Datasheet

8 Channel Capacitive Touch Sensor with 8 LED Drivers
Datasheet
SMSC CAP1188 53 Revision 1.32 (01-05-12)
DATASHEET
Bits 3 - 2 - SAMP_TIME[1:0] - Determines the time to take a single sample as shown in Table 5.19.
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.
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.
1 0 1 32
1 1 0 64
1 1 1 128
Table 5.19 SAMP_TIME Bit Decode
SAMP_TIME[1:0]
SAMPLE TIME1 0
0 0 320us
0 1 640us
1 0 1.28ms (default)
1 1 2.56ms
Table 5.20 CYCLE_TIME Bit Decode
CYCLE_TIME[1:0]
OVERALL CYCLE TIME1 0
0 0 35ms
0 1 70ms (default)
1 0 105ms
1 1 140ms
Table 5.18 AVG Bit Decode (continued)
AVG[2:0]
NUMBER OF SAMPLES TAKEN
PER MEASUREMENT2 1 0