Using mikroBUS¶
Using boards with ClickID¶
Steps:
Identify if mikroBUS add-on includes an ID. If not, ID must be supplied.
Identify if mikroBUS add-on is supported by the kernel. If not, kernel module must be added.
Identify how driver exposes the data: IIO, net, etc.
Connect and power
Verify and utilize
What is mikroBUS?¶
mikroBUS is an open standard for add-on boards for sensors, connectivity, displays, storage and more with over 1,400 available from just a single source, MikroE. With the flexibility of all of the most common embedded serial busses, UART, I2C and SPI, along with ADC, PWM and GPIO functions, it is a great solution for connecting all sorts of electronics.
Note
Learn more at https://www.mikroe.com/mikrobus
What is ClickID?¶
ClickID enables mikroBUS add-on boards to be identified along with the configuration required to use it with the mikroBUS Linux driver. The configuration portion is called a manifest.
Note
Learn more at https://github.com/MikroElektronika/click_id
BeaglePlay’s Linux kernel is patched with a mikrobus driver that automatically reads the ClickID and loads a driver, greatly simplifying usage.
Does my add-on have ClickID?¶
Look for the “ID” logo on the board. It should be on the side with the pins sticking out, near the AN pin.
Todo
Need an image of the logo
If your add-on has ClickID, simply connect it while BeaglePlay is powered off and then apply power.
Example of examining boot log to see a ClickID was detected.
debian@BeaglePlay:~$ dmesg | grep mikrobus
[ 2.096254] mikrobus:mikrobus_port_register: registering port mikrobus-0
[ 2.096325] mikrobus mikrobus-0: mikrobus port 0 eeprom empty probing default eeprom
[ 2.663698] mikrobus_manifest:mikrobus_manifest_attach_device: parsed device 1, driver=opt3001, protocol=3, reg=44
[ 2.663711] mikrobus_manifest:mikrobus_manifest_parse: Ambient 2 Click manifest parsed with 1 devices
[ 2.663783] mikrobus mikrobus-0: registering device : opt3001
To use the add-on, see TBD below.
What if my add-on doesn’t have ClickID?¶
It is still possible a manifest has been created for your add-on as we have created over 100 of them. You can install the existing manifest files onto your BeaglePlay.
sudo apt update
sudo apt install bbb.io-clickid-manifests
cat /lib/firmware/mikrobus/amibient-light-click.mnfb > /sys/bus/mikrobus/devices/mikrobus-0/new_device
Note
We will be adding a link to the mikrobus-0 device at /dev/play/mikrobus in the near
future, but you can find it for now at /sys/bus/mikrobus/devices/mikrobus-0. If you
need to supply an ID (manifest), this is the directory where you will do it.
Manifesto: https://git.beagleboard.org/beagleconnect/manifesto
Patched Linux with out-of-tree Mikrobus driver: https://git.beagleboard.org/beagleboard/linux
Note
It’ll forget on reboot… need to have a boot service.
Todo
To make it stick, …
Using boards with Linux drivers¶
IIO driver¶
https://docs.kernel.org/driver-api/iio/intro.html
debian@BeaglePlay:~$ iio_info
Library version: 0.24 (git tag: v0.24)
Compiled with backends: local xml ip usb
IIO context created with local backend.
Backend version: 0.24 (git tag: v0.24)
Backend description string: Linux BeaglePlay 5.10.168-ti-arm64-r104 #1bullseye SMP Thu Jun 8 23:07:22 UTC 2023 aarch64
IIO context has 2 attributes:
local,kernel: 5.10.168-ti-arm64-r104
uri: local:
IIO context has 2 devices:
iio:device0: opt3001
1 channels found:
illuminance: (input)
2 channel-specific attributes found:
attr 0: input value: 163.680000
attr 1: integration_time value: 0.800000
2 device-specific attributes found:
attr 0: current_timestamp_clock value: realtime
attr 1: integration_time_available value: 0.1 0.8
No trigger on this device
iio:device1: adc102s051
2 channels found:
voltage1: (input)
2 channel-specific attributes found:
attr 0: raw value: 4084
attr 1: scale value: 0.805664062
voltage0: (input)
2 channel-specific attributes found:
attr 0: raw value: 2440
attr 1: scale value: 0.805664062
No trigger on this device
Storage driver¶
Network driver¶
How does ClickID work?¶
Disabling the mikroBUS driver¶
If you’d like to use other means to control the mikroBUS connector, you might want to disable the mikroBUS driver. This is most easily done by enabling a deivce tree overlay at boot.
Todo
Document kernel version that integrates this overlay and where to get update instructions.
Note
To utilize the overlay with these instructions, make sure to have TBD version of kernel, modules and firmware installed. Use uname -a to determine the currently running kernel version. See TBD for information on how to update.
Apply overlay to disable mikrobus0 instance.
echo " fdtoverlays /overlays/k3-am625-beagleplay-release-mikrobus.dtbo" | sudo tee -a /boot/firmware/extlinux/extlinux.conf
sudo shutdown -r now
Log back in after reboot and verify the device driver did not capture the busses.
debian@BeaglePlay:~$ ls /dev/play
grove mikrobus qwiic
debian@BeaglePlay:~$ ls /dev/play/mikrobus/
i2c
debian@BeaglePlay:~$ ls /sys/bus/mikrobus/devices/
debian@BeaglePlay:~$ ls /proc/device-tree/chosen/overlays/
k3-am625-beagleplay-release-mikrobus name
debian@BeaglePlay:~$
To re-enable.
sudo sed -e '/release-mikrobus/ s/^#*/#/' -i /boot/firmware/extlinux/extlinux.conf
sudo shutdown -r now
Verify driver is enabled again.
debian@BeaglePlay:~$ ls /sys/bus/mikrobus/devices/
mikrobus-0
debian@BeaglePlay:~$ ls /proc/device-tree/chosen/overlays/
ls: cannot access '/proc/device-tree/chosen/overlays/': No such file or directory
debian@BeaglePlay:~$
Todo
How do turn off the driver?
How do turn on spidev?
How do I enable GPIO?
How do a provide a manifest?
Todo
Needs udev
Needs live description