ucb1200 NXP Semiconductors, ucb1200 Datasheet - Page 13

• Manufacturer Part Number: ucb1200
• Description: Advanced Modem/audio Analog Front-end
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Product specification
Advanced modem/audio analog front-end
UCB1200
TOUCH SCREEN MEASUREMENT MODES
The UCB1200 contains an on chip interface for a 4 wire resistive touch screen. This interface supports three modes of
touch screen measurements: position, pressure and plate resistance.
POSITION MEASUREMENT
Two position measurements are needed to determine the location of the pressed spot. First an X measurement, secondly
a Y measurement. The X plate is biased during the X position measurement of the X plate and the voltage on one or both
Y terminals (TSPY, TSMY) measured. The circuit can then be represented by a potentiometer, with the TSPY and/or
TSMY electrode being the ‘wiper’. The measured voltage on the TSPY/TSMY terminal is proportional to the X position
of the pressed spot of the touch screen.
Vposition
Vtscbias
tspx
tsmy
tspy
tsmx
Fig.8 Touch screen setup for position measurement.
In the Y position mode the X plate and Y plate terminals are interchanged, thus the Y plate is biased while the voltage
on the TSPX and/or TSMX terminal is measured.
1998 Jul 22
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