WM9712CLGEFL/RV WOLFSON [Wolfson Microelectronics plc], WM9712CLGEFL/RV Datasheet - Page 45

• Manufacturer Part Number: WM9712CLGEFL/RV
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

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If the SLEN bit is set to ‘1’, then the touchpanel data appears on the AC-Link slot selected by the SLT
control bits, as shown below. The Slot 0 ‘tag’ bit corresponding to the selected time slot is asserted
whenever there is new data on that slot.
Table 30 Returning Touchpanel Data through an AC-Link Time Slot
TOUCHPANEL SETTLING TIME
For accurate touchpanel measurements, some settling time may be required between the switch
matrix applying a voltage across the touchpanel plate and the ADC sampling the signal. This time
delay function is built into the WM9712L and can be programmed as shown below.
Table 31 Touchpanel Settling Time Control (1)
Table 32 Touchpanel Settling Time Control (2)
The total time for co-ordinate or auxiliary measurements to complete is the delay time DEL, plus one
AC-Link frame (20.8s). For a pressure measurement, the time taken is DEL plus two AC-Link frames
(41.6s).
REGISTER
ADDRESS
76h
REGISTER
ADDRESS
76h
DEL
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
DELAY
(AC-LINK FRAMES)
BIT
7:4
BIT
3
2:0
No delay, switch matrix always on
128
160
192
224
256
288
16
32
48
64
96
LABEL
1
2
4
8
SLEN
SLT
LABEL
DEL
DEFAULT
0
110
DELAY
(TIME)
DEFAULT
0000
(1 frame)
1.33ms
2.67ms
3.33ms
4.67ms
5.33ms
20.8s
41.7s
83.3s
167s
333s
667s
1ms
2ms
4ms
6ms
DESCRIPTION
Slot Readback Enable
0: Disabled (readback through register only)
1: Enable (readback slot selected by SLT)
AC’97 Slot Selection for Touchpanel Data
000: Slot 5
001: Slot 6
…
101: Slot 10
110: Slot 11
111: RESERVED
DESCRIPTION
Touchpanel ADC Settling Time
PD, Rev 4.6, November 2011
WM9712L
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