Disable Display Cape and use HDMI

[Marco Liess]

Hi Guys, 

my problem is that I need to "switch" between using the display cape and the HDMI output of my BeagleBone Black Rev C. I can't always detach the Display Cape when I want to use HDMI because I plan on fitting my BBB in a permanent case. 

Is there a possibility to use the HDMI output when the Display Cape is attached to the Board? I can't seem to find an answer in any other questions or forums so I would really appreciate some help.

I'm currently using debian 9.5 with following kernel: 4.14.49-ti-r54

I've tried editing the /boot/uEnv.txt file to disable loading the Cape, but I've always come up with an error.

When I disable uboot_overlays and power up my BBB, the user LEDs start blinking but after a few seconds only the heartbeat LED is on, while the other LEDs are off permanently. On the screen I can only see the startup "penguin icon" but it's like the BBB froze. 

I've also tried uncommenting disable_uboot_overlay_addr0= and enabling uboot_overlays but then the same thing happens to the LEDs while my monitor doesn't even recognize a HDMI device. 

I am really stuck because I think it has to be possible to disable the Display Cape but I can't figure out how. Thank you in advance.

Regards 

Marco 

P.S: further information about my BBB

output of version.sh:

debian@beaglebone:~$ sudo /opt/scripts/tools/version.sh

git:/opt/scripts/:[31292bce1d4b35b497cc7a013d6d57e7e1f4f5c4]

eeprom:[A335BNLT00C01718BBBK072B]

model:[TI_AM335x_BeagleBone_Black]

dogtag:[BeagleBoard.org Debian Image 2018-06-17]

bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot 2018.03-00002-gac9cce7c6a]:[location: dd MBR]

kernel:[4.14.49-ti-r54]

nodejs:[v6.14.4]

uboot_overlay_options:[enable_uboot_overlays=1]

uboot_overlay_options:[uboot_overlay_addr6=/lib/firmware/BB-SPIDEV0-00A0.dtbo]

uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo]

uboot_overlay_options:[enable_uboot_cape_universal=1]

pkg check: to individually upgrade run: [sudo apt install --only-upgrade <pkg>]

pkg:[bb-cape-overlays]:[4.4.20180914.0-0rcnee0~stretch+20180914]

pkg:[bb-wl18xx-firmware]:[1.20180517-0rcnee0~stretch+20180517]

pkg:[kmod]:[23-2rcnee1~stretch+20171005]

pkg:[roboticscape]:[0.4.4-git20180608.0-0rcnee0~stretch+20180609]

pkg:[firmware-ti-connectivity]:[20170823-1rcnee1~stretch+20180328]

groups:[debian : debian adm kmem dialout cdrom floppy audio dip video plugdev users systemd-journal i2c bluetooth netdev cloud9ide gpio pwm eqep admin spi tisdk weston-launch xenomai]

cmdline:[console=ttyO0,115200n8 bone_capemgr.uboot_capemgr_enabled=1 root=/dev/mmcblk0p1 ro rootfstype=ext4 rootwait coherent_pool=1M net.ifnames=0 quiet]

dmesg | grep pinctrl-single

[    1.021968] pinctrl-single 44e10800.pinmux: 142 pins at pa f9e10800 size 568

dmesg | grep gpio-of-helper

[    1.023167] gpio-of-helper ocp:cape-universal: ready

END

[Robert Nelson]

On Mon, Sep 24, 2018 at 2:22 PM Marco Liess <mdl.m...@gmail.com> wrote:
>
> Hi Guys,
>
> my problem is that I need to "switch" between using the display cape and the HDMI output of my BeagleBone Black Rev C. I can't always detach the Display Cape when I want to use HDMI because I plan on fitting my BBB in a permanent case.
> Is there a possibility to use the HDMI output when the Display Cape is attached to the Board? I can't seem to find an answer in any other questions or forums so I would really appreciate some help.
>
> I'm currently using debian 9.5 with following kernel: 4.14.49-ti-r54
> I've tried editing the /boot/uEnv.txt file to disable loading the Cape, but I've always come up with an error.
> When I disable uboot_overlays and power up my BBB, the user LEDs start blinking but after a few seconds only the heartbeat LED is on, while the other LEDs are off permanently. On the screen I can only see the startup "penguin icon" but it's like the BBB froze.
> I've also tried uncommenting disable_uboot_overlay_addr0= and enabling uboot_overlays but then the same thing happens to the LEDs while my monitor doesn't even recognize a HDMI device.
>
> I am really stuck because I think it has to be possible to disable the Display Cape but I can't figure out how. Thank you in advance.

Currently, there's no way to disable "it"...

However you can "override it".... On startup, it'll pick addr0>3,
this is eaiser to figure out if you plug in a serial adapter. One
option is just to use:

uboot_overlay_addr0=/lib/firmware/BB-SPIDEV0-00A0.dtbo
uboot_overlay_addr1=/lib/firmware/BB-SPIDEV0-00A0.dtbo
uboot_overlay_addr2=/lib/firmware/BB-SPIDEV0-00A0.dtbo
uboot_overlay_addr3=/lib/firmware/BB-SPIDEV0-00A0.dtbo

Then it definitely won't load the display cape.

However this is definitely and odd one and one i didn't code for, so
i'm not sure if the hdmi will actually come up either...

Regards,

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

[Marco Liess]

Hi Robert,

Thank you very much for your quick response!

So I've tried overriding the cape with SPI and at first didn't have success. What did the job for me was looking for the "HDMI Cape" in /lib/firmware. So I edited my /boot/uEnv.txt to this:

uboot_oberlay_addr0=/lib/firmware/BB-HDMI-TDA998x-00A0.dtbo

uboot_oberlay_addr1=/lib/firmware/BB-SPIDEV0-00A0.dtbo

uboot_oberlay_addr2=/lib/firmware/BB-SPIDEV0-00A0.dtbo

uboot_oberlay_addr3=/lib/firmware/BB-SPIDEV0-00A0.dtbo

Now the Display is attached but I can use HDMI! :-) 

Thank you for your support. 

Regards

Marco