dtbo for mikrobus cape

General Discussion
1

I have a MikroBus cape by Tigal, I think identical to the one discussed here: Add DTS for MikroBus Cape for BBB and yes, it’s that old.

I’m trying to get the dts into this decade. It seems to get loaded, as the symlinks I put in for the UARTs are created, but I must be doing someting wrong, because the symlinks for the SPI interfaces are not there. Now, this is a process of educated guesses more than targeted development, so making mistakes is quite likely, but a hint is appreciated.

BB-MIKROBUS-01-00A1 (v2).dts (8.1 KB)

Beagle-version:

root@BeagleBone:~# beagle-version 
eeprom:[A335BNLT00C04414BBBK1595]
model:[TI_AM335x_BeagleBone_Black]
dogtag:[BeagleBoard.org Debian Trixie Base Image 2026-05-19]
bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot SPL 2022.04-g5509547b (Jan 22 2026 - 19:56:08 +0000)]:[location: dd MBR]
UBOOT: Booted Device-Tree:[am335x-boneblack-uboot.dts]
UBOOT: Loaded Overlay:[BB-ADC-00A0.kernel]
UBOOT: Loaded Overlay:[BB-BONE-eMMC1-01-00A0.kernel]
kernel:[6.18.32-bone35]
/boot/uEnv.txt Settings:
uboot_overlay_options:[enable_uboot_overlays=1]
uboot_overlay_options:[disable_uboot_overlay_video=1]
uboot_overlay_options:[uboot_overlay_pru=AM335X-PRU-UIO-00A0.dtbo]
uboot_overlay_options:[enable_uboot_cape_universal=1]
pkg check: to individually upgrade run: [sudo apt install --only-upgrade <pkg>]
pkg:[bb-customizations]:[1.20250808.0-0~trixie+20250808]
pkg:[bb-usb-gadgets]:[1.20260427.1-0~trixie+20260427]
pkg:[bb-wl18xx-firmware]:[1.20230703.0-0~trixie+20240703]
pkg:[kmod]:[34.2-2bbbio1~trixie+20250522]
groups:[remco : remco adm kmem dialout cdrom floppy audio dip video plugdev users systemd-journal input render netdev i2c bluetooth gpio admin tisdk weston-launch]
cmdline:[console=ttyS0,115200n8 root=/dev/mmcblk1p3 ro rootfstype=ext4 rootwait uboot_detected_capes=BB-MIKROBUS-01, fsck.repair=yes earlycon coherent_pool=1M net.ifnames=0 lpj=1990656 rng_core.default_quality=100]
dmesg | grep remote
[    3.597716] remoteproc remoteproc0: wkup_m3 is available
[    6.002589] remoteproc remoteproc0: powering up wkup_m3
[    6.036985] remoteproc remoteproc0: Booting fw image am335x-pm-firmware.elf, size 217148
[    6.093495] remoteproc remoteproc0: remote processor wkup_m3 is now up
[   17.098163] systemd[1]: Reached target remote-fs.target - Remote File Systems.
[   55.362555] remoteproc remoteproc1: 4a334000.pru is available
[   55.381775] remoteproc remoteproc2: 4a338000.pru is available
dmesg | grep pru
[   55.362555] remoteproc remoteproc1: 4a334000.pru is available
[   55.381775] remoteproc remoteproc2: 4a338000.pru is available
dmesg | grep pinctrl-single
[    3.618832] pinctrl-single 44e10800.pinmux: 142 pins, size 568
dmesg | grep gpio-of-helper
dmesg | grep wlcore
lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
END

What I find surprising is that ‘UBOOT: Loaded Overlay:’ doesn’t mention the overlay, but it is clearly doing something, maybe that is because of the eprom, and this cape is properly detected?

2

Yeah, good question, no error reporting. The overlay appears to load but nothing, right? Join the club, you can find many threads dealing with this issue.

Seem the legacy device tree overlays don’t work with the new kernels. You may need to re-write the overlay.

Has anyone found the documentation for these needed device tree overlay changes?

Check out this thread.
https://forum.beagleboard.org/t/problem-setting-pin-modes-and-configurations-using-a-device-tree-overlay

3

Hi,

I found a great resource: GitHub - beagleboard/bb.org-overlays: Replaced by: https://github.com/beagleboard/BeagleBoard-DeviceTrees · GitHub Now, this is not sacret as building a dts from scratch or even these samples is still more guesswork than I’m used to (usually I have at least some understanding of the language I’m using), but since there are the 4 mikrobus cape dts files like this one: bb.org-overlays/src/arm/BB-MIKROBUS-CAPE-1.dts at master · beagleboard/bb.org-overlays · GitHub that I can use for inspiration and I have the original as well. I think it’s really cool that Robert has bothered to compile this repository and I’m hoping to be able to combine these 4 into a single file. I know I probably don’t have to, I could just load the 4 separate files, but having a single overlay file would be cool.

It’s been quite a while since I even looked at my BBB, but I have good confidence that I can bring it up to date with some help.

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