CAP1293 datasheet(14/63 Pages) MICROCHIP

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CAP1293

DS00001566B-page 14

 2013-2015 Microchip Technology Inc.

4.0

GENERAL DESCRIPTION

The CAP1293 is a multiple channel capacitive touch sensor. It contains three (3) individual capacitive touch sensor

inputs with programmable sensitivity for use in touch sensor applications. Each sensor input is calibrated to compensate

for system parasitic capacitance and automatically recalibrated to compensate for gradual environmental changes.

In addition, the CAP1293 can be configured to detect proximity on one or more channels with an optional signal guard

to reduce noise sensitivity.

The CAP1293includes Multiple Pattern Touch recognition that allows the user to select a specific set of buttons to be

touched simultaneously. If this pattern is detected, a status bit is set and an interrupt is generated.

The CAP1293 has Active and Standby states, each with its own sensor input configuration controls. The Combo state

allows a combination of sensor input controls to be used which enables one or more sensor inputs to operate as buttons

while another sensor input is operating as a proximity detector. Power consumption in the Standby and Combo states

is dependent on the number of sensor inputs enabled as well as averaging, sampling time, and cycle time. Deep Sleep

is the lowest power state available, drawing 5µA (typical) of current. In this state, no sensor inputs are active, and com-

munications will wake the device.

The device communicates with a host controller using 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

pad.

A typical system diagram is shown in FIGURE 4-1:.

4.1

Power States

The CAP1293 has 4 power states depending on the status of the STBY, COMBO, and DSLEEP bits. When the device

transitions between power states, previously detected touches (for channels that are being de-activated) are cleared

and the sensor input status bits are reset.

Active - The normal mode of operation. The device is monitoring capacitive sensor inputs enabled in the Active

state.

FIGURE 4-1:

SYSTEM DIAGRAM FOR CAP1293

CAP1293

Embedded

Controller

3.0V to 5.5V

CS3

CS1

Touch

Button

SG*

Proximity

Sensor

VDD

GND

* CS2 / SG is a multi-function pin. If not

using the signal guard shown here, CS2

can be another touch button.

10kOhm

resistors

3.0V to 5.5V

1.0uF

0.1uF

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