wm9705seft-v Wolfson Microelectronics plc, wm9705seft-v Datasheet - Page 47

• Manufacturer Part Number: wm9705seft-v
• Description: Multimedia Ac?97 Codec With Integrated Touch Screen Controller
• Manufacturer: Wolfson Microelectronics plc

WM9705
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ADC Mode
Pen Data
SYNC
ADC Mode
ADC Mode
SYNC
SYNC
Pen Data
Pen Data
CTC = 1, CC=00, Coord = 1, ADR = 000 ( 0x76 = 0x0C00 ) = X and Y Measurement every 512 AC Link Frames
CTC = 1, CC=01, Coord = 1, ADR = 100 ( 0x76 = 0x4C01 ) = X, Y and BMON Measurement every 256 AC Link Frames
Different types of continuous conversion with delay set to 0 (1 frames)
DELAY
CTC = 1, CC=11, Coord = 0, ADR = 001 ( 0x76 = 0x1700 ) = X Measurement every 64 AC Link Frames
Conversion 1
Figure 23 Control of ADC Conversions : Continuous Method
Table 27 Programmable Screen Drive Delay
In order to allow time for the plates to charge to a steady voltage when the screen drive switches
are closed, a programmable delay may be applied which delays the sampling of the appropriate
plate voltage by the ADC. This delay is at least one frame (1/48kHz) in duration, but may be
increased by writing a value to the DEL[3-0] bits in register 76h. These set delays as follows:
Note that code 15 is used as a special mode, where the plates are driven permanently on, the
switch matrix setting controlled by the value selected by ADR[2-0]. Thus the plates may be
permanently set to drive X screen, Y screen, pressure configuration, or the auxiliary input channel
permanently connected to the ADC input. For further information please see the section on
Auxiliary Conversions.
DELAY FUNCTION
0
1
2
3
4
5
6
7
DEL[3-0]
DELAY
DELAY
CONVERT
Conversion 1
Conversion 1
CONVERT
CONVERT
DELAY
Conversion 1 - X
result available
1
2
4
8
16
32
48
64
(FRAMES)
DELAY
CONVERT
Conversion 1 - X
result available
DELAY
CONVERT
Conversion 1 result available
DELAY
Conversion 1 - Y
result available
256 Frames
CONVERT
20.8
41.7
83.3
166.7
333.3
666.7
1000
1333
512 Frames
64 Frames
DELAY
(uS)
Conversion 1 - Y
result available
8
9
10
11
12
13
14
15
Conversion 2
DELAY
Conversion 2
DELAY
DEL[3-0]
Conversion 1 - BMON
result available
CONVERT
CONVERT
DELAY
Conversion 1
96
128
160
192
224
256
288
infinite
CONVERT
Conversion 2 result available
DELAY
(FRAMES)
Conversion 2 - X
result available
DELAY
CONVERT
DELAY
Conversion 2 - X
result available
CONVERT
Conversion 2 - Y
PD Rev 4.5 July 2008
result available
1666
2000
2333
2666
3000
3333
3666
infinite
DELAY
Production Data
(uS)
DELAY
Conversion 2 - Y
result available
256 Frames
CONVERT
47
Conversion 2 - BMON
result available