SX8650 Datasheet, PDF (28/56 Pages) Semtech Corporation – World’s Lowest Power & Smallest Footprint 4-wire Resistive Touchscreen Controller with 15kV ESD

SX8650
World’s Lowest Power & Smallest Footprint 4-wire
Resistive Touchscreen Controller with 15kV ESD
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
For FILT=2 the averaging is done on five samples
.
∑ ^{ADC 1 ⋅ s sn,sn-1,....,sn-4}
4
n−i
c_n
5 _i=0
Figure 25. data processing, FILT = 2
I2C
The FILT=3 will re-arrange seven samples out of the ADC in an ascending order and average the three center samples.
Figure 26 shows an example of the ordering and averaging.
.
sort
s_n,s_n-1,....,s_n-6
ADC
max
s_n
s_n-3
s_{n-2 = an-2}
s_{n-4 = an-1}
s_{n-5 = an}
s_n-1
s_n-6
min
∑ ^{1 ⋅ 2 an − i}
c_n
3 _i=0
Figure 26. data processing, FILT = 3
I2C
ACS Revision V2.15/October 2009
©2009 Semtech Corp.
Page 27
www.semtech.com