AT32UC3L-EK Atmel, AT32UC3L-EK Datasheet - Page 611

• Manufacturer Part Number: AT32UC3L-EK
• Description: KIT EVAL AVR32 UC3 MCU
• Manufacturer: Atmel
• Type: MCUr

Specifications of AT32UC3L-EK

• Contents: *
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Core Sub-architecture: UC3L
• Kit Contents: Board
• Features: USB / Battery Powered, Board Controller / Bootloader
• Svhc: No SVHC (15-Dec-2010)
• Rohs Compliant: Yes
• Tool Type: Starter Kit
• Cpu Core: AVR 8
• Data Bus Width: 8 bit
• Processor Series: AT32
• Processor To Be Evaluated: AT32UC3L064
• Interface Type: USB, Capacitive Touch
• For Use With/related Products: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

26.7.5
32099F–11/2010
Pen Detect
If no contact is applied to the resistive touch screen films, any resistive touch screen conversion
result will be undefined as the film being measured is floating. This can be avoided by enabling
Pen Detect and only trigger resistive touch screen conversions when the Pen Contact
(PENCNT) status bit in the Status Register (SR) is one. Pen Detect is enabled by writing a one
to the Pen Detect (PENDET) bit in the Mode Register (MR).
When Pen Detect is enabled, the ADCIFB grounds the vertical panel by applying GND to X
X
will in this mode be tristated. Since there is no contact, no current is flowing and there is no
related power consumption. As soon as a contact occurs, GND will propagate to Y
down Y
A programmable debouncing filter can be used to filter out false pen detects because of noise.
The debouncing filter is programmable from one CLK_ADC period and up to 2
ods. The debouncer length is set by writing to the PENDBC field in MR.
Figure 26-4. 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):
Before a current change is reflected in the SR, the new status must be stable for the duration of
the debouncing time.
M
• 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.
and polarizes the horizontal panel by enabling pull-up on the pin connected to Y
P
X
Y
, allowing the contact to be registered by the ADCIFB.
X
Y
M
M
P
P
Tristate
GND
GND
Pullup
Touch Screen
Sequencer
Resistive
T o the ADC
AT32UC3L016/32/64
D ebouncer
PENDBC
15
Pen Int er r upt
CLK_ADC peri-
P
. The Y
M
by pulling
P
M
and
611
pin