IC-TW11 Datasheet, PDF (14/25 Pages) IC-Haus GmbH – 10-BIT ULTRA LOW POWER MAGNETIC ABSOLUTE ROTARY ENCODER

iC-TW11 10-BIT ULTRA LOW POWER^preliminary
MAGNETIC ABSOLUTE ROTARY ENCODER
Rev B1, Page 14/25
ANGLE Register
The ANGLE register is a 16-bit read-only register that
contains the most recently converted angular position
of the magnet.
ANGLE Register
Bit
Name
15
busy
14
warn
13:10
gain
9:0
angle
Addr. 0x00
Description
Busy; angle is undefined
Conversion warning
4 MSBs of Hall array gain
10-bit angle
Depending on the application requirements, if AN-
GLE.warn = 1, the conversion may need to be per-
formed again. Typically, occasional or random con-
version warnings may be safely ignored; consistent
warnings may indicate a misaligned magnet or loss of
magnet (airgap too large).
SIN Register
The SIN register is a 16-bit read-only register that con-
tains the sine component used to calculate the most
recently converted angular position of the magnet.
Table 9: ANGLE Register
The angle is returned as a positive integer in the range
of 0-1023 (0x000-0x3FF). The magnet angle in degrees
is calculated as
When reading the SIN register, it is recommended to
suppress the next sample by setting sup = 1 in the com-
mand packet. This ensures that the sine value read is
consistent with the angle calculated from the previous
(most recent) sample.
Angle [^◦] = Sampled Angle · ³⁶⁰
1024
ANGLE.gain (bits 13-10) is the 4 most significant bits of
the current Hall array gain and is returned as a positive
integer in the range 0-8. Hall array gain is proportional
to the airgap between the magnet and the iC-TW11 (a
larger airgap requires more gain) and thus gain can be
used in pushbutton applications to detect if the knob is
pressed or released. The full 5-bit gain value is avail-
able in the GAIN register (0x23).
The busy bit, busy (bit 15) indicates whether or not
a conversion is in process. If ANGLE.busy = 0, the
conversion is complete and ANGLE.angle is valid. If
ANGLE.busy = 1, the conversion is in process and AN-
GLE.angle is undefined.
The conversion warning bit, warn (bit 14) shows
whether an ADC over- or underflow occurred during
the conversion. If ANGLE.warn = 0, no over- or under-
flow occurred. If ANGLE.warn = 1, one of the following
occurred:
SIN Register
Bit
Name
15
busy
14
warn
13:12
-
11:0
sine
Description
Busy; sine is undefined
Conversion warning
Reserved (0)
12-bit sine of angle
Addr. 0x01
Table 10: SIN Register
SIN.sine is returned as a signed 2’s complement
value in the range ±1533 (±0x5FD). The magnitude
of SIN.sine depends on the strength of the magnetic
field and the gain in use when the sample was taken.
The busy bit, busy (bit 15) indicates whether or not a
conversion is in process. If SIN.busy = 0, the conver-
sion is complete and SIN.sine is valid. If SIN.busy = 1,
the conversion is in process and SIN.sine is undefined.
The conversion warning bit, warn (bit 14) shows
whether an ADC over- or underflow occurred during
the conversion. If SIN.warn = 0, no over-or underflow
occurred. If SIN.warn = 1, an ADC over- or underflow
occurred. See ANGLE register for more information.
1. ADC overflow. The measured Hall signal ampli-
tudes were too high. The AGC lowers the Hall
sensor gain for the next conversion. An ADC
overflow status bit is also available. See STATUS
register on page 16 for more information.
COS Register
The COS register is a 16-bit read-only register that con-
tains the cosine component used to calculate the most
recently converted angular position of the magnet.
2. ADC underflow. The measured Hall signal am-
plitudes were too low. The AGC raises the Hall
sensor gain for the next conversion. An ADC un-
derflow status bit is also available. See STATUS
register on page 16 for more information.
When reading the COS register, it is recommended
to suppress the next sample by setting sup = 1 in the
command packet. This ensures that the cosine value
read is consistent with the angle calculated from the
previous (most recent) sample.