wm9712l Wolfson Microelectronics plc, wm9712l Datasheet - Page 42

• Manufacturer Part Number: wm9712l
• Description: Ac?97 Audio And Touchpanel Codec
• Manufacturer: Wolfson Microelectronics plc

WM9712L
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CONTROLLING THE TOUCHPANEL DIGITISER
All touchpanel functions are accessed and controlled through the AC-Link interface.
PHYSICAL CHARACTERISTICS
The physical characteristics of the touchpanel interface are controlled through register 78, as shown
below.
Table 25 Touchpanel Digitiser Control (Physical Characteristics)
POWER MANAGEMENT
To save power, the touchpanel digitiser and the pen-down detector can be independently disabled
when they are not used. The power consumption of the pen-down detector is normally negligible,
except when the pen is down.
The state of the digitiser and pen down detector is controlled by the following bits.
Table 26 Touchpanel Digitiser Control (Power Management)
78h
78h
REGISTER
REGISTER
ADDRESS
ADDRESS
12
0:5
8
15:14
13
BIT
BIT
45W
RPU
PIL
LABEL
PRP
RPR
LABEL
0 (4-wire)
000001
(64kΩ)
0 (200µA)
DEFAULT
00
0
DEFAULT
Touchpanel Type Selection
0: 4-wire
1: 5-wire
Internal Pull-up resistor for Pen Detection
000000: RESERVED (do not use this setting)
000001: R
000010: R
… (pull-up = R
(Refer to page 9 for R
Current used for pressure measurement
0: I
1: I
Pen ADC/AUX ADC enable
00 – Pen digitiser off, pen detect off, no
wake-up on pen down (default)
01 – Pen digitiser powered off, pen detect
enabled, touchpanel digitiser wakes up
(changes to state 11) on pen-down
10 – Pen digitiser off, pen detect enabled,
no wake-up on pen down
11 – Pen digitiser and pen detect enabled
Wake-up on pen-down mode
0: Wake-up the AC-Link only (hold
SDATAIN high until controller sends warm
reset or cold reset)
1: Wake-up the WM9712L without waiting
for a reset signal from the controller
P
P
= 200µA
= 400µA
PU
PU
/1 = TYP 64kΩ (most sensitive)
/2 = TYP 32kΩ
PU
DESCRIPTION
DESCRIPTION
/ binary value of RPU)
PU
PD Rev 4.5 August 2006
specification)
Production Data
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