CAP1028 Datasheet, PDF (27/71 Pages) SMSC Corporation – 8 Channel Capacitive Touch Sensor with 2 LED Drivers

8 Channel Capacitive Touch Sensor with 2 LED Drivers
Datasheet
Chapter 4 General Description
The CAP1028 is a multiple channel Capacitive Touch sensor with multiple power LED drivers. It
contains eight (8) individual Capacitive Touch sensor inputs with programmable sensitivity for use in
touch sensor applications. Each sensor automatically recalibrates to compensate for gradual
environmental changes.
The CAP1028 also contains two (2) low side (or push-pull) LED drivers that offer full-on / off, variable
rate blinking, dimness controls, and breathing. Each of the LED drivers may be linked to one of the
sensors to be actuated when a touch is detected. As well, each LED driver may be individually
controlled via a host controller.
Finally, the device contains a dedicated RESET pin to act as a soft reset by the system.
The CAP1028 offers multiple power states operating at low quiescent currents during its Deep Sleep
state. The device also contains a wake pin (WAKE/SPI_MOSI) output to wake the system when a
touch is detected in Standby and to wake the device from Deep Sleep. It can monitor one or more
channels while in a lower power state and respond to communications normally.
The device communicates with a host controller using the SPI bus, SMSC BC-Link bus, or via SMBus
/ I²C. The host controller may poll the device for updated information at any time or it may configure
the device to flag an interrupt whenever a touch is detected on any sensor.
A typical system diagram is shown in Figure 4.1.
SMSC CAP1028
27
DATASHEET
Revision 1.1 (08-05-09)