8 Channel Capacitive Touch Sensor with 2 LED Drivers
Datasheet
‘1’ - The WAKE pin will be asserted high when a touch is detected while the device is in Standby.
It will also be used to wake the device from Deep Sleep when driven high.
Bit 5 - DIS_DIG_NOISE - Determines whether the digital noise threshold (see Section 5.19, "Sensor
Input Noise Threshold Register") is used by the device. Setting this bit disables the feature.
‘0’ - The digital noise threshold is used. If a delta count value exceeds the noise threshold but does
not exceed the touch threshold, the sample is discarded and not used for the automatic re-
calibration routine.
‘1’ (default) - The noise threshold is disabled. Any delta count that is less than the touch threshold
is used for the automatic re-calibration routine.
Bit 4 - DIS_ANA_NOISE - Determines whether the analog noise filter is enabled. Setting this bit
disables the feature.
‘0’ (default) - If low frequency noise is detected by the analog block, the delta count on the
corresponding channel is set to 0. Note that this does not require that Noise Status bits be set.
‘1’ - A touch is not blocked even if low frequency noise is detected.
Bit 3 - MAX_DUR_EN - Determines whether the maximum duration recalibration is enabled.
‘0’ (default) - The maximum duration recalibration functionality is disabled. A touch may be held
indefinitely and no re-calibration will be performed on any sensor input.
‘1’ - The maximum duration recalibration functionality is enabled. If a touch is held for longer than
the MAX_DUR bit settings, then the re-calibration routine will be restarted (see Section 5.8).
5.6.2
Configuration 2 - 44h
Bit 7 - INV_LINK_TRAN - Determines the behavior of the Linked LED Transition controls (see
Section 5.29).
‘0’ (default) - The Linked LED Transition controls set the min duty cycle equal to the max duty cycle.
‘1’ - The Linked LED Transition controls will invert the touch signal. For example, a touch signal
will be inverted to a non-touched signal.
Bit 6 - ALT_POL - Determines the ALERT# pin polarity and behavior.
‘0’ - The ALERT# pin is active high and push-pull.
‘1’ (default) - The ALERT# pin is active low and open drain.
Bit 5 - BLK_PWR_CTRL - Determines whether the device will reduce power consumption while waiting
between conversion time completion and the end of the polling cycle.
‘0’ (default) - The device will always power down as much as possible during the time between the
end of the last conversion and the end of the polling cycle.
‘1’ - The device will not power down the Cap Sensor during the time between the end of the last
conversion and the end of the polling cycle.
Bit 4 - BLK_POL_MIR - Determines whether the LED Mirror Control register bits are linked to the LED
Polarity bits. Setting this bit blocks the normal behavior which is to automatically set and clear the LED
Mirror Control bits when the LED Polarity bits are set or cleared.
‘0’ (default) - When the LED Polarity controls are set, the corresponding LED Mirror control is
automatically set. Likewise, when the LED Polarity controls are cleared, the corresponding LED
Mirror control is also cleared.
‘1’ - When the LED Polarity controls are set, the corresponding LED Mirror control is not
automatically set.
Bit 3 - SHOW_RF_NOISE - Determines whether the Noise Status bits will show RF Noise as the only
input source.
SMSC CAP1128
Revision 1.32 (01-05-12)
DATA4S7HEET
SMSC [ SMSC CORPORATION ]
