Atmel Evaluation Kit AT91SAM9X35-EK AT91SAM9X35-EK Data Sheet
Product codes
AT91SAM9X35-EK
939
SAM9X35 [DATASHEET]
11055E–ATARM–10-Mar-2014
Figure 42-11. Touchscreen Pen Detect
The Touchscreen Pen Detect can be used to generate an ADC interrupt to wake up the system. The Pen Detect
generates two types of status, reported in the “ADC Interrupt Status Register”:
generates two types of status, reported in the “ADC Interrupt Status Register”:
The PEN bit is set as soon as a contact exceeds the debouncing time as defined by PENDBC and remains set
until ADC_SR is read.
until ADC_SR is read.
The NOPEN bit is set as soon as no current flows for a time over the debouncing time as defined by PENDBC and
remains set until ADC_SR is read.
remains set until ADC_SR is read.
Both bits are automatically cleared as soon as the Status Register (ADC_SR) is read, and can generate an interrupt by
writing the “ADC Interrupt Enable Register”.
writing the “ADC Interrupt Enable Register”.
Moreover, the rising of either one of them clears the other, they cannot be set at the same time.
The PENS bit of the ADC_SR indicates the current status of the pen contact.
X+/U
L
X-/U
R
L
R
VDDANA
Y+/L
L
VDDANA
GND
GND
To the ADC
VDDANA
GND
Y-/SENSE
GND
GND
Pen Interrupt
Debouncer
PENDBC
0
1
2
3
4