MAX1233 Datasheet, PDF (36/44 Pages) Maxim Integrated Products – ±15kV ESD-Protected Touch-Screen Controllers Include DAC and Keypad Controller

±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
SCREEN
TOUCH
PENIRQ-INITIATED
X- AND Y- SCREEN SCAN
POWER DOWN ADC
YES
ARE THERE
UNREAD SCAN
RESULTS?
NO
SET
PENIRQ LOW
IS PENSTS
BIT = 1?
YES
START CLOCK
GO TO
NO HOST-INITIATED
SCAN
(FIGURE 23)
SET BUSY LOW
TURN ON DRIVERS: Y+, Y-
TURN ON DRIVERS: X+. X-
NO _{IS TOUCH-SCREEN}
SETTLING DONE?
YES
POWER UP ADC
CONVERT Y- COORDINATES
NO
IS DATA
AVERAGING DONE?
YES
STORE Y- COORDINATES IN
Y- REGISTER
NO
IS TOUCH-SCREEN
SETTLING DONE?
YES
POWER UP ADC
POWER DOWN
ADC
SET BUSY HIGH
TURN OFF CLOCK
CONVERT X- COORDINATES
RESET PENIRQ HIGH
NO
IS DATA
AVERAGING DONE?
YES
STORE X- COORDINATES
IN X- REGISTER
DONE
Figure 21. Touch-Initiated X- and Y- Coordinate Screen Scan
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