WM8948ECSSLASHR datasheet(96/189 Pages) WOLFSON

номер детали	WM8948ECS/R

подробное описание детали	Stereo Low-Power CODEC with Video Buffer and Touch Panel Controller

PDF	189 Pages

Scroll/Zoom	100%

производитель	WOLFSON [Wolfson Microelectronics plc]

домашняя страница	http://www.wolfsonmicro.com

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WM8948

Production Data

PD, May 2011, Rev 4.1

WM8948

GND

LDOVDD

AUX

ADC

X position

Figure 35 X-axis Touch Panel Measurement

Y-axis measurement is performed by applying a potential difference between the Top and Bottom

sides of the touch panel. When contact is made between the two sheets, the voltage present on the

Left or Right connections is a measure of the Y-axis position of the contact. The configuration is

illustrated in Figure 36.

WM8948

GND

LDOVDD

AUX

ADC

Y position

Figure 36 Y-axis Touch Panel Measurement

‘Pen Down’ detection uses a zero-power comparator with an internal, programmable pull-up resistor.

When the touch panel is not being touched, no current flows between the touch panel sheets, and

the comparator output is low. When the touch panel is touched, current flows through the panel and

through the pull-up resistor, and the comparator output goes high. The sensitivity of the circuit can be

adjusted using different values of pull-up resistor; a large pull-up resistance leads to the most

sensitive response. The configuration is illustrated in Figure 37.

WM8948

GND

LDOVDD

RPU

zero power

comparator

PEN_DOWN

Figure 37 Pen-Down Touch Panel Detection

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