AS5040

Data Sheet

www.austriamicrosystems.com

Revision 2.10

10 - 33

7

10-bit Absolute Angular Position Output

Synchronous Serial Interface (SSI)

Figure 5: Synchronous Serial Interface with Absolute Angular Position Data

Even

PAR

CSn

CLK

DO

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

18

16

COF

LIN

OCF

Mag

INC

Mag

DEC

1

D9

Angular Position Data

Status Bits

If CSn changes to logic low, Data Out (DO) will change from high impedance (tri-state) to logic high and the read-out

will be initiated.

Each subsequent rising CLK edge shifts out one bit of data.

The serial word contains 16 bits, the first 10 bits are the angular information D[9:0], the subsequent 6 bits contain

system information, about the validity of data such as OCF, COF, LIN, Parity and Magnetic Field status

(increase/decrease) .

Data Content:

D9:D0 absolute angular position data (MSB is clocked out first)

OCF

(Offset Compensation Finished), logic high indicates the finished Offset Compensation Algorithm.

For fast startup, this bit may be polled by the external microcontroller. As soon as this bit is set, the AS5040 has

completed the startup and the data is valid (see Table 4)

COF

(Cordic Overflow), logic high indicates an out of range error in the CORDIC part. When this bit is set, the

data at D9:D0 is invalid. The absolute output maintains the last valid angular value.

This alarm may be resolved by bringing the magnet within the X-Y-Z tolerance limits.

LIN

(Linearity Alarm), logic high indicates that the input field generates a critical output linearity.

When this bit is set, the data at D9:D0 may still be used, but can contain invalid data. This warning may be

resolved by bringing the magnet within the X-Y-Z tolerance limits.

MagINCn

, (Magnitude Increase) becomes HIGH, when the magnet is pushed towards the IC, thus the magnetic field

strength is increasing.

MagDECn,

(Magnitude Decrease) becomes HIGH, when the magnet is pulled away from the IC, thus the magnetic

field strength is decreasing.

Both signals HIGH indicate a magnetic field that is out of the allowed range (see Table 3).