MAX11803 Maxim Integrated Products, MAX11803 Datasheet - Page 22

• Manufacturer Part Number: MAX11803
• Description: (MAX11800 - MAX11803) Ultra-Small Resistive Touch-Screen Controllers
• Manufacturer: Maxim Integrated Products

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Low-Power, Ultra-Small Resistive Touch-Screen
Controllers with I
Figure 7. Touch-Detection Operations
22
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V
V
DD
DD
FAST PULLUP TOUCH DETECTION
DIGITAL WAVEFORM
ANALOG WAVEFORM
NORMAL TOUCH DETECTION
DIGITAL WAVEFORM
ANALOG WAVEFORM
MEASUREMENT COMPLETE—
MEASUREMENT COMPLETE—
DETERMINED BY LAST SCAN
DETERMINED BY LAST SCAN
INITIAL INPUT VOLTAGE
INITIAL INPUT VOLTAGE
DATA IS KNOWN
DATA IS KNOWN
SCAN MODE
SCAN MODE
ACTIVITY
ACTIVITY
POWER ASSISTED PULLUP PERIOD (10Ω)
(NOTE: NO PUR PERIOD; ALLOW LONG PULLUP TIMES)
PANEL IS ALLOWED TO RESETTLE BEFORE DETERMINING DATA VALIDITY
(NOTE: INCREASED CURRENT IN PUR MODE DURING TOUCH)
FORCED FAST PULLUP USING
10Ω SWITCH
2
(OPTIONAL)
PUR MODE
C/SPI Interface
(THROUGH 50kΩ/100kΩ PULLUP)
PUF MODE
TOUCH NOT PRESENT:
TSC INPUT PULLED HIGH THROUGH 50kΩ/100kΩ PULLUP
TIME
TIME
TOUCH PRESENT:
TSC INPUT PULLED LOW BY PANEL
DATA VALIDITY IS DETERMINED
DATA VALIDITY IS DETERMINED
PANEL IS ALLOWED TO RESETTLE BEFORE
(DATA IS TAGGED)
(DATA IS TAGGED)
DETERMINING DATA VALIDITY
PUF MODE
TOUCH NOT PRESENT: TSC INPUT
REMAINS HIGH
TOUCH PRESENT:
TSC INPUT PULLED LOW
IS THERE A TOUCH?
IS THERE A TOUCH?
TOUCH DETECT
TOUCH DETECT
YES = LPM.
YES = LPM.
NO = TDM.
NO = TDM.