Using mikroBUS¶
Steps:
Identify if mikroBUS add-on includes a ClickID with
manifest. If not,manifestmust 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
Using boards with ClickID¶
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 Using boards with Linux drivers.
Note
Not all Click boards with ClickID have valid manifest entries.
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.
First, make sure you have the latest manifests installed in your system.
sudo apt update
sudo apt install bbb.io-clickid-manifests
Take a look at the list of manifest files to see if the Click or other mikrobus add-on board manifest is installed.
debian@BeaglePlay:~$ ls /lib/firmware/mikrobus/
10DOF-CLICK.mnfb COMPASS-2-CLICK.mnfb I2C-2-SPI-CLICK.mnfb PWM-CLICK.mnfb
13DOF-2-CLICK.mnfb COMPASS-CLICK.mnfb I2C-MUX-CLICK.mnfb RFID-CLICK.mnfb
3D-HALL-3-CLICK.mnfb CURRENT-CLICK.mnfb ILLUMINANCE-CLICK.mnfb RF-METER-CLICK.mnfb
3D-HALL-6-CLICK.mnfb DAC-7-CLICK.mnfb IR-GESTURE-CLICK.mnfb RMS-TO-DC-CLICK.mnfb
6DOF-IMU-2-CLICK.mnfb DAC-CLICK.mnfb IR-THERMO-2-CLICK.mnfb RTC-6-CLICK.mnfb
6DOF-IMU-4-CLICK.mnfb DIGIPOT-3-CLICK.mnfb LED-DRIVER-7-CLICK.mnfb SHT1x-CLICK.mnfb
6DOF-IMU-6-CLICK.mnfb DIGIPOT-CLICK.mnfb LIGHTRANGER-2-CLICK.mnfb SHT-CLICK.mnfb
6DOF-IMU-8-CLICK.mnfb EEPROM-2-CLICK.mnfb LIGHTRANGER-3-CLICK.mnfb SMOKE-CLICK.mnfb
9DOF-CLICK.mnfb EEPROM-3-CLICK.mnfb LIGHTRANGER-CLICK.mnfb TEMP-HUM-11-CLICK.mnfb
ACCEL-3-CLICK.mnfb EEPROM-CLICK.mnfb LPS22HB-CLICK.mnfb TEMP-HUM-12-CLICK.mnfb
ACCEL-5-CLICK.mnfb ENVIRONMENT-CLICK.mnfb LSM303AGR-CLICK.mnfb TEMP-HUM-3-CLICK.mnfb
ACCEL-6-CLICK.mnfb ETH-CLICK.mnfb LSM6DSL-CLICK.mnfb TEMP-HUM-4-CLICK.mnfb
ACCEL-8-CLICK.mnfb ETH-WIZ-CLICK.mnfb MAGNETIC-LINEAR-CLICK.mnfb TEMP-HUM-7-CLICK.mnfb
ACCEL-CLICK.mnfb FLASH-2-CLICK.mnfb MAGNETIC-ROTARY-CLICK.mnfb TEMP-HUM-9-CLICK.mnfb
ADC-2-CLICK.mnfb FLASH-CLICK.mnfb MICROSD-CLICK.mnfb TEMP-HUM-CLICK.mnfb
ADC-3-CLICK.mnfb GENERIC-SPI-CLICK.mnfb MPU-9DOF-CLICK.mnfb TEMP-LOG-3-CLICK.mnfb
ADC-5-CLICK.mnfb GEOMAGNETIC-CLICK.mnfb MPU-IMU-CLICK.mnfb TEMP-LOG-4-CLICK.mnfb
ADC-8-CLICK.mnfb GNSS-4-CLICK.mnfb NO2-2-CLICK.mnfb TEMP-LOG-6-CLICK.mnfb
ADC-CLICK.mnfb GNSS-7-CLICK.mnfb NO2-CLICK.mnfb THERMO-12-CLICK.mnfb
AIR-QUALITY-2-CLICK.mnfb GNSS-ZOE-CLICK.mnfb OLEDB-CLICK.mnfb THERMO-15-CLICK.mnfb
AIR-QUALITY-3-CLICK.mnfb GSR-CLICK.mnfb OLEDC-CLICK.mnfb THERMO-17-CLICK.mnfb
AIR-QUALITY-5-CLICK.mnfb GYRO-2-CLICK.mnfb OLEDW-CLICK.mnfb THERMO-3-CLICK.mnfb
ALCOHOL-2-CLICK.mnfb GYRO-CLICK.mnfb OZONE-2-CLICK.mnfb THERMO-4-CLICK.mnfb
ALCOHOL-3-CLICK.mnfb HALL-CURRENT-2-CLICK.mnfb PRESSURE-11-CLICK.mnfb THERMO-7-CLICK.mnfb
ALTITUDE-3-CLICK.mnfb HALL-CURRENT-3-CLICK.mnfb PRESSURE-3-CLICK.mnfb THERMO-8-CLICK.mnfb
ALTITUDE-CLICK.mnfb HALL-CURRENT-4-CLICK.mnfb PRESSURE-4-CLICK.mnfb THERMO-CLICK.mnfb
AMBIENT-2-CLICK.mnfb HDC1000-CLICK.mnfb PRESSURE-CLICK.mnfb THERMOSTAT-3-CLICK.mnfb
AMBIENT-4-CLICK.mnfb HEART-RATE-3-CLICK.mnfb PROXIMITY-10-CLICK.mnfb UV-3-CLICK.mnfb
AMBIENT-5-CLICK.mnfb HEART-RATE-4-CLICK.mnfb PROXIMITY-2-CLICK.mnfb VACUUM-CLICK.mnfb
AMMETER-CLICK.mnfb HEART-RATE-5-CLICK.mnfb PROXIMITY-5-CLICK.mnfb VOLTMETER-CLICK.mnfb
COLOR-2-CLICK.mnfb HEART-RATE-7-CLICK.mnfb PROXIMITY-9-CLICK.mnfb WAVEFORM-CLICK.mnfb
COLOR-7-CLICK.mnfb HEART-RATE-CLICK.mnfb PROXIMITY-CLICK.mnfb WEATHER-CLICK.mnfb
Then, load the appropriate manifest using the mikrobus bus driver. For example, with the Ambient 2 Click, you can write that manifest to the mikrobus-0 new_device entry.
cat /lib/firmware/mikrobus/AMBIENT-2-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, …
To use the add-on, see Using boards with Linux drivers.
Using boards with Linux drivers¶
Depending on the type of mikrobus add-on board, the Linux driver could be of various different types. For sensors, the most common is IIO driver.
IIO driver¶
Per https://docs.kernel.org/driver-api/iio/intro.html,
The main purpose of the Industrial I/O subsystem (IIO) is to provide support for devices that in some sense perform either analog-to-digital conversion (ADC) or digital-to-analog conversion (DAC) or both. The aim is to fill the gap between the somewhat similar hwmon and input subsystems. Hwmon is directed at low sample rate sensors used to monitor and control the system itself, like fan speed control or temperature measurement. Input is, as its name suggests, focused on human interaction input devices (keyboard, mouse, touchscreen). In some cases there is considerable overlap between these and IIO.
Devices that fall into this category include:
analog to digital converters (ADCs)
accelerometers
capacitance to digital converters (CDCs)
digital to analog converters (DACs)
gyroscopes
inertial measurement units (IMUs)
color and light sensors
magnetometers
pressure sensors
proximity sensors
temperature sensors
See also https://wiki.analog.com/software/linux/docs/iio/iio.
To discover IIO driver enabled devices, use the iio_info command.
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
Note that the units are standardized for the IIO interface based on the device type. If raw values are provided, a scale must be applied to get to the standardized units.
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