AT32UC3L064-D3HES ATMEL [ATMEL Corporation], AT32UC3L064-D3HES Datasheet - Page 657

• Manufacturer Part Number: AT32UC3L064-D3HES
• Manufacturer: ATMEL [ATMEL Corporation]

28.5.4
28.5.5
28.5.6
28.5.7
28.6
28.6.1
32099D–06/2010
Functional Description
Peripheral Events
Peripheral Direct Memory Access
Analog Comparators
Debug Operation
Acquisition Types
The CAT module receives nine peripheral events, one from the AST and the remaining eight
from on-chip analog comparators. These peripheral events are connected via the Peripheral
Event System. Refer to the Peripheral Event System chapter for additional details.
The CAT module provides handshake capability for a Peripheral DMA Controller. One hand-
shake controls transfers from the Acquired Count Register (ACOUNT) to memory. A second
handshake requests burst lengths for each (X,Y) pair to the Matrix Burst Length Register
(MBLEN) when using the QMatrix acquisition method. The Peripheral DMA Controller must be
configured properly and enabled in order to perform direct memory access transfers to/from the
CAT module.
When the CAT module is performing QMatrix acquisition, it requires that on-chip analog compar-
ators be used as part of the process. These analog comparators are not controlled directly by
the CAT module, but by a separate Analog Comparator (AC) Interface. This interface must be
configured properly and enabled before the CAT module is used. This includes configuring the
generic clock input for the analog comparators to the proper sampling frequency.
When an external debugger forces the CPU into debug mode, the CAT continues normal opera-
tion. If the CAT is configured in a way that requires it to be periodically serviced by the CPU
through interrupts or similar, improper operation or data loss may result during debugging.
The CAT module can perform three types of QTouch acquisition from capacitive touch sensors:
autonomous QTouch (one sensor only), QTouch group A, and QTouch group B. The CAT mod-
ule can also perform QMatrix acquisition. Each type of acquisition has an associated set of pin
selection and configuration registers that allow a large degree of flexibility.
The following schematic diagrams show typical hardware connections for QTouch and QMatrix
sensors, respectively:
Figure 28-2. CAT Touch Connections
32-bit AVR
Chip
SNSKn
SNSn
Cs (Sense Capacitor)
AT32UC3L016/32/64
QTouch
Sensor
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