8 Channel Capacitive Touch Sensor with 8 LED Drivers
Datasheet
5.10 Averaging and Sampling Configuration Register
Table 5.15 Averaging and Sampling Configuration Register
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
Averaging and
Sampling Config
SAMP_
TIME
CYCLE_TIME
[1:0]
24h
R/W
AVG[2:0]
1Dh
The Averaging and Sampling Configuration register controls the number of samples taken and the total
sensor cycle time for all active sensors while the device is functioning normally.
Bits 5 - 3 - AVG[2:0] - Determines the number of samples that are taken for all active channels during
the sensor cycle as shown in Table 5.16. All samples are taken consecutively on the same channel
before the next channel is sampled and the result is averaged over the number of samples measured
before updating the measured results.
For example, if CS1, CS2, and CS3 are sampled during the sensor cycle, and the AVG[2:0] bits are
set to take 4 samples per channel, then the full sensor cycle will be: CS1, CS1, CS1, CS1, CS2, CS2,
CS2, CS2, CS3, CS3, CS3, CS3.
Table 5.16 AVG Bit Decode
AVG[2:0]
NUMBER OF SAMPLES TAKEN
2
1
0
PER MEASUREMENT
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
1
2
4
8 (default)
16
32
64
128
Bit 2 - SAMP_TIME - Determines the time to take a single sample.
‘0’ - The sampling time is ~2.56ms.
‘1’ (default) - The sampling time is ~1.28ms.
Bits 1 - 0 - CYCLE_TIME[1:0] - Determines the overall cycle time for all measured channels during
normal operation as shown in Table 5.17. 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.
SMSC CAP1088
Revision 1.1 (08-05-09)
DATA4S3HEET
SMSC [ SMSC CORPORATION ]
