ADIS16480 driver

This driver supports Analog Device’s IMUs on SPI bus.

1. Supported devices

• ADIS16375

• ADIS16480

• ADIS16485

• ADIS16488

• ADIS16490

• ADIS16495

• ADIS16497

• ADIS16545

• ADIS16547

Each supported device is a complete inertial system that includes a triaxial gyroscope and a triaxial accelerometer. Each inertial sensor in device combines with signal conditioning that optimizes dynamic performance. The factory calibration characterizes each sensor for sensitivity, bias, and alignment. As a result, each sensor has its own dynamic compensation formulas that provide accurate sensor measurements.

2. Device attributes

Accelerometer, gyroscope measurements are always provided. Furthermore, the driver offers the capability to retrieve the delta angle and the delta velocity measurements computed by the device.

The delta angle measurements represent a calculation of angular displacement between each sample update, while the delta velocity measurements represent a calculation of linear velocity change between each sample update.

Finally, temperature data are provided which show a coarse measurement of the temperature inside of the IMU device. This data is most useful for monitoring relative changes in the thermal environment.

ADIS16480 and ADIS16488 also provide access to barometric pressure data and triaxial magnetometer measurements.

Each IIO device, has a device folder under /sys/bus/iio/devices/iio:deviceX, where X is the IIO index of the device. Under these folders reside a set of device files, depending on the characteristics and features of the hardware device in questions. These files are consistently generalized and documented in the IIO ABI documentation.

The following tables show the adis16480 related device files, found in the specific device folder path /sys/bus/iio/devices/iio:deviceX.

Available only for ADIS16480 and ADIS16488:

3-Axis Magnetometer related device files	Description
in_magn_scale	Scale for the magnetometer channels.
in_magn_x_calibbias	Calibration offset for the X-axis magnetometer channel.
in_magn_x_filter_low_pass_3db_frequency	Bandwidth for the X-axis magnetometer channel.
in_magn_x_raw	Raw X-axis magnetometer channel value.
in_magn_y_calibbias	Calibration offset for the Y-axis magnetometer channel.
in_magn_y_filter_low_pass_3db_frequency	Bandwidth for the Y-axis magnetometer channel.
in_magn_y_raw	Raw Y-axis magnetometer channel value.
in_magn_z_calibbias	Calibration offset for the Z-axis magnetometer channel.
in_magn_z_filter_low_pass_3db_frequency	Bandwidth for the Z-axis magnetometer channel.
in_magn_z_raw	Raw Z-axis magnetometer channel value.

Barometric pressure sensor related files	Description
in_pressure0_calibbias	Calibration offset for barometric pressure channel.
in_pressure0_raw	Raw barometric pressure channel value.
in_pressure0_scale	Scale for the barometric pressure sensor channel.

Available for all supported devices:

3-Axis Accelerometer related device files	Description
in_accel_scale	Scale for the accelerometer channels.
in_accel_x_calibbias	Calibration offset for the X-axis accelerometer channel.
in_accel_x_calibscale	Calibration scale for the X-axis accelerometer channel.
in_accel_x_filter_low_pass_3db_frequency	Bandwidth for the X-axis accelerometer channel.
in_accel_x_raw	Raw X-axis accelerometer channel value.
in_accel_y_calibbias	Calibration offset for the Y-axis accelerometer channel.
in_accel_y_calibscale	Calibration scale for the Y-axis accelerometer channel.
in_accel_y_filter_low_pass_3db_frequency	Bandwidth for the Y-axis accelerometer channel.
in_accel_y_raw	Raw Y-axis accelerometer channel value.
in_accel_z_calibbias	Calibration offset for the Z-axis accelerometer channel.
in_accel_z_calibscale	Calibration scale for the Z-axis accelerometer channel.
in_accel_z_filter_low_pass_3db_frequency	Bandwidth for the Z-axis accelerometer channel.
in_accel_z_raw	Raw Z-axis accelerometer channel value.
in_deltavelocity_scale	Scale for delta velocity channels.
in_deltavelocity_x_raw	Raw X-axis delta velocity channel value.
in_deltavelocity_y_raw	Raw Y-axis delta velocity channel value.
in_deltavelocity_z_raw	Raw Z-axis delta velocity channel value.

3-Axis Gyroscope related device files	Description
in_anglvel_scale	Scale for the gyroscope channels.
in_anglvel_x_calibbias	Calibration offset for the X-axis gyroscope channel.
in_anglvel_x_calibscale	Calibration scale for the X-axis gyroscope channel.
in_anglvel_x_filter_low_pass_3db_frequency	Bandwidth for the X-axis gyroscope channel.
in_anglvel_x_raw	Raw X-axis gyroscope channel value.
in_anglvel_y_calibbias	Calibration offset for the Y-axis gyroscope channel.
in_anglvel_y_calibscale	Calibration scale for the Y-axis gyroscope channel.
in_anglvel_y_filter_low_pass_3db_frequency	Bandwidth for the Y-axis gyroscope channel.
in_anglvel_y_raw	Raw Y-axis gyroscope channel value.
in_anglvel_z_calibbias	Calibration offset for the Z-axis gyroscope channel.
in_anglvel_z_calibscale	Calibration scale for the Z-axis gyroscope channel.
in_anglvel_z_filter_low_pass_3db_frequency	Bandwidth for the Z-axis gyroscope channel.
in_anglvel_z_raw	Raw Z-axis gyroscope channel value.
in_deltaangl_scale	Scale for delta angle channels.
in_deltaangl_x_raw	Raw X-axis delta angle channel value.
in_deltaangl_y_raw	Raw Y-axis delta angle channel value.
in_deltaangl_z_raw	Raw Z-axis delta angle channel value.

Temperature sensor related files	Description
in_temp0_raw	Raw temperature channel value.
in_temp0_offset	Offset for the temperature sensor channel.
in_temp0_scale	Scale for the temperature sensor channel.

Miscellaneous device files	Description
name	Name of the IIO device.
sampling_frequency	Currently selected sample rate.

The following table shows the adis16480 related device debug files, found in the specific device debug folder path /sys/kernel/debug/iio/iio:deviceX.

Debugfs device files	Description
serial_number	The serial number of the chip in hexadecimal format.
product_id	Chip specific product id (e.g. 16480, 16488, 16545, etc.).
flash_count	The number of flash writes performed on the device.
firmware_revision	String containing the firmware revision in the following format ##.##.
firmware_date	String containing the firmware date in the following format mm-dd-yyyy.

Channels processed values

A channel value can be read from its _raw attribute. The value returned is the raw value as reported by the devices. To get the processed value of the channel, apply the following formula:

processed value = (_raw + _offset) * _scale

Where _offset and _scale are device attributes. If no _offset attribute is present, simply assume its value is 0.

The adis16480 driver offers data for 7 types of channels, the table below shows the measurement units for the processed value, which are defined by the IIO framework:

Channel type	Measurement unit
Acceleration on X, Y, and Z axis	Meters per Second squared
Angular velocity on X, Y and Z axis	Radians per second
Delta velocity on X. Y, and Z axis	Meters per Second
Delta angle on X, Y, and Z axis	Radians
Temperature	Millidegrees Celsius
Magnetic field along X, Y and Z axis	Gauss
Barometric pressure	kilo Pascal

Usage examples

Show device name:

root:/sys/bus/iio/devices/iio:device0> cat name
adis16545-1

Show accelerometer channels value:

root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw
1376728
root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw
4487621
root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw
262773792
root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale
0.000000037

• X-axis acceleration = in_accel_x_raw * in_accel_scale = 0.050938936 m/s^2

• Y-axis acceleration = in_accel_y_raw * in_accel_scale = 0.166041977 m/s^2

• Z-axis acceleration = in_accel_z_raw * in_accel_scale = 9.722630304 m/s^2

Show gyroscope channels value:

root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_x_raw
-1041702
root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_raw
-273013
root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_z_raw
2745116
root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_scale
0.000000001

• X-axis angular velocity = in_anglvel_x_raw * in_anglvel_scale = −0.001041702 rad/s

• Y-axis angular velocity = in_anglvel_y_raw * in_anglvel_scale = −0.000273013 rad/s

• Z-axis angular velocity = in_anglvel_z_raw * in_anglvel_scale = 0.002745116 rad/s

Set calibration offset for accelerometer channels:

root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias
0

root:/sys/bus/iio/devices/iio:device0> echo 5000 > in_accel_x_calibbias
root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias
5000

Set calibration offset for gyroscope channels:

root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias
0

root:/sys/bus/iio/devices/iio:device0> echo -5000 > in_anglvel_y_calibbias
root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias
-5000

Set sampling frequency:

root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency
4250.000000

root:/sys/bus/iio/devices/iio:device0> echo 1000 > sampling_frequency
1062.500000

Set bandwidth for accelerometer channels:

root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_filter_low_pass_3db_frequency
0

root:/sys/bus/iio/devices/iio:device0> echo 300 > in_accel_x_filter_low_pass_3db_frequency
root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_filter_low_pass_3db_frequency
300

Show serial number:

root:/sys/kernel/debug/iio/iio:device0> cat serial_number
0x000c

Show product id:

root:/sys/kernel/debug/iio/iio:device0> cat product_id
16545

Show flash count:

root:/sys/kernel/debug/iio/iio:device0> cat flash_count
88

Show firmware revision:

root:/sys/kernel/debug/iio/iio:device0> cat firmware_revision
1.4

Show firmware date:

root:/sys/kernel/debug/iio/iio:device0> cat firmware_date
09-23-2023

3. Device buffers

This driver supports IIO buffers.

All devices support retrieving the raw acceleration, gyroscope and temperature measurements using buffers.

The following device families also support retrieving the delta velocity, delta angle and temperature measurements using buffers:

• ADIS16545

• ADIS16547

However, when retrieving acceleration or gyroscope data using buffers, delta readings will not be available and vice versa. This is because the device only allows to read either acceleration and gyroscope data or delta velocity and delta angle data at a time and switching between these two burst data selection modes is time consuming.

Usage examples

Set device trigger in current_trigger, if not already set:

root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger

root:/sys/bus/iio/devices/iio:device0> echo adis16545-1-dev0 > trigger/current_trigger
root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger
adis16545-1-dev0

Select channels for buffer read:

root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_x_en
root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_y_en
root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_z_en
root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_temp0_en

Set the number of samples to be stored in the buffer:

root:/sys/bus/iio/devices/iio:device0> echo 10 > buffer/length

Enable buffer readings:

root:/sys/bus/iio/devices/iio:device0> echo 1 > buffer/enable

Obtain buffered data:

root:/sys/bus/iio/devices/iio:device0> hexdump -C /dev/iio\:device0
...
00006aa0  09 62 00 00 ff ff fc a4  00 00 01 69 00 03 3c 08  |.b.........i..<.|
00006ab0  09 61 00 00 00 00 02 96  00 00 02 8f 00 03 37 50  |.a............7P|
00006ac0  09 61 00 00 00 00 12 3d  00 00 0b 89 00 03 2c 0b  |.a.....=......,.|
00006ad0  09 61 00 00 00 00 1e dc  00 00 16 dd 00 03 25 bf  |.a............%.|
00006ae0  09 61 00 00 00 00 1e e3  00 00 1b bf 00 03 27 0b  |.a............'.|
00006af0  09 61 00 00 00 00 15 50  00 00 19 44 00 03 30 fd  |.a.....P...D..0.|
00006b00  09 61 00 00 00 00 09 0e  00 00 14 41 00 03 3d 7f  |.a.........A..=.|
00006b10  09 61 00 00 ff ff ff f0  00 00 0e bc 00 03 48 d0  |.a............H.|
00006b20  09 63 00 00 00 00 00 9f  00 00 0f 37 00 03 4c fe  |.c.........7..L.|
00006b30  09 64 00 00 00 00 0b f6  00 00 18 92 00 03 43 22  |.d............C"|
00006b40  09 64 00 00 00 00 18 df  00 00 22 33 00 03 33 ab  |.d........"3..3.|
00006b50  09 63 00 00 00 00 1e 81  00 00 26 be 00 03 29 60  |.c........&...)`|
00006b60  09 63 00 00 00 00 1b 13  00 00 22 2f 00 03 23 91  |.c........"/..#.|
...

See Documentation/iio/iio_devbuf.rst for more information about how buffered data is structured.

4. IIO Interfacing Tools

See Documentation/iio/iio_tools.rst for the description of the available IIO interfacing tools.