Datasheet

8 Channel Capacitive Touch Sensor with 8 LED Drivers
Datasheet
SMSC CAP1188 61 Revision 1.32 (01-05-12)
DATASHEET
5.19 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 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.
5.20 Standby Channel Register
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.
Table 5.33 Sensor Input Noise Threshold Register
ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT
38h R/W
Sensor Input
Noise Threshold
CS_BN_TH
[1:0]
01h
Table 5.34 CSx_BN_TH Bit Decode
CS_BN_TH[1:0]
PERCENT THRESHOLD SETTING1 0
0 0 25%
0 1 37.5% (default)
1 0 50%
1 1 62.5%
Table 5.35 Standby Channel Register
ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT
40h R/W
Standby
Channel
CS8_
STBY
CS7_
STBY
CS6_
STBY
CS5_
STBY
CS4_
STBY
CS3_
STBY
CS2_
STBY
CS1_
STBY
00h