at42qt2100 ATMEL Corporation, at42qt2100 Datasheet - Page 19

• Manufacturer Part Number: at42qt2100
• Description: Qtouch Touch Sensor Ic
• Manufacturer: ATMEL Corporation

4.4.5
9554CX–AT42–11/11
Sync Mode
This mode can be used by the host to create its own “LP Mode” timings via the SS wakeup
pulse method.
This mode is useful for low frequency noise suppression, for example from mains frequencies
in line-operated appliances. Acquisition bursts are synchronized to the SS-wake pulses from
the host.
Sync mode is very similar to LP Mode 4, with two differences:
Not operating as in Free Run mode when a touch is first detected (before DI confirmation has
taken place) means that acquisition bursts are restricted to the immediate time after a sync
signal (SS), heightening the effect of low frequency noise suppression.
In many applications of Sync mode the DI filter will need to be set to two counts, to avoid the
QT2100 response time being unacceptably lengthened as a consequence of this.
• It does not operate as in Free Run mode when a touch is first detected
• The LPB bit is ignored and a burst is always generated after each SS wakeup or SPI
transfer as if LPB = 1
AT42QT2100
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