MAX1233 Datasheet, PDF (38/44 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
HOST-INITIATED
X- AND Y- SCREEN SCAN
STORE X- COORDINATES
IN X- REGISTER
YES
ARE THERE
UNREAD SCAN
RESULTS?
NO
SET
PENIRQ LOW
IS PENSTS
BIT = 1?
YES
GO TO
TOUCH-INITIATED
SCAN
(FIGURE 21)
NO
HOST WRITES
ADC CONTROL REGISTER
(PENSTS = ADSTS = 0)
POWER DOWN ADC
TURN ON DRIVERS: X+, X-
NO IS TOUCH-SCREEN
SETTLING DONE?
YES
POWER UP ADC
CONVERT Y- COORDINATES
SET BUSY LOW
START CLOCK
TURN ON DRIVERS: Y+, Y-
NO
IS DATA
AVERAGING DONE?
YES
STORE Y- COORDINATES IN
Y- REGISTER
POWER DOWN ADC
NO IS TOUCH-SCREEN
SETTLING DONE?
SET BUSY HIGH
YES
POWER UP ADC
CONVERT X- COORDINATES
TURN OFF CLOCK
RESET PENIRQ HIGH
DONE
NO
IS DATA
AVERAGING DONE?
YES
Figure 23. Host-Initiated X- and Y- Coordinate Screen Scan
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