MAX11800_1010 Datasheet, PDF (22/59 Pages) Maxim Integrated Products – Low-Power, Ultra-Small Resistive Touch-Screen Controllers with I2C/SPI Interface

Low-Power, Ultra-Small Resistive Touch-Screen
Controllers with I²C/SPI Interface
FAST PULLUP TOUCH DETECTION
DIGITAL WAVEFORM
(NOTE: INCREASED CURRENT IN PUR MODE DURING TOUCH)
DATA VALIDITY IS DETERMINED
(DATA IS TAGGED)
SCAN MODE
MEASUREMENT COMPLETE—
DATA IS KNOWN
PUR MODE
(OPTIONAL)
POWER ASSISTED PULLUP PERIOD (10Ω)
PUF MODE
PANEL IS ALLOWED TO RESETTLE BEFORE
DETERMINING DATA VALIDITY
TOUCH DETECT
IS THERE A TOUCH?
YES = LPM.
NO = TDM.
ANALOG WAVEFORM
V_DD
INITIAL INPUT VOLTAGE
DETERMINED BY LAST SCAN
ACTIVITY
FORCED FAST PULLUP USING
10Ω SWITCH
TIME
NORMAL TOUCH DETECTION
DIGITAL WAVEFORM
(NOTE: NO PUR PERIOD; ALLOW LONG PULLUP TIMES)
DATA VALIDITY IS DETERMINED
(DATA IS TAGGED)
TOUCH NOT PRESENT: TSC INPUT
REMAINS HIGH
TOUCH PRESENT:
TSC INPUT PULLED LOW
SCAN MODE
MEASUREMENT COMPLETE—
DATA IS KNOWN
PUF MODE
PANEL IS ALLOWED TO RESETTLE BEFORE DETERMINING DATA VALIDITY
(THROUGH 50kΩ/100kΩ PULLUP)
TOUCH DETECT
IS THERE A TOUCH?
YES = LPM.
NO = TDM.
ANALOG WAVEFORM
V_DD
INITIAL INPUT VOLTAGE
DETERMINED BY LAST SCAN
ACTIVITY
TOUCH NOT PRESENT:
TSC INPUT PULLED HIGH THROUGH 50kΩ/100kΩ PULLUP
TOUCH PRESENT:
TSC INPUT PULLED LOW BY PANEL
TIME
Figure 7. Touch-Detection Operations
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