Touch Operation - LG KS660 Service Manual

3. TECHNICAL BRIEF

3.15. Touch Operation

General description
The TSC2007 is a very low-power touch screen controller designed to work with power-sensitive,
handheld applications that are based on an advanced low-voltage processor. It works with a supply
voltage as low as 1.2V, which can be supplied by a single-cell battery. It contains a complete, ultra-low
power, 12-bit, analog-to-digital(A/D) resistive touch screen converter, including drivers and the control
logic to measure touch pressure.
In addition to these standard features, the TSC2007 offers preprocessing of the touch screen
measurements to reduce bus loading, thus reducing the consumption of host processor resources that
can then be redirected to more critical functions.
The TSC2007 supports an I
standard, fast, and high-speed. It offers programmable resolution of 8 or 12 bits to accommodate
different screen sizes and performance needs.
The TSC2007 is available in a 12-lead, (1.555 0.055mm) x (2.055 0.055mm), 3 x 4 array, wafer
chip-scale package (WCSP), and a 16-pin, TSSOP package. The TSC2007 is characterized for the
–40 C to +85 C industrial temperature range.
TOUCH SCREEN OPERATION
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 TSC2007 supports the resistive 4-wire configurations, as shown in Figure 20. The circuit determines
location in two coordinate pair dimensions, although a third dimension can be added for measuring
pressure.
LGE Internal Use Only
C serial bus and data transmission protocol in all three defined modes:
2
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