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AS5145

Data Sheet - D e t a i l e d D e s c r i p t i o n

8.1.1 Synchronous Serial Interface (SSI)

Figure 5. Synchronous Serial Interface with Absolute Angular Position Data

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 18 bits, the first 12 bits are the angular information D[11:0], the subsequent 6 bits contain system information,

about the validity of data such as OCF, COF, LIN, Parity and Magnetic Field status (increase/decrease).

A subsequent measurement is initiated by a “high” pulse at CSn with a minimum duration of tCSn.

Data Content

D11:D0 absolute angular position data (MSB is clocked out first)

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

COF (Cordic Overflow), logic high indicates an out of range error in the CORDIC part. When this bit is set, the data at D11: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 D11: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.

Even Parity bit for transmission error detection of bits 1…17 (D11…D0, OCF, COF, LIN, MagINC, MagDEC)

Placing the magnet above the chip, angular values increase in clockwise direction by default.

Data D11:D0 is valid, when the status bits have the following configurations:

Note:

MagInc=MagDec=1 is only recommended in YELLOW mode (see Table 9)

Table 8. Status Bit Outputs

OCF

COF

LIN

Mag INC

Mag DEC

Parity

10

0

00

Even checksum of bits

1:15

01

10

11

CSn

CLK

DO

Angular Position Data

Status Bits

1

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0 OCF COF LIN

Mag

INC

Mag

DEC

Even

PAR

8

18

1

D11

D10

D11