AS5601 Library for Arduino

A wrapper for driving the cheap but great magnetic rotary sensor AS5601 over I²C on an Arduino. The library aims to offer clean high-level access to the sensor's capabilities and to provide convenience functions for common tasks. The current implementation supports only a subset of the sensor's functionality, more functions may be added in future versions.

Quick Start

Initialize the driver, which sets up the I²C bus:

AS5601 Sensor;

Find out if the magnet is in range:

if ( Sensor.magnetDetected() ) { … }

Query the sensor to get the magnet's current angle:

int angle = Sensor.getAngle();

Reference

Static Properties

The sensor's register addresses are available as static constants as specified in the datasheet. The struct ByteRegister includes the 8-bit registers, WordRegister contains the starting addresses of the 16-bit registers.

Low-Level Instance Methods

readRaw8( registerAddress )

Reads 8 bits from a register at the specified address.
registerAddress unsigned char The address to read from. For example, AS5601::ByteRegister::STATUS.
Returns the read byte as unsigned char.

readRaw16( registerStartAddress )

Reads 16 bits from a register, starting at the specified address.
registerStartAddress unsigned char The address to begin reading from. For example, AS5601::WordRegister::ANGLE.
Returns the read word as unsigned int.

writeRaw8( registerAddress, value )

Writes 8 bits to a register at the specified address.
registerAddress unsigned char The address to write to. For example, AS5601::ByteRegister::ABN.

writeRaw16( registerStartAddress, value )

Writes 16 bits to a register, starting at the specified address.
registerAddress unsigned char The address to begin writing to. For example, AS5601::WordRegister::ZPOS.

Higher-Level Instance Methods

magnetDetected()

Queries the sensor's status register to find out whether a magnet's presence is detected.
Returns true or false as bool.

getMagnitude()

Reads the current magnetic magnitude measurement from the sensor.
Returns a 12-bit value as unsigned int.

getGain()

Reads the AGC's current gain setting from the sensor.
Returns an 8-bit value as unsigned char.

getRawAngle()

Reads the current raw angle estimation from the sensor.
Returns a 12-bit value as unsigned int.

setZeroPosition( rawAngle )

Sets the sensor's zero-compensation value to the specified angle.
rawAngle unsigned int An integer angle ∈ [0,4095] as returned by getRawAngle(). Can be omitted for convenience to use the sensor's current raw angle.

setResolution( angleSteps )

Configures the sensor's angle output resolution. (Note: This does not seem to change the values returned by getAngle() but probably affects the sensor's A/B output.)
angleSteps unsigned int An integer number of angle steps in a full circle. Supported values are 8, 16, 32, …, 2048.

getAngle()

Reads the filtered and zero-compensated angle estimation from the sensor. See also setZeroPosition().
Returns a 12-bit value as unsigned int.

Functionality not covered by the above higher-level methods can be easily added using the low-level communication methods. The already included register address maps facilitate this. In any case, giving the datasheet a read is highly recommended to understand how the sensor works.

bitfasching / AS5601