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Conversion Controlled by TSC2005 Initiated by Host (TSMode 2)
t
COORDINATE
+
OH1
f
OSC
)2 @
ǒ
t
PVS
)t
PRE
)t
SNS
)
OH
DLY1
f
OSC
Ǔ
)2 @
ǒ
N @
ǒ(
B)2
)
@
f
OSC
f
ADC
)OH
CONV
Ǔ
@
ǒ
1
f
OSC
Ǔ
)
ǒ
L
PPRO
f
OSC
Ǔ
Ǔ
(7)
Detecting
Touch
PINTDAV Programmed:
As ,
CFR2,D[15:14]=10
PENIRQ
As ,
CFR2,D[15:14]=11or01
DAV
As and ,
CFR2,D[15:14]=00
PENIRQ DAV
Programmed
for
Host-
Controlled
Mode
(PSM=0)
CS
Deactivated
P ograr mm d
for
X-Y
ScanMode
e
Reading
X-Data
Register
WaitingforHostto
WriteInto
ControlByte1D[6:3]
Sample,Conversion,
andPreprocessingfor
YCoordinate
TouchisStillHere
Reading
Y-Data
Register
CS
Deactivated
CS
Deactivated
Detecting
Touch
TouchisDetected
TouchisDetected
Sample,Conversion,
andPreprocessingfor
XCoordinate
Detecting
Touch
Sample,Conversion,
andPreprocessingfor
YCoordinate
Detecting
Touch
t
COORDINATE
TSC2005
SBAS379C – DECEMBER 2006 – REVISED MARCH 2008
In TSMode 2, the TSC2005 detects when the touch panel is touched and causes the internal Pen-Touch signal
to activate, which lowers the PINTDAV output if it is programmed as PENIRQ. The host recognizes the interrupt
request, and then writes to the A/D Converter Control register to select one of the two touch screen scan
functions:
1. X-Y-Z Scan (converter function select bits C[3:0] = Control Byte 1 D[6:3] = 0000); or
2. X-Y Scan (converter function select bits C[3:0] = Control Byte 1 D[6:3] = 0001).
See Table 7 for more information on the converter function select bits.
The conversion process then as shown in Figure 34 ; see previous sections for more details.
The main difference between this mode and the previous mode is that the host, not the TSC2005, decides when
the touch screen scan begins.
The time needed to convert both X and Y coordinates under host control (not including the time needed to send
the command over the SPI bus) is given by:
Figure 34. Example of an X and Y Coordinate Touch Screen Scan using TSMode 2
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