that they have replicated
the issue we’re having, and they are tracing the issue down and will have a response as soon as they find out."

Bas_Laarhoven1 · August 1, 2013, 9:43am

I'm not using the LCD7, but I'm getting these messages too.
Some kind of screen power down or sleep issue: If the power down is
called the interrupt does not fire (see tilcdc_crtc_dpms() in tilcdc_crtc.c).
Seems pretty harmless here. Maybe misconfiguration or a driver issue.

Is it fatal in your situation? (haven't followed this thread).

-- Bas

Micka · August 2, 2013, 12:07pm

Ok, next update,

I discovered that /sys/class/graphics/fb0/power/control was equal to “auto”

So I tried the command :

echo “on” > /sys/class/graphics/fb0/power/control

The command got recognized, but didn’t change any thing …

But, but I discovered something else :

http://www.armadeus.com/wiki/index.php?title=FrameBuffer

So it looks like there is a way to disable the sleep mode ? Yes

==>

To set “sleep mode”/screensaver entering time (where X is a time in minute; 0 = never):

 # echo -e '\033[9;X]' > /dev/tty1    (from serial console)

It looks like that in this example he is using this command on his computer that why he needed to transfer it to the serial console

But in my case, I’m connected by SSH, so i just need:

echo -e ‘\033[9;0]’

which work actually … finally I can disable the sleep mode !

Thx Bas Laarhoven, you helped me very well in my research !

Jetty · August 8, 2013, 3:01pm

Jetty, did u get any news from BeagleBoardToys ?

No, no update, and last time I asked for one, I got a terse reply saying they’re working on it.

Also noticed they haven’t updated: Beagleboard:BeagleBone Black Capes - eLinux.org
to say that LCD7 doesn’t work.

David_Anders · August 8, 2013, 5:10pm

Jetty,

just FYI, the LCD7 works with the black and the matrix is correct, however we have had an extremely small number of people who have reported issues with regards to the eMMC signal integrity which we are looking into.

one easy solution to test on your board is simply cut the pins for the eMMC signals on the LCD7 header. if indeed the eMMC signal integrity issue is what you are seeing, this will resolve the issue.

Dave Anders
Circuitco

Jetty · August 8, 2013, 6:02pm

Great to have an update. I’ve just tried this and it’s working so far.

But instead of making permanent changes to the LCD7 board / pins, I used some BB stacking headers from adafruit and just pulled pins 3-6 and 20-25 on P8 stacking header, and put the stacking headers between the BBB and the LCD7.

No eMMC errors so far.

Please let us know the mods we need to make to the board on this thread,
when you’ve ironed the eMMC issues and the fix.

Micka · August 8, 2013, 7:11pm

Hi Bas,

Just by curiousity, do you know a better way to disable the sleep mode of the screen ?

Because the only way that i know, is by using this command in a chron job:

echo 0 > /sys/class/graphics/fb0/blank

Bas_Laarhoven1 · August 8, 2013, 9:56pm

Hi Micka,

Sorry, the cronjob (workaround) was the only thing I could think of
and I haven't investigated further.
Maybe the people responsible for the product can help you.

-- Bas

Micka · August 9, 2013, 11:55am

Hi,

It looks like that when u run the xserver, the lcd don’t get anymore in sleep mode