MAX1233_08 Datasheet, PDF (37/44 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, Y, AND Z SCREEN SCAN
STORE X- COORDINATES
IN X- REGISTER
YES
ARE THERE
UNREAD SCAN
RESULTS?
NO
SET
PENIRQ LOW
IS PENSTS
BIT = 1?
YES
START CLOCK
GO TO
HOST-INITIATED
SCAN
(FIGURE 24)
SET BUSY LOW
TURN ON DRIVERS: Y+, Y-
NO IS TOUCH-SCREEN
SETTLING DONE?
YES
POWER UP ADC
POWER DOWN ADC
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
POWER DOWN ADC
TURN ON DRIVERS: Y+, X-
CONVERT X- COORDINATES
NO
IS DATA
AVERAGING DONE?
NO
IS TOUCH-SCREEN
SETTLING DONE?
YES
POWER UP ADC
CONVERT Z₁- COORDINATES
NO
IS DATA
AVERAGING DONE?
YES
STORE Z₁- COORDINATES
IN Z₁- REGISTER
CONVERT Z₂ COORDINATES
NO
IS DATA
AVERAGING DONE?
YES
STORE Z₂- COORDINATES
IN Z₂- REGISTER
POWER UP ADC
SET BUSY HIGH
TURN OFF CLOCK
RESET PENIRQ HIGH
DONE
Figure 22. Touch-Initiated X- , Y-, and Z- Coordinate Screen Scan
______________________________________________________________________________________ 37