AS5043
Data Sheet – 10-bit Absolute Synchronous Serial Interface (SSI)
8 10-bit Absolute Synchronous Serial Interface (SSI)
The serial data transmission timing is outlined in Figure 5: if CSn changes to logic low, Data Out (DO) will change from
high impedance (tri-state) to logic high and the read-out sequence will be initiated.
After a minimum time tCLK FE, data is latched into the output shift register with the first falling edge of CLK.
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 / out
of range) .
A subsequent measurement is initiated by a logic “high” pulse at CSn with a minimum duration of tCSn.
Data transmission may be terminated at any time by pulling CSn = high.
8.1 Serial Data Contents
D9:D0 absolute angular position data (MSB is clocked out first).
OCF (Offset Compensation Finished), logic high indicates that the Offset Compensation Algorithm has finished and data
is valid.
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 may contain invalid data. This warning may be resolved by
bringing the magnet within the X-Y-Z tolerance limits.
Data D9:D0 is valid, when the status bits have the following configurations:
Table 2: Status Bit Outputs
Mag
INC
Mag
DEC
OCF
COF
LIN
Parity
0
0
1
0
1
0
1
0
0
even checksum of bits 1:15
MagInc, (Magnitude Increase) becomes HIGH, when the magnet is pushed towards the IC, thus the magnetic field
strength is increasing.
MagDec, (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).
Note: Pin 1 (MagRngn) is a combination of MagInc and MagDec. It is active low via an open drain output and requires an
external pull-up resistor. If the magnetic field is in range, this output is turned off. (logic “high”).
Even Parity bit for transmission error detection of bits 1…15 (D9…D0, OCF, COF, LIN, MagInc, MagDec)
The absolute angular output is always set to a resolution of 10 bit / 360°. Placing the magnet above the chip, angular
values increase in clockwise direction by default.
Figure 5: Synchronous Serial Interface with Absolute Angular Position Data
t CLK FE
CSn
CLK
DO
t CLK FE T CLK / 2
t CSn
1
1
8
16
Even
PAR
Mag
DEC
Mag
INC
D9
D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 OCF COF LIN
t DO valid
t DO active
Status Bits
t DO Tristate
Angular Position Data
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