Datasheet

GND
TEMP1 TEMP2
V
DD
PenTouch
X+
Y+
Y-
HighwhentheX+orY+
driverison,orwhenany
sensorconnection/short-
circuittestsareactivated.
GND
ON
Sense
Viasgotosystemanaloggroundplane.
GND
Highwhen
theX+orY+
driverison.
Control
Logic
R
IRQ
VDD/REF
PENIRQ
Connectto
AnalogSupply
Preprocessing
7Acquired
Data
7
7m asue rementsinput
intotemporaryarray
Sortby
descendingorder
7
Averagingoutp tu
fromwindowof3
3
TSC2008
SBAS406B – JUNE 2008 – REVISED MARCH 2009 .......................................................................................................................................................... www.ti.com
Figure 27. Example of a Pen-Touch Induced Interrupt via the PENIRQ Pin
The TSC2008 has a fixed combined MAV filter (median value filter and averaging filter).
MAV Filter
If the acquired signal source is noisy because of the digital switching circuit, it may necessary to evaluate the
data without noise. In this case, the median value filter operation helps remove the noise. The array of seven
converted results is sorted first. The middle three values are then averaged to produce the output value of the
MAV filter.
The MAV filter is applied to all measurements for all analog inputs including the touch screen inputs, temperature
measurements TEMP1 and TEMP2, and auxiliary input AUX. To shorten the conversion time, the MAV filter may
be bypassed though the setup command; see Table 2 and Table 4 .
Figure 28. MAV Filter Operation (Patent Pending)
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Product Folder Link(s): TSC2008