Datasheet

21
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TSC2000
SBAS257
FIGURE 10. X- and Y-Coordinate Touch Screen Scan, Initiated by Host.
Screen
Touch
Issue Interrupt
PENIRQ
Go to Host-Controlled
Conversion
Touch Screen Scan
X and Y
Host Initiated
Done
Done
No
No
Yes
Yes
No
No
Yes
Is Data
Averaging Done
Is Screen
Touched
Is Panel Voltage
Stabilization Done
Turn On Drivers: Y+, Y–
Start Clock
Reset PENIRQ
Store Y-Coordinates in
Y-Register
Power Down A/D Converter
Power Up A/D Converter
Reset PENIRQ and
Scan Trigger
Turn Off Clock
Convert Y-Coordinates
Is PSM = 1
Yes
No
Is Screen
Touched
No
Yes
Is Panel Voltage
Stabilization Done
Convert X-Coordinates
Turn On Drivers: X+, X–
Power Up A/D Converter
No
Yes
Is Data
Averaging Done
Store X-Coordinates
in X-Register
Power Down A/D Converter
Turn Off Clock
Issue Data Available
Done
Host Writes A/D
Converter
Control Register
Conversion Controlled by TSC2000 Initiated By
Host Responding to
PENIRQ
In this mode, the TSC2000 will detect when the touch panel is
touched and cause the
PENIRQ line to go LOW. The host will
recognize the interrupt request, and then write to the A/D
Converter Control register to select one of the touch screen
scan functions. The conversion process then proceeds as
described above, and as outlined in Figures 10 through 14.
The main difference between this mode and the previous
mode is that the host, not the TSC2000, decides when the
touch screen scan begins.