avsa242 / lsm6dsl-spin

Parallax P8X32A/Propeller, P2X8C4M64P/Propeller 2 driver object for the ST LSM6DSL 6DoF IMU

lsm6dsl-spin

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This is a P8X32A/Propeller, P2X8C4M64P/Propeller 2 driver object for the ST LSM6DSL 6DoF IMU.

IMPORTANT: This software is meant to be used with the spin-standard-library (P8X32A) or p2-spin-standard-library (P2X8C4M64P). Please install the applicable library first before attempting to use this code, otherwise you will be missing several files required to build the project.

Salient Features

• SPI connection at 4MHz (P1), up to 10MHz (P2)
• Set accelerometer and gyroscope full-scale, data rate
• Read accelerometer raw data, or scaled to micro-G's (live or from FIFO)
• Read gyroscope raw data, or scaled to micro-dps (live or from FIFO)
• Data ready flags
• Manually or automatically set accel/gyro bias offsets (accel: on-chip, gyro: in MCU RAM)
• Soft-reset
• Gyroscope sleep mode
• Set gyroscope low-pass filter
• Set INT1 interrupt mask
• Click/tap-detection (single): set threshold, time, latency, per-axis detection
• Free-fall detection: set threshold, time
• Auto-sleep/wake/(in)activity detection
• FIFO functionality: empty, full, overrun, watermark flags, unread sample count, set decimation of data entries to FIFO, set mode, set data rate, set watermark level
• Pedometer (step counter) embedded functionality support

Requirements

P1/SPIN1:

• spin-standard-library
• 1 extra core/cog for the PASM I2C engine
• sensor.accel.common.spinh (provided by spin-standard-library)
• sensor.gyroscope.common.spinh (provided by spin-standard-library)

P2/SPIN2:

• p2-spin-standard-library
• sensor.accel.common.spinh (provided by spin-standard-library)
• sensor.gyroscope.common.spinh (provided by spin-standard-library)

Compiler Compatibility

Processor	Language	Compiler	Backend	Status
P1	SPIN1	FlexSpin (6.8.0)	Bytecode	OK
P1	SPIN1	FlexSpin (6.8.0)	Native/PASM	OK
P2	SPIN2	FlexSpin (6.8.0)	NuCode	Runtime issues
P2	SPIN2	FlexSpin (6.8.0)	Native/PASM2	OK

(other versions or toolchains not listed are not supported, and may or may not work)

Limitations

• Click detection currently only supports single-click

Known issues

• When gyro_scale() is set to 2000dps, it is technically possible (though unlikely in practice) for the measurements returned by gyro_dps() to overflow 32-bit signed integer max - this isn't protected against

lsm6dsl-spin's Issues

CalibrateGyro() gives poor results

Setting Gyroscope bias offsets with CalibrateGyro() gives poor results as compared to manually entered values from trial and error.

Add FIFO support

The chip has a FIFO memory that isn't yet implemented - currently the methods are only defined as placeholders, with no actual code.

Overflow possible in GyroDPS() when scale is 2000dps

When GyroScale() is set to 2000dps, it is possible for the measurements returned by GyroDPS() to overflow spin's long/32-bit signed integer - this isn't protected.

Calibration results poor

Gyro results seem to vary wildly, and are several whole degrees off 0.
The accelerometer Z-axis isn't horrible, but could be better.
Both processors P1, P2, and both interfaces I2C, SPI seem equally affected.

Add free-fall detection

Add support for the chip's ability to detect free-falls.

Add support for wake-on-motion

Add support for the chip's wake from a low-power state function.

Add step-detection/counting support

The chip could be used to create a pedometer.

Scaling incorrect for gyro 125dps range

The gyroscope scaling factor is off by a factor of 10 for the 125dps range - should be 4_375 (4.375 * 1000).