CAP1106

DS00001624B-page 24

 2015 Microchip Technology Inc.

6.6

Configuration Registers

The Configuration registers control general global functionality that affects the entire device.

6.6.1

CONFIGURATION - 20H

Bit 7 - TIMEOUT - Enables the timeout and idle functionality of the SMBus protocol.

• ‘0’ (default for Functional Revision C) - The SMBus timeout and idle functionality are disabled. The SMBus inter-

face will not time out if the clock line is held low. Likewise, it will not reset if both the data and clock lines are held

• ‘1’ (default for Functional Revision B) - The SMBus timeout and idle functionality are enabled. The SMBus inter-

face will time out if the clock line is held low for longer than 30ms. Likewise, it will reset if both the data and clock

lines are held high for longer than 200us.

Bit 5 - DIS_DIG_NOISE - Determines whether the digital noise threshold (see Section 6.19, "Sensor Input Noise Thresh-

old 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 6.8).

6.6.2

CONFIGURATION 2 - 44H

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 con-

version 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 3 - SHOW_RF_NOISE - Determines whether the Noise Status bits will show RF Noise as the only input source.

• ‘0’ (default) - The Noise Status registers will show both RF noise and low frequency EMI noise if either is detected

on a capacitive touch sensor input.

• ‘1’ - The Noise Status registers will only show RF noise if it is detected on a capacitive touch sensor input. EMI

TABLE 6-10:

CONFIGURATION REGISTERS

ADDR

R/W

Register

B7

B6

B5

B4

B3

B2

B1

B0

Default

20h

R/W

Configuration

TIMEOUT

-

DIS_ DIG_

NOISE

DIS_ ANA_

NOISE

MAX_

DUR_EN

--

-

A0h

(Rev B)

20h

(rev C)

44h

R/W

Configuration 2

-ALT_

POL

BLK_PWR_

CTRL

-

SHOW_

RF_

NOISE

DIS_

RF_

NOISE

-

INT_

REL_n

40h