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AS5140H
Data Sheet - Detailed Description
7.6.7   Zero Position Programming
Zero position programming is an OTP option that simplifies assembly of a system, as the magnet does not need to be manually adjusted to the
mechanical zero position. Once the assembly is completed, the mechanical and electrical zero positions can be matched by software. Any
position within a full turn can be defined as the permanent new zero/index position. For zero position programming, the magnet is turned to the
mechanical zero position (e.g. the off-position of a rotary switch) and the actual angular value is read.
7.7 Alignment Mode
The alignment mode simplifies centering the magnet over the center of the chip to gain maximum accuracy. Alignment mode can be enabled with
the falling edge of CSn while Prog = logic high (see Figure 16). The Data bits D9-D0 of the SSI change to a 10-bit displacement amplitude
output. A high value indicates large X or Y displacement, but also higher absolute magnetic field strength. The magnet is properly aligned, when
the difference between highest and lowest value over one full turn is at a minimum. Under normal conditions, a properly aligned magnet will
result in a reading of less than 128 over a full turn. The MagINCn and MagDECn indicators will be = 1 when the alignment mode reading is < 128.
At the same time, both hardware pins MagINCn (#1) and MagDECn (#2) will be pulled to VSS. A properly aligned magnet will therefore produce
a MagINCn = MagDECn = 1 signal throughout a full 360?turn of the magnet. Stronger magnets or short gaps between magnet and IC may show
values larger than 128. These magnets are still properly aligned as long as the difference between highest and lowest value over one full turn is
at a minimum. The Alignment mode can be reset to normal operation by a power-on-reset (disconnect / re-connect power supply) or by a falling
edge on CSn with Prog = low.
Table 20. One Time Programmable (OTP) Register Options
Mode
OTP-Mode-Register-Bit
Pin#
Pulses per
Revolution
Incremental
Resolution
Md1
Md0
Div1
Div0
Index
3
4
6
12
ppr
bit
Default (Mode0.0)
1
1. Div1, Div0 and Index cannot be programmed in Mode 0:0
0
0
0
0
0
A
B
1LSB
PWM
10 bit
2 x 256
10
quadAB-Mode1.0
0
1
0
0
0
1LSB
quadAB-Mode1.1
0
1
0
0
1
3LSBs
quadAB-Mode1.2
0
1
0
1
0
1LSB
2 x 128
9
quadAB-Mode1.3
0
1
0
1
1
3LSBs
quadAB-Mode1.4
0
1
1
0
0
1LSB
2 x 64
8
quadAB-Mode1.5
0
1
1
0
1
3LSBs
quadAB-Mode1.6
0
1
1
1
0
1LSB
2 x 32
7
quadAB-Mode1.7
0
1
1
1
1
3LSBs
Step/Dir-Mode2.0
1
0
0
0
0
LSB
Dir
1LSB
PWM
10 bit
512
10
Step/Dir-Mode2.1
1
0
0
0
1
3LSBs
Step/Dir -Mode2.2
1
0
0
1
0
1LSB
256
9
Step/Dir -Mode2.3
1
0
0
1
1
3LSBs
Step/Dir -Mode2.4
1
0
1
0
0
1LSB
128
8
Step/Dir -Mode2.5
1
0
1
0
1
3LSBs
Step/Dir -Mode2.6
1
0
1
1
0
1LSB
64
7
Step/Dir -Mode2.7
1
0
1
1
1
3LSBs
Commutation-Mode3.0
1
1
0
0
0
U(0?   V(120?
W(240?
LSB
3 x 1
10
Commutation-Mode3.1
1
1
0
1
0
9
Commutation-Mode3.2
1
1
1
0
0
U
(0?18
0?
V
(60?240?/DIV>
)
W
(120?300?
LSB
2 x 3
10
Commutation-Mode3.3
1
1
1
1
0
9