CAP1133 datasheet(23/63 Pages) MICROCHIP

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DS00001625B-page 23

CAP1133

All bits are cleared when the INT bit is cleared and if a touch on the respective capacitive touch sensor input is no longer

present. If a touch is still detected, the bits will not be cleared (but this will not cause the interrupt to be asserted - see

Section 6.6).

Bit 2 - CS3 - Indicates that a touch was detected on Sensor Input 3. This sensor input can be linked to LED3.

Bit 1 - CS2 - Indicates that a touch was detected on Sensor Input 2. This sensor input can be linked to LED2.

Bit 0 - CS1 - Indicates that a touch was detected on Sensor Input 1. This sensor input can be linked to LED1.

6.2.3

LED STATUS - 04H

The LED Status Registers indicate when an LED has completed its configured behavior (see Section 6.31, "LED Behav-

ior Register") after being actuated by the host (see Section 6.28, "LED Output Control Register"). These bits are ignored

when the LED is linked to a capacitive sensor input. All LED Status bits are cleared when the INT bit is cleared.

Bit 2 - LED3_DN - Indicates that LED3 has finished its behavior after being actuated by the host.

Bit 1 - LED2_DN - Indicates that LED2 has finished its behavior after being actuated by the host.

Bit 0 - LED1_DN - Indicates that LED1 has finished its behavior after being actuated by the host.

6.3

Noise Flag Status Registers

The Noise Flag Status registers store status bits that are generated from the analog block if the detected noise is above

the operating region of the analog detector or the RF noise detector. These bits indicate that the most recently received

data from the sensor input is invalid and should not be used for touch detection. So long as the bit is set for a particular

channel, the delta count value is reset to 00h and thus no touch is detected.

These bits are not sticky and will be cleared automatically if the analog block does not report a noise error.

APPLICATION NOTE: If the MTP detection circuitry is enabled, these bits count as sensor inputs above the MTP

threshold (see Section 5.3.4, "Multiple Touch Pattern Detection") even if the corresponding

delta count is not. If the corresponding delta count also exceeds the MTP threshold, it is not

counted twice.

APPLICATION NOTE: Regardless of the state of the Noise Status bits, if low frequency noise is detected on a

sensor input, that sample will be discarded unless the DIS_ANA_NOISE bit is set. As well,

if RF noise is detected on a sensor input, that sample will be discarded unless the

DIS_RF_NOISE bit is set.

6.4

Sensor Input Delta Count Registers

The Sensor Input Delta Count registers store the delta count that is compared against the threshold used to determine

if a touch has been detected. The count value represents a change in input due to the capacitance associated with a

touch on one of the sensor inputs and is referenced to a calibrated base “Not Touched” count value. The delta is an

instantaneous change and is updated once per sensor input per sensing cycle (see Section 5.3.1, "Sensing Cycle").

TABLE 6-5:

NOISE FLAG STATUS REGISTERS

ADDR

R/W

Default

0Ah

Noise Flag Status

CS3_

NOISE

CS2_

NOISE

CS1_

NOISE

00h

TABLE 6-6:

SENSOR INPUT DELTA COUNT REGISTERS

ADDR

R/W

Default

10h

Sensor Input 1

Delta Count

Sign

00h

11h

Sensor Input 2

Delta Count

Sign

00h

12h

Sensor Input 3

Delta Count

Sign

00h

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