TMD2725 Datasheet, PDF (34/50 Pages) ams AG – The device features advanced proximity measurement

TMD2725 − RegisterDescription
Figure 49:
CALIB Register
CALIB Register (Address 0xD7)
Addr: 0xD7
Bit
Bit Name
7:6
Reserved
Default
0
5
ELECTRICAL_
CALIBRATION
0
4:1
Reserved
0
0
START_OFFSET_
CALIB
0
Access
RO
RW
RW
CALIB
Bit Description
Reserved
Selects proximity calibration type.
1 = electrical offset only.
0 = calibration compensates for electrical and
optical crosstalk.
Reserved
RW
Set to 1 to start a calibration sequence.
Proximity response in systems with electrical and optical
crosstalk may be improved by using the calibration feature.
Optical crosstalk is caused when the photodiode receives a
small portion of the LED IR which was unintentionally reflected
by a surface other than the target. Electrical offset is caused by
electrical disturbance in the sensor AFE, and also influences the
proximity result. The calibration routine adjusts the value in
registers C0 and C1 until the proximity result is as close to
BINSRCH_TARGET as possible without becoming zero.
Optical and electrical calibration function identically, except
that during an electrical calibration the proximity photodiode
is disconnected from the AFE.
Upon power-up, the device always automatically performs an
electrical calibration. However, an electrical calibration can be
initiated anytime by setting the ELECTRICAL_CALIBRATION and
START_OFFSET_CALB bits.
To perform an optical (and electrical) calibration do not set the
ELECTRICAL_CALIBRATION bit when setting the START_
OFFSET_CALIB. The CINT flag will assert after calibration has
finished.
Upon completion Proximity offset registers are automatically
loaded with calibration result.
Page 34
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ams Datasheet
[v1-11] 2016-Sep-20