3 Channel Capacitive Touch Sensor with 3 LED Drivers
Datasheet
Table 5.19 SAMP_TIME Bit Decode (continued)
SAMP_TIME[1:0]
1
0
SAMPLE TIME
1
1
2.56ms
Bits 1 - 0 - CYCLE_TIME[1:0] - Determines the overall cycle time for all measured channels during
normal operation as shown in Table 5.20. All measured channels are sampled at the beginning of the
cycle time. If additional time is remaining, then the device is placed into a lower power state for the
remaining duration of the cycle.
Table 5.20 CYCLE_TIME Bit Decode
CYCLE_TIME[1:0]
1
0
OVERALL CYCLE TIME
0
0
1
1
0
1
0
1
35ms
70ms (default)
105ms
140ms
APPLICATION NOTE: The programmed cycle time is only maintained if the total averaging time for all samples is
less than the programmed cycle. The AVG[2:0] bits will take priority so that if more samples
are required than would normally be allowed during the cycle time, the cycle time will be
extended as necessary to accommodate the number of samples to be measured.
5.11
Calibration Activate Register
Table 5.21 Calibration Activate Register
ADDR
26h
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
Calibration
Activate
CS3_
CAL
CS2_
CAL
CS1_
CAL
R/W
-
-
-
00h
The Calibration Activate register forces the respective sensor inputs to be re-calibrated affecting both
the analog and digital blocks. During the re-calibration routine, the sensor inputs will not detect a press
for up to 600ms and the Sensor Input Base Count register values will be invalid. During this time, any
press on the corresponding sensor pads will invalidate the re-calibration. When finished, the CALX[9:0]
bits will be updated (see Section 5.39).
When the corresponding bit is set, the device will perform the calibration and the bit will be
automatically cleared once the re-calibration routine has finished.
Bit 2 - CS3_CAL - When set, the CS3 input is re-calibrated. This bit is automatically cleared once the
sensor input has been re-calibrated successfully.
Bit 1 - CS2_CAL - When set, the CS2 input is re-calibrated. This bit is automatically cleared once the
sensor input has been re-calibrated successfully.
SMSC CAP1133
Revision 1.32 (01-05-12)
DATA3S7HEET
SMSC [ SMSC CORPORATION ]
