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CAPE- 4DCAPE-43T on Linux beaglebone 4.1.4-ti-r8 not working

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  • CAPE- 4DCAPE-43T on Linux beaglebone 4.1.4-ti-r8 not working

    The cape is recognized and in fact works under the Angstrom distribution and the Debian 3.8 but not under 4.1. The previous posting on this forum for this subject had a solution that doesn't appear to work with the standard distribution. I'm running a Rev B from the MicroSD card that boots automatically without holding down any switches. If I puTTY into it I can start the VNC server (or for that matter Windows Remote Desktop server) and work with it using TightVNC.

    I've written a Python program that uses a Tkinter Canvas set to 480x272 with gauges and indicators. One gauge object shows the temperature from a One-Wire interface DS1822. I'd like to be able to have the canvas fit onto the 4.3" display. Perhaps even add buttons etc.in the future.

    So first problem is that I don't see anything on the LCD other than the back light. Since 4D Systems is still selling this display and the Jesse version has been out for a few months there must be a simple solution?

    Thanks
    John



    [email protected]:~# cat $SLOTS
    0: P---L- 1 4D 4.3 LCD CAPE- 4DCAPE-43T ,00A1,4D SYSTEMS ,BB-BONE-LCD4-01
    1: PF---- -1
    2: PF---- -1
    3: PF---- -1
    4: P-O-L- 0 Override Board Name,00A0,Override Manuf,BB-W1-P8.11

    [email protected]:~# uname -a
    Linux beaglebone 4.1.4-ti-r8 #1 SMP PREEMPT Thu Aug 6 21:01:16 UTC 2015 armv7l GNU/Linux

    [email protected]:~# cat /etc/dogtag
    BeagleBoard.org Debian Image 2015-08-09

    [email protected]:~# lsb_release -a
    No LSB modules are available.
    Distributor ID: Debian
    Description: Debian GNU/Linux 8.6 (jessie)
    Release: 8.6
    Codename: jessie
    4.1.4-ti-r8
    [email protected]:~#


  • #2
    Hi John

    4D Doesn't make the software, so we have no control over this. Recently, for some reason, the distributions changed and their requirements are a little different compared to before.

    Talking to Robert Nelson, one of the main developers for the BBB Software releases, he said you now need to un-comment the overlay in the uEnv.txt file so the LCD capes work as expected.

    Edit the /boot/uEnv.txt, and uncomment the overlay:

    dtb=am335x-boneblack-overlay.dtb

    From memory this disables the HDMI and eMMC or something like that. Pretty sure it says in the comments in that file.

    Might want to use this release, compared to the one on the latest-images page, as that is a few months old.

    https://rcn-ee.net/rootfs/bb.org/tes...-27-4gb.img.xz

    Code:
    https://rcn-ee.net/rootfs/bb.org/testing/2016-11-27/lxqt-4gb/bone-debian-8.6-lxqt-4gb-armhf-2016-11-27-4gb.img.xz
    See if that helps you
    James

    Comment


    • Beuf
      Beuf commented
      Editing a comment
      Editing the /boot/uEnv.txt file worked for me. However the suggested line also disables the eMMC and only allows booting from SD card. Enabling (remove #) the following line disables HDMI (allowing the cape to work) while keeping eMMC functionality running:

      ##BeagleBone Black: HDMI (Audio/Video) disabled:
      dtb=am335x-boneblack-emmc-overlay.dtb

  • #3
    Hi James,
    Thanks. Unfortunately that didn't work. At least not right way with a
    shutdown -r now

    On a hunch I issued a
    shutdown -h now

    and then removed power rather than just pressing the power button.
    Now I have a working screen.

    Selecting the reboot option from the screen (with mouse connected to USB port) appears to shut down and restart. Eventually puTTY can connect but the display goes dark, and then lights up again with random garbage.

    I signed on with puTTY as root and issued a
    shutdown -r now
    and again I have a working screen.

    I then ran the shutdown command from the LCD display window (instead of reboot) and waited until the power went off. Then pressed the power button on the LCD Cape.
    And it's alive again.

    What doesn't show up after booting is the set of 4 points to calibrate the touch screen. So that's still different from my Angstrom start-up.

    I don't really want to update the image because then I'd lose the changes with the /etc/rc.local and my initrd which enabled my on-wire driver not to mention all the other software packages that have been installed now.

    A number of beagles will be headless while a number of others will all have the 4.3 display.

    I've attached both the /boot/uEnv.txt file along with /var/log/messages holding the last two boot sequences. From what I can see they are identical but perhaps I'm missing something.

    Something with the display initialization isn't quite right nor repeatable. Any suggestions there would be welcome.

    I've also attached a photo of the Python Tkinter program targeted for this display. I still need to remove the bottom tool bar but things are looking up.

    John
    Attached Files

    Comment

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