CAP1293 datasheet(42/63 Pages) MICROCHIP

42 / 63 page

CAP1293

DS00001566B-page 42

 2013-2015 Microchip Technology Inc.

5.19

Sensor Input Threshold Registers

The Sensor Input Threshold registers store the delta threshold that is used to determine if a touch has been detected.

When a touch occurs, the input signal of the corresponding sensor pad changes due to the capacitance associated with

a touch. If the sensor input change exceeds the threshold settings, a touch is detected.

When the BUT_LD_TH bit is set (see Section 5.18 - bit 7), writing data to the Sensor Input 1 Threshold register will

update all of the Sensor Input Threshold registers (31h - 32h inclusive).

5.20

Sensor Input Noise Threshold Register

The Sensor Input Noise Threshold register controls the value of a secondary internal threshold to detect noise and

improve the automatic recalibration routine. If a capacitive touch sensor input exceeds the Sensor Input Noise Threshold

but does not exceed the sensor input threshold, it is determined to be caused by a noise spike. That sample is not used

by the automatic recalibration routine. This feature can be disabled by setting the DIS_DIG_NOISE bit.

Bits 1-0 - CS1_BN_TH[1:0] - Controls the noise threshold for all capacitive touch sensor inputs, as shown in Table 5-37.

The threshold is proportional to the threshold setting.

TABLE 5-35:

SENSOR INPUT THRESHOLD REGISTERS

Addr

R/W

B5B4

B3B2

B1B0

Default

30h

R/W

Sensor Input 1

Threshold

-64

40h

31h

R/W

Sensor Input 2

Threshold

-64

40h

32h

R/W

Sensor Input 3

Threshold

-64

40h

TABLE 5-36:

SENSOR INPUT NOISE THRESHOLD REGISTER

Addr

R/W

B5B4

B3B2

B1B0

Default

38h

R/W

Sensor Input

Noise Threshold

CS_BN_TH

[1:0]

01h

TABLE 5-37:

CSX_BN_TH BIT DECODE

CS_BN_TH[1:0]

Percent Threshold Setting

25%

37.5% (default)

50%

62.5%

CAP1293 Folha de dados(PDF) 42 Page - Microchip Technology

CAP1293 Folha de dados(HTML) 42 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63

Folha de dados Download

Ligação URL