AR1000_16 Datasheet, PDF (8/61 Pages) Microchip Technology – AR1000 Series Resistive Touch Screen Controller

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER
2.5 5-Wire Sensor
A 5-wire resistive touch sensor consists of a flex and
stable layer, electrically separated by spacer dots. The
touch position is determined by first applying a voltage
gradient across the stable layer in the X-axis direction
and using the flex layer to measure the axis touch posi-
tion voltage. The second step is applying a voltage gra-
dient across the stable layer in the Y-axis direction and
using the flex layer to measure the axis touch position
voltage.
The voltage is not directly applied to the edges of the
active layer, as it is for 4-wire and 8-wire sensors. The
voltage is applied to the corners of a 5-wire sensor.
FIGURE 2-3:
5-Wire Decoding
To measure the X-axis, the left edge of the layer is
driven with 0V (ground), using connections to the upper
left and lower left sensor corners. The right edge is
driven with +5 VDC, using connections to the upper
right and lower right sensor corners.
To measure the Y-axis, the top edge of the layer is
driven with 0V (ground), using connections to the upper
left and upper right sensor corners. The bottom edge is
driven with +5 VDC, using connections to the lower left
and lower right sensor corners.
The measured voltage at any position across a driven
axis is predictable. A touch moving in the direction of
the driven axis will yield a linearly changing voltage. A
touch moving perpendicular to the driven axis will yield
a relatively unchanging voltage (See Figure 2-3).
DS40001393C-page 8
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