6 Channel Capacitive Touch Sensor with 2 LED Drivers
Datasheet
based on the active channels. The device will still respond to communications normally and can
be returned to the Fully Active state of operation by clearing the STBY bit.
3. Deep Sleep - The device is in its lowest power state. It is not monitoring any Capacitive Sensor
channels. It can be awakened by SMBus or SPI communications targeting the device (which will
cause the DSLEEP bit to be automatically cleared).
If the device is not communicating via the 4-wire SPI bus, then during this state of operation, if the
WAKE/SPI_MOSI pin is driven high by an external source, the device will clear the DSLEEP bit
and return to Fully Active.
APPLICATION NOTE: The Deep Sleep state does not change LED drive behavior so it is It is the user’s
responsibility to ensure that the LEDs are driven to the desired state prior to entering Deep
Sleep. This is best achieved by unlinking the LEDs from the sensors and driving the LEDs
to the desired state using the LED Output Control register.
APPLICATION NOTE: If the CAP1026 is configured to communicate using the BC-Link protocol, the device does
not support Deep Sleep.
4.2
4.3
RESET Pin
The RESET pin is an active high reset that is driven from an external source. While it is asserted high,
all the internal blocks will be held in reset including the communications protocol used. No Capacative
Touch sensors will be sampled and the LEDs will not be driven.
All configuration settings will be reset to default states (thus waking the device from Deep Sleep) and
all readings will be cleared. Once the RESET pin is pulled low, the CAP1026 will begin operation as
if a power-on-reset had occurred.
WAKE/SPI_MOSI Pin Operation
When the CAP1026 is placed in Standby, and is not communicating using the 4-wire SPI protocol,it
will assert the WAKE/SPI_MOSI pin when a touch is detected on one of its sampled sensors. The pin
will remain asserted until the INT bit has been cleared and then it will be de-asserted.
When the CAP1026 is placed in Deep Sleep and it is not commuicating using the 4-wire SPI protocol,
the WAKE/SPI_MOSI pin is monitored by the device as an input. If the WAKE/SPI_MOSI pin is driven
high by an external source, the CAP1026 will clear the DSLEEP bit.
When the device is placed in Deep Sleep, this pin is a High-Z input and must have a pull-down resistor
to GND for proper operation.
4.4
LED Drivers
The CAP1026 contains two (2) LED Drivers. Each LED driver can be configured to operate in one of
the following modes with either push-pull or open drain drive. Additionally, each LED driver can be
linked to the respective Capacitive Touch sensor input.
1. Direct - The LED is configured to be on or off when the corresponding input stimulus is on or off
(or inverted). The brightness of the LED can be programmed from full off to full on (default).
Additionally, the LED contains controls to individually configure ramping on, off, and turn-off delay.
2. Pulse 1 - The LED is configured to fade ON-OFF-ON a programmable number of times with
programmable rate and min / max brightness. This behavior may be actuated when a press is
detected, or when a release is detected.
3. Pulse 2 - The LED is configured to “Breathe” while actuated and then “Pulse” when the sensor is
released.
4. Breathe - The LED is configured to fade continuously ON-OFF-ON (i.e. to "Breathe”) with a
programmable rate and min / max brightness.
SMSC CAP1026
Revision 1.1 (08-05-09)
DATA2S9HEET
SMSC [ SMSC CORPORATION ]
