at42qt1011 ATMEL Corporation, at42qt1011 Datasheet - Page 6

• Manufacturer Part Number: at42qt1011
• Description: One-channel Touch Sensor Ic
• Manufacturer: ATMEL Corporation

3.2
3.3
6
Threshold
Max On-duration
AT42QT1011
Figure 3-3.
However, once SYNC mode has been entered, if the SYNC signal consists of a series of short
pulses (>10 µs) then a burst will only occur on the falling edge of each pulse
page
In SYNC mode, the device will sleep after each measurement burst (just as in LP mode) but will
be awakened by a change in the SYNC signal in either direction, resulting in a new
measurement burst. If SYNC remains unchanged for a period longer than the LP mode sleep
period (about 80 ms), the device will resume operation in either Fast or LP mode depending on
the level of the SYNC pin
There is no detect integrator (DI) in SYNC mode (each touch is a detection); see
Recalibration timeout is a fixed number of measurements so will vary with the SYNC period.
Figure 3-4.
The internal signal threshold level is fixed at 10 counts of change with respect to the internal
reference level, which in turn adjusts itself slowly in accordance with the drift compensation
mechanism.
The QT1011 employs a hysteresis dropout of two counts of the delta between the reference and
threshold levels.
The max on-duration of this device is infinite; that is, the device will not automatically recalibrate
due to a persistant detection.
6) instead of on each change of SYNC signal, as normal
SYNC
SYNC
SNSK
SNSK
SYNC Mode (Triggered by SYNC Edges)
SYNC Mode (Short Pulses)
SNSK
SYNC
(Figure
>10us
sleep
sleep
3-3).
sleep
sleep
>10us
>10us
slow mode sleep period
slow mode sleep period
sleep
sleep
(Figure
3-3).
Revert to Slow Mode
Revert to Fast Mode
(Figure 3-4 on
9542G–AT42–03/10
Section
3.4.