Datasheet

723
32142D–06/2013
ATUC64/128/256L3/4U
Figure 29-4. Resistive Touch Screen Pen Detect
The Resistive Touch Screen Pen Detect can be used to generate an ADCIFB interrupt request
or it can be used to trig a conversion, so that a position can be measured as soon as a contact is
detected.
The Pen Detect Mode generates two types of status signals, reported in the Status Register
(SR):
• The bit PENCNT is set when current flows and remains set until current stops.
• The bit NOCNT is set when no current flows and remains set until current flows.
Before a current change is reflected in the SR, the new status must be stable for the duration of
the debouncing time.
Both status conditions can generate an interrupt request if the corresponding bit in the Interrupt
Mask Register (IMR) is one. Refer to Section 29.6.11 on page 717.
X
P
X
M
Y
M
Y
P
Tr i s t at e
GND
Pullup
To the ADC
PenInterrupt
Debouncer
PENDBC
GND
Resistive
Touch Screen
Sequencer