sx8661 Semtech Corporation, sx8661 Datasheet - Page 55

• Manufacturer Part Number: sx8661
• Description: Low Power, Capacitive Button Touch And Proximity Controller 8 Sensors With Led Drivers And Analog Output
• Manufacturer: Semtech Corporation

ADVANCED COMMUNICATIONS & SENSING
As soon as the ticks become larger than the CAP thresholds (see registers of the previous section) plus the
hysteresis (defined in register
In the example of Figure 53 the touch is validated after 2 ticks (
The release is detected immediately (
hysteresis.
BtnCfg
Revision v3.2, January 2011
The SX8661 button and proximity interface has three modes of operation:
Table 21 resumes the relation of reporting modes and information on the interfaces.
The user can select to have the interrupt signal (INTB) on touching a button (proximity detected), releasing a
button (out of proximity) or both.
In noisy environments it may be required to debounce the touch and release detection decision.
•
•
•
Reporting
Strongest
Report All: reports all touches of multiple fingers and proximity detection.
Report Single: reports only a single touch and/or proximity. Subsequent touches are ignored until the
first touch is released. On the AOI proximity is implicit in case of a button touch.
Report Strongest: reports the strongest touch. When the signal from another sensor rises above the
first sensor’s signal, the second sensor is then reported instead. On the AOI proximity is implicit in
case of a button touch.
Single
Mode
All
1 Button and Proximity
1 Button and Proximity
Buttons and Proximity
BtnHysteresis
Proximity or
Proximity or
I2C
Figure 53
Low Power, Capacitive Button Touch and Proximity Controller
BtnCfg
Table 21
) the debounce counter starts.
© 2011 Semtech Corp.
Touch and Release Example
[3] = 0) at the first tick which is below the threshold minus the
Idle or 1 Button or
Idle or 1 Button or
Reporting modes
Forced to Idle
55
(8 sensors) with LED Drivers and Analog Output
Proximity
Proximity
AOI
BtnCfg
[2:0] = 1).
GPIOs (LEDs)
Buttons and
Buttons and
Buttons and
Proximity
Proximity
Proximity
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DATASHEET
Buzzer
Button
Button
Button
SX8661