Datasheet

WVGA/LCD EI3 Extender Board Manual 1-5
Using WVGA/LCD EI3 Extender Board
LCD Touch Controller (AD7879)
The WVGA/LCD EI3 Extender Board is equipped with an Analog
Devices resistive touch controller (AD7879). The AD7879 controller is
connected to the LCD touch screen via four pins (X+, X-, Y+, Y-). You
can access the controller via the SPI of the processor. The controller gen-
erates an interrupt request for the processor whenever the user touches the
LCD. The processor uses the SPI to read the appropriate registers on the
controller.
An interrupt signal from the AD7879 controller is connected to a GPIO
signal of the processor. The GPIO signal is configured via a software
switch. The SPI is used for communications between the controller and
processor; the SPI signals are configured via software as well. Refer to
“AD7879 PENIRQ Signal” and “AD7879 SPI Chip Select” on page 2-14
for details.
For more information about the AD7879 touch controller, go to www.ana-
log.com
and search for AD7879.
An example program demonstrating capabilities of the touch controller is
available by installing the product BSP.
Capacitive Touch Controller (AD7147)
The WVGA/LCD EI3 Extender Board is equipped with an Analog
Devices CapTouch
®
programmable controller (AD7147) for applications
implementing push buttons and scroll wheels. The four push button sen-
sors and one scroll wheel are located on the top side of the extender’s
printed circuit board (PCB).
The AD7147 controller generates an interrupt request for the processor
whenever a user touches the push button or the scroll wheel. The two-wire
interface (TWI) is used for communications between the controller and