as5040 austriamicrosystems, as5040 Datasheet - Page 11

• Manufacturer Part Number: as5040
• Description: 10-bit Programmable Magnetic Rotary Encoder
• Manufacturer: austriamicrosystems

Q uad A/B-M ode
AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
6
Three different incremental output modes are possible
with quadrature A/B being the default mode.
Figure 8 shows the two-channel quadrature as well as
the step / direction incremental signal (LSB) and the
direction bit in clockwise (CW) and counter-clockwise
(CCW) direction.
6.1
The phase shift between channel A and B indicates the
direction of the magnet movement. Channel A leads
channel B at a clockwise rotation of the magnet (top
view) by 90 electrical degrees. Channel B leads channel
A at a counter-clockwise rotation.
Revision 1.8
Step / Dir-Mode
CLK
CSn
DO
Incremental Outputs
t
Quadrature A/B Output
(Quad A/B Mode)
DO active
Index
A
B
Dir
CSn
LSB
t
CLK FE
t
Increm ental outputs valid
T
CLK/2
t
1
DO valid
D9
D8
D7
D6
Angular Position Data
D5
Figure 7: Daisy Chain mode data transfer
D4
Figure 8: Incremental output modes
Clockwise cw
D3
8
D2
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Zero Position
D1
M echanical
Index=0
Index=1
1LSB
3 LSB
1
D0
st
Device
6.2
Output LSB reflects the LSB (least significant bit) of the
programmed incremental resolution (OTP Register Bit
Div0, Div1). Output Dir provides information about the
rotational direction of the magnet, which may be placed
above or below the device (1=clockwise; 0=counter
clockwise; top view). Dir is updated with every LSB
change.
In both modes (quad A/B, step/direction) the resolution
and the index output are user programmable. The index
pulse indicates the zero position and is by default one
angular step (1LSB) wide. However, it can be set to three
LSBs by programming the Index-bit of the OTP register
accordingly (see Table 6).
OCF
COF
LSB Output (Step / Direction Mode)
Rotation Direction
Status Bits
LIN
Change
Mag
INC
t
H yst =
2 LSB
D ir valid
DEC
Mag
16
Even
PAR
Zero Position
Counterclockwise ccw
M echanical
D
Angular Position Data
2
1
D9
nd
Device
2
D8
3
D7
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