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TLE5012B
Interfaces
User’s Manual
59
Rev. 1.2, 2018-02
5.6
Incremental Interface (IIF)
The
I
ncremental
I
nter
f
ace (
IIF
) emulates the operation of an optical quadrature encoder with a 50% duty cycle. It
transmits a square pulse per angle step, where the width of the steps can be configured from 9bit (512 steps per
full rotation) to 12bit (4096 steps per full rotation) within the register MOD_4 (IFAB_RES)
1)
. The rotation direction
is given either by the phase shift between the two channels IFA and IFB (A/B mode) or by the level of the IFB
channel (Step/Direction mode), as shown in
and
. The incremental interface can be
configured for A/B mode or Step/Direction mode in register MOD_1 (IIF_MOD).
Using the Incremental Interface requires an up/down counter on the microcontroller, which counts the pulses and
thus keeps track of the absolute position. The counter can be synchronized periodically by using the SSC interface
in parallel. The angle value (AVAL register) read out by the SSC interface can be compared to the stored counter
value. In case of a non-synchronization, the microcontroller adds the difference to the actual counter value to
synchronize the TLE5012B with the microcontroller.
After startup, the IIF transmits a number of pulses which correspond to the actual absolute angle value. Thus, the
microcontroller gets the information about the absolute position. The Index Signal that indicates the zero crossing
is available on the IFC pin.
Sensors with preset IIF are available as TLE5012B E1000. The register settings for these sensors can be found
in
A/B Mode
The phase shift between Phase A and Phase B is determined by the rotation direction of the magnet. By default
(ANG_DIR = 0), Phases A follows Phase B to indicate clockwise rotation direction, while Phase B follows Phase
A to indicate counterclockwise rotation direction. This behaviour is inverted by setting ANG_DIR = 1.
Figure 5-21 Incremental interface with A/B mode
Step/Direction Mode
Phase A pulses out the increments and phase B indicates the direction.
Figure 5-22 Incremental interface with Step/Direction mode
1) Decreasing the number of bits does not increase the maximum rotation speed.
90° el . Phase shift
0
1
2
3
4
5
6
7
6
5
4
3
2
1
Phase A
Counter
Phase B
Incremental Interface
(A/B Mode)
V
H
V
L
V
H
V
L
Step
Counter
Direction
Incremental Interface
(Step /Direction Mode)
V
H
V
L
V
H
V
L
0
1
2
3
4
5
6
7
6
5
4
3
2
1