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775
32142D–06/2013
ATUC64/128/256L3/4U
Figure 31-3. CAT Matrix Connections
In order to use the autonomous QTouch detection capability, the user must first set up the
Autonomous Touch Pin Select Register (ATPINS) and Autonomous/DMA Touch Configuration
Registers (ATCFG0 through 3) with appropriate values. The module can then be enabled using
the Control Register (CTRL). After the module is enabled, the module will acquire data from the
autonomous QTouch sensor and use it to determine whether the sensor is activated. The
active/inactive status of the autonomous QTouch sensor is reported in the Status Register (SR),
and it is also possible to configure the CAT to generate an interrupt whenever the status
changes. The module will continue acquiring autonomous QTouch sensor data and updating
autonomous QTouch status until the module is disabled or reset.
In order to use the DMATouch capability, it is first necessary to set up the pin mode registers
(PINMODE0, PINMODE1, and PINMODE2) so that the desired pins are specified as DMA-
Touch. The Autonomous/DMA Touch Configuration Registers (ATCFG0 through 3) must also be
configured with appropriate values. One channel of the Peripheral DMA Controller must be set
up to transfer state words from a block of memory to the DMATSW register, and another chan-
nel must be set up to transfer state words from the DMATSR register back to the same block of
memory. The module can then be enabled using the CTRL register. After the module is enabled,
the module will acquire count values from each DMATouch sensor. Once the module has
acquired a count value for a sensor, it will use a handshake interface to signal the Peripheral
DMA controller to transfer a state word to the DMATSW register. The module will use the count
value to update the state word, and then the updated state word will be transferred to the
DMATSR register. Another handshake interface will signal the Peripheral DMA controller to
transfer the contents of the DMATSR register back to memory. The status of the DMATouch
sensors can be determined at any time by reading the DMATouch Sensor Status Register
(DMATSS).
AVR32 Chip
Cs0 (Sense Capacitor)
X3
YK0
QMatrix Sensor Array
X6
X7
X2
Y0
YK1
Y1
Cs1 (Sense Capacitor)
SMP
Rsmp1
Rsmp0
VDIVEN
DIS
Rdis
ACREFN
Ra
Rb
NOTE: If the CAT internal
current sources will be enabled,
the SMP signal and Rsmp
resistors should NOT be included
in the design. If the CAT internal
current sources will NOT be
enabled, the DIS signal and Rdis
resistor should NOT be included
in the design.