/// <summary>
/// Sets or clears one or more bits on the AK8963 magnetometer.
/// </summary>
/// <param name="register">Magnetometer register</param>
/// <param name="mask"> Mask of the bit to set or clear according to value. Supports setting or clearing multiple bits.</param>
/// <param name="value">Value of the bits, i.e. set or clear.</param>
/// <returns>Value written to register</returns>
/// <remarks>
/// Commonly used to set register flags. Reads the current byte value, merges the positive or negative bit mask according to value,
/// then writes the modified byte back.
/// </remarks>
private byte ReadWriteAK8963(Mpu9250MagRegister register, byte mask, bool value)
{
// Read existing byte
var oldByte = ReadAK8963(register);
// Merge bit (set or clear bit accordingly)
var newByte = value ? (byte)(oldByte | mask) : (byte)(oldByte & ~mask);
// Write new byte
WriteAK8963(register, newByte);
// Return the value written.
return(newByte);
}
/// <summary>
/// Writes a single byte to the AK8963 magnetometer register.
/// </summary>
/// <param name="register">Magnetometer register.</param>
/// <param name="data">Data to write.</param>
private void WriteAK8963(Mpu9250MagRegister register, byte data)
{
// Set I2C slave address of the AK8963 and set for write.
Hardware.WriteJoinByte((byte)Mpu9250Register.I2cSlave0Address, (byte)Mpu9250MagRegister.Ak8963I2cAddress);
// Set I2C slave register address from where to begin data transfer.
Hardware.WriteJoinByte((byte)Mpu9250Register.I2cSlave0Register, (byte)register);
// Set I2C data written to I2C slave.
Hardware.WriteJoinByte((byte)Mpu9250Register.I2cSlave0DO, data);
// Set I2C enable and set 1 byte.
Hardware.WriteJoinByte((byte)Mpu9250Register.I2cSlave0Control, 0x81);
// Wait for write completion
Task.Delay(WriteDelay).Wait();
}
/// <summary>
/// Reads one or more bytes from the AK8963 magnetometer register.
/// </summary>
/// <param name="register">External sensor data to read register.</param>
/// <param name="magRegister">Magnetometer register.</param>
/// <param name="control">Magnetometer register.</param>
/// <param name="size">Amount of bytes to read.</param>
/// <returns>Read register bytes.</returns>
private byte[] ReadAK8963(Mpu9250Register register, Mpu9250MagRegister magRegister, byte control, int size)
{
// Validate size to make sure it's not out of the range for an sbyte type.
if (size < -128 & size > 127)
{
throw new ArgumentOutOfRangeException(nameof(size));
}
// Set I2C slave address of the AK8963 and set for read.
Hardware.WriteJoinByte((byte)Mpu9250Register.I2cSlave0Address, (byte)Mpu9250MagRegister.Ak8963I2cAddress | SpiExtensions.ReadFlag);
// Set I2C slave 0 register address from where to begin data transfer.
Hardware.WriteJoinByte((byte)Mpu9250Register.I2cSlave0Register, (byte)magRegister);
// Read bytes from the magnetometer
Hardware.WriteJoinByte((byte)Mpu9250Register.I2cSlave0Control, control);
// Wait for write completion
Task.Delay(WriteDelay).Wait();
// Read the data out registers
return(Hardware.WriteReadBytes((byte)register, size));
}
/// <summary>
/// Reads one or more bytes from the AK8963 magnetometer register.
/// </summary>
/// <param name="register">Magnetometer register.</param>
/// <param name="size">Amount of bytes to read.</param>
/// <returns>Read register bytes.</returns>
private byte[] ReadAK8963(Mpu9250MagRegister register, int size)
{
// Read the data out registers
return(ReadAK8963(Mpu9250Register.ExternalSensorData00, register, (byte)((sbyte)size | 0x80), size));
}
/// <summary>
/// Reads a single byte result from the AK8963 magnetometer register.
/// </summary>
/// <param name="register">Magnetometer register.</param>
/// <returns>Read register byte.</returns>
private byte ReadAK8963(Mpu9250MagRegister register)
{
return(ReadAK8963(register, 1)[0]);
}