WM9712CLGEFL/RV WOLFSON [Wolfson Microelectronics plc], WM9712CLGEFL/RV Datasheet - Page 42

• Manufacturer Part Number: WM9712CLGEFL/RV
• Manufacturer: WOLFSON [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)
REGISTER
ADDRESS
78h
REGISTER
ADDRESS
78h
BIT
12
0:5
8
BIT
15:14
13
RPU
LABEL
45W
PIL
LABEL
PRP
RPR
DEFAULT
0 (4-wire)
000001
(64k)
0 (200A)
DEFAULT
00
0
DESCRIPTION
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
DESCRIPTION
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
= 200A
= 400A
PU
PU
/1 = TYP 64k (most sensitive)
/2 = TYP 32k
PU
/ binary value of RPU)
PD, Rev 4.6, November 2011
PU
specification)
Production Data
42