as5145h austriamicrosystems, as5145h Datasheet - Page 13

• Manufacturer Part Number: as5145h
• Description: 12-bit Programmable Magnetic Rotary Encoder
• Manufacturer: austriamicrosystems

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.
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:
Table 8. Status Bit Outputs
Note: MagInc=MagDec=1 is only recommended in YELLOW mode
www.austriamicrosystems.com/AS5145
CSn
CLK
DO
After a minimum time t
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.
OCF
t
DO active
1
t
CLK FE
T
CLK/2
1
D11
CLK FE
D10
COF
t
, data is latched into the output shift register with the first falling edge of CLK.
DO valid
0
D9
D8
Angular Position Data
D7
D6
D5
LIN
0
8
D4
Revision 1.11
D3
(see Table 9)
D2
D1
Mag INC
0
0
1
1
D0
OCF COF LIN
Status Bits
Mag DEC
Mag
INC
0
1
0
1
DEC
Mag
18
Even
PAR
t
DO Tristate
t
CSn
Even checksum of bits
t
CLK FE
Parity
1:15
1
D11
13 - 36