8 Channel Capacitive Touch Sensor with 2 LED Drivers
Datasheet
5.19
Sensor Input Noise Threshold Register
Table 5.33 Sensor Input Noise Threshold Register
B7 B6 B5 B4 B3
ADDR
R/W
REGISTER
B2
B1
B0
DEFAULT
Sensor Input
Noise Threshold
CS_BN_TH
[1:0]
38h
R/W
01h
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 re-calibration 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 5.34. The threshold is proportional to the threshold setting.
Table 5.34 CSx_BN_TH Bit Decode
CS_BN_TH[1:0]
1
0
PERCENT THRESHOLD SETTING
0
0
1
1
0
1
0
1
25%
37.5% (default)
50%
62.5%
5.20
Standby Channel Register
Table 5.35 Standby Channel Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
Standby
Channel
CS8_
STBY
CS7_
STBY
CS6_
STBY
CS5_
STBY
CS4_
STBY
CS3_
STBY
CS2_
STBY
CS1_
STBY
40h
R/W
00h
The Standby Channel register controls which (if any) capacitive touch sensor inputs are active during
Standby.
Bit 7 - CS8_STBY - Controls whether the CS8 channel is active in Standby.
‘0’ (default) - The CS8 channel not be sampled during Standby.
‘1’ - The CS8 channel will be sampled during Standby. It will use the Standby threshold setting, and
the standby averaging and sensitivity settings.
Bit 6 - CS7_STBY - Controls whether the CS7 channel is active in Standby.
Bit 5 - CS6_STBY - Controls whether the CS6 channel is active in Standby.
Bit 4 - CS5_STBY - Controls whether the CS5 channel is active in Standby.
Revision 1.32 (01-05-12)
SMSC CAP1128
DATA6S0HEET
SMSC [ SMSC CORPORATION ]
