Multiple Channel Capacitive Touch Sensor and LED Driver
Datasheet
4.5.3
Slider
The Grouped sensors have the capability to detect a slide in either the “Up” or “Down” direction as
referenced by the sensor numbers that are used. For example, an “Up” direction slide would be
detected if CS8 detected a touch, followed by CS9, then by CS10 etc. Likewise, a “Down” direction
slide would be detected if CS10 detected a touch, followed by CS9, then by CS8 etc.
Slides in either direction are configured to flag an interrupt and to cause an LED to be actuated
(separate for each direction). The Slide is detected independently of a Press and Hold or a Tap
condition and only one condition may be present at any one time.
So long as a slide is maintained in either direction, it will flag an interrupt at the programmed repeat
rate (as determined by the RPT_RATE_SL bit settings). If the slide is removed or changes direction,
then it will reset and return to normal operation.
4.5.4
4.5.5
Relative Position
The CAP1014 has the option to indicate the relative position of a touch on the Grouped sensors. This
value is stored either as a scaled number from 2 to 98 indicating where a tap, press and hold, or the
end of a slide was detected or as a 8-bit number that represents volumetric data. When configured to
store volumetric data, the user may write a base setting at any time that is modified based on Grouped
sensor behavior (see Section 5.4).
Slider Velocity
The repeat rate can be dynamically increased based on the speed of a slide. This permits slow sliding
motions to have precise, step-by-step volume control and faster motions to generate increasingly fast
volume changes.
Two techniques are employed to make increase the number of interrupts generated based on speed.
First, the slide speed is measured and the repeat rate is increased to provide more interrupts for the
same distance traveled relative to a slower slide. Second, additional interrupts are generated
immediately after the slide ends to further increase the change in volume. The number of additional
interrupts is based on slide speed; both of these dynamic slider behaviors are controlled by the Slider
Velocity Register.
4.6
ALERT Pin
The ALERT pin is an active high output that is driven high when an interrupt event is detected. It is
also used to wake the device from Deep Sleep mode.
Whenever an interrupt is generated, the INT bit (see Section 5.1) is set. The ALERT pin is cleared
when INT bit is cleared by the user. Additionally, when the INT bit is cleared by the user status bits
are cleared only if no press is detected.
4.6.1
4.6.2
Button Interrupt Behavior
For non-grouped buttons, an interrupt is generated when a touch is detected. If the repeat rate is
enabled (see Section 5.14), then, so long as the touch is held, another interrupt will be generated
based on the programmed repeat rate (see Figure 4.2). An interrupt will be generated whenever a
release is detected (see Figure 4.3).
Grouped Sensor Interrupt Behavior
For grouped sensors, an interrupt is generated upon initial detection of a tap, slide, or press and hold
event. Then, subsequent interrupts are generated as follows:
1. For a slide event, an interrupt is generated based on the programmed repeat rate as well as the
velocity of the slide operation. See Figure 4.6 and Figure 4.7. Additionally, additional interrupts are
Revision 1.65 (08-11-09)
SMSC CAP1014
DATA2S4HEET
SMSC [ SMSC CORPORATION ]
