Phytec 1337.1, Hardware Manual

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Display Adapter LCD-014-x / LCD-017-x
24
©
PHYTEC Messtechnik GmbH 2011 L-758e_1
7.1 Controlling Touch with the phyBASE
Two touch screen controllers are available on the phyCARD Carrier
Board. The choice which controller is chosen to handle the signals
from the touch screen is pegged to the audio standard supported by the
phyCARD.
phyCARDs supporting the AC'97 standard use the Wolfson
WM9712L at U1. Its dual functionality for audio and touch AC97
codec allows connecting 4- and 5-wire touch panels. The touch screen
data is then available at the AC'97 interface.
phyCARDs delivering HDA compliant audio signals use the Cirrus
Logic HDA Audio CODEC at U17 together with the STMPE811
touch panel controller at U28, which is suitable for 4-wire touch
panels only. The touch screen data is then available at the I²C
interface.
Switches 1 and 2 of DIP-Switch S3 select which controller is used to
process the touch panel signals. The different configurations are
shown in
Table 7
.
Button Setting Description
S3_1/
S3_2
0/0
0/1
1/0
1/1
Auto Detection: based on the high level of the
HDA_SEL/AC_INT signal generated on the
phyCARD the Wolfson audio/touch contrl. (U1) is
selected to process the signals from a touch screen and
the AC'97 compliant audio signals.
Wolfson audio/touch contrl. (U1) is selected to process
the signals from a touch screen and the AC'97 compliant
audio signals.
Analog Devices audio contrl. (U17) selected for audio
and STMPE811 touch contrl. (U28) for touch.
not used
Table 7: Selection of the touch screen controller