sx8638 Semtech Corporation, sx8638 Datasheet - Page 16

• Manufacturer Part Number: sx8638
• Description: Low Power, Capacitive Button And Slider Touch Controller 8 Sensors With Enhanced Led Drivers And Proximity
• Manufacturer: Semtech Corporation

SX8638
Low Power, Capacitive Button and Slider Touch Controller
(8 sensors) with Enhanced LED Drivers and Proximity
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
max
min
....x...
position
Slider Position
Figure 13
The position belonging to the minimum and associated to a sensor is defined arbitrarily. The SX8638 defines the
minimum position to the sensor with the lowest CAP pin index. E.g. if CAP0 is a button (or disabled) and CAP1 to
CAP7 are the sensors of the slider then the position ‘zero’ starts at CAP1 and the maximum is found at CAP7.
In addition to the slider position, the SX8638 allows to detect finger movements. The movement occurs if the
finger position changes a certain step size between two succeeding scan periods. A very slow moving finger will
not be considered as a movement as the changing position will be minor. The SX8638 allows detecting a move
low (direction max to min) (see Figure 14) and a move high (direction min to max) (see Figure 15).
min
max
Slider Move Low
Figure 14
Slider Move High
Figure 15
Revision 7_6, September 10
© 2010 Semtech Corp.
www.semtech.com
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