AS5040_1 AMSCO [austriamicrosystems AG], AS5040_1 Datasheet - Page 10

• Manufacturer Part Number: AS5040_1
• Description: 10Bit 360 Programmable Magnetic Rotary Encoder
• Manufacturer: AMSCO [austriamicrosystems AG]

AS5040
Data Sheet
7 10-bit Absolute Angular Position Output
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.
Data Content:
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).
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CLK
CSn
DO
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.
After a minimum time t
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) .
A subsequent measurement is initiated by a log. “high” pulse at CSn with a minimum duration of t
t
DO active
t
CLK FE
T
t
DO valid
CLK / 2
1
D9
D8
CLK FE,
D7
data is latched into the output shift register with the first falling edge of CLK.
D6
Angular Position Data
D5
D4
D3
8
D2
Revision 2.10
D1
D0
OCF
COF
Status Bits
LIN
Mag
I N C
D EC
M ag
16
Even
PAR
t
DO Tristate
t
CSn
CSn.
t
CLK FE
10 - 33
1
D9