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 t
CLK 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 t
CSn.
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
OCF
COF
LIN
Mag
INC
0
1
0
0
0
1
Mag
DEC
0
1
0
even checksum of bits 1:15
Parity
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
CSn
t
CLK FE
T
CLK / 2
1
8
16
t
CSn
t
CLK FE
CLK
1
DO
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
OCF
COF
LIN
Mag
INC
Mag
DEC
Even
PAR
D9
t
DO active
t
DO valid
Angular Position Data
Status Bits
t
DO Tristate
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