Datasheet

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X+
Y+
X-
Y-
AuxilaryInput
AGND
AGND
TSC2004
SNSGND
DGND
1 Fm
1.6VDC
0.1 Fm
Touch
Screen
GPIO
GPIO
SDA
SCL
Host
Processor
PINTDAV
RESET
SDA
SCL
SNSVDD
VREF
I/OVDD
AUX
SNSGND
AGND
SUBGND
DGND
1 Fm 0.1 Fm
1 Fm 0.1 Fm
( isoptional;
softwareimplementation
pollingoftheStatus
registerispossible)
PINTDAV
AD1 AD0
1.2kW
1.6VDC
1.2kW
TOUCH SCREEN OPERATION
4-WIRE TOUCH SCREEN COORDINATE PAIR MEASUREMENT
ConductiveBar
InsulatingMaterial(Glass)
Silver
Ink
TransparentConductor(ITO)
BottomSide
Transparent
Conductor(ITO)
TopSide
X+
X-
Y+
Y-
ITO=IndiumTinOxide
TSC2004
SBAS408E – JUNE 2007 – REVISED MARCH 2008
Figure 24. Typical Circuit Configuration
A resistive touch screen operates by applying a voltage across a resistor network and measuring the change in
resistance at a given point on the matrix where the screen is touched by an input (stylus, pen, or finger). The
change in the resistance ratio marks the location on the touch screen.
The TSC2004 supports the resistive 4-wire configurations, as shown in Figure 25 . The circuit determines location
in two coordinate pair dimensions, although a third dimension can be added for measuring pressure.
A 4-wire touch screen is typically constructed as shown in Figure 25 . It consists of two transparent resistive
layers separated by insulating spacers.
Figure 25. 4-Wire Touch Screen Construction
The 4-wire touch screen panel works by applying a voltage across the vertical or horizontal resistive network.
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