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Revision 1.12

7 - 22

AS5050

Datasheet - Detailed Descr i p ti on

7.1.2 Reading an Angle

The external microcontroller can respond to the INT request by reading the angle value from the AS5050 over the SPI interface. Once the angle

value is read, the INT output is cleared again.

Sending a “read angle” command by the SPI interface also automatically powers up the chip and starts another angle measurement. As soon ad

the microcontroller has completed reading of the angle value, the INT output is cleared and a new result is stored in the angle register. The

completion of the angle measurement is again indicated by setting the INT output and a corresponding flag in the status register.

(~600µs) after each power-up sequence. As soon as the measurement of one angle is completed, the chip suspends to power-down state. An

on-chip filtering of the angle value by digital averaging is not implemented, as this would require more than one angle measurement and

consequently, a longer power- up time which is not desired in low-power applications.

The angle jitter can be reduced by averaging of several angle samples in the external microcontroller. For example, an averaging of 4 samples

reduces the jitter by 6dB (50%).

7.1.3 Low Power Mode

After completing the readout of an angle value, the device is in very low power condition. The AS5050 remains in sleep mode until it receives

another angle reading request over the SPI interface. The average power consumption therefore depends on the interval, at which the external

controller reads an angle over the SPI Interface. The timing ratio between active and sleep phase:

(EQ 1)

Where:

600µs

8mA avg.

3µA

Examples:

3000 measurements per second (continuous mode)

I = 8mA

1000 measurements per second

Iavg = 5mA

100 measurements per second

Iavg = 500µA

10 measurements per second

Iavg = 53µA

Note:

is suspended to sleep mode.

7.1.4 Interrupt Chaining

Every chip contains a configurable gate to combine its own internally generated interrupt signal with a signal applied externally over the XENINT-

pin. The INT-mode register is preset via an OTP register can be overwritten by the SPI interface.

Case A.

Device A is set to mode 0

Device B is set to mode 0

The micro controller recognizes an interrupt if both devices signalize that the computation is finished.

Case B.

Device A is set to mode 0

Device B is set to mode 1

The micro controller recognizes an interrupt if one of the two devices signalize that the computation is finished.

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