AT32UC3L-EK Atmel, AT32UC3L-EK Datasheet - Page 665

• 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

28.6.4
28.6.5
32099F–11/2010
Autonomous QTouch
Peripheral Events
For autonomous QTouch, a complete detection algorithm is implemented within the CAT mod-
ule. The additional parameters needed to control the autonomous QTouch detection algorithm
must be specified by the user in the ATCFG2 and ATCFG3 registers.
Autonomous QTouch sensitivity and out-of-touch sensitivity can be adjusted with the SENSE
and OUTSENS fields, respectively, in ATCFG2. Each field accepts values from one to 255
where 255 is the least sensitive setting. The value in the OUTSENS field should be smaller than
the value in the SENSE field.
To avoid false positives a detect integration filtering technique can be used. The number of suc-
cessive detects required is specified in the FILTER field of the ATCFG2 register.
To compensate for changes in capacitance the CAT can recalibrate the autonomous QTouch
sensor periodically. The timing of this calibration is done with the NDRIFT and PDRIFT fields in
the Configuration register, ATCFG3. It is recommended that the PDRIFT value is smaller than
the NDRIFT value.
The autonomous QTouch sensor will also recalibrate if the count value goes too far positive
beyond a threshold. This positive recalibration threshold is specified by the PTHR field in the
ATCFG3 register.
The following block diagram shows the sequence of acquisition and processing operations used
by the CAT module. The AISR written bit is internal and not visible in the user interface.
The peripheral event from the AST is used to trigger one iteration of autonomous touch detec-
tion when the chip is in a sleep mode that has disabled CLK_CAT. When CLK_CAT is disabled
and the peripheral event from the AST becomes active, a request will automatically be made to
enable CLK_CAT. When CLK_CAT is enabled, the CAT will perform one iteration of the autono-
mous touch detection algorithm. After this, the CLK_CAT will be disabled, and the CAT module
will remain in a frozen state until the next AST peripheral event.
The eight peripheral events from the analog comparators are automatically used by the CAT
when performing QMatrix acquisition. The CAT will automatically use the negative peripheral
events from the AC Interface on every Y pin in QMatrix mode. When QMatrix acquisition is used
the analog comparator corresponding to the selected Y pins must be enabled and converting
continuously, using the Y pin as the positive reference and the ACREFN as negative reference.
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