Cypress Semiconductor CY3280-MBR3 ユーザーズマニュアル

CY3280-MBR3 Evaluation Kit User Guide, Doc. #: 001-89905 Rev. *B

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Kit Operation

The CY3280-MBR3 EVK includes the following features:

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Four CapSense buttons of two different sizes – two buttons of 10-mm diameter (BTN1 and 
BTN2) and two buttons of 11-mm diameter (BTN3 and BTN4)

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LEDs corresponding to sensors indicating button touch

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A buzzer

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Shield electrode pin for water tolerance

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I

2

C selection jumpers

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Arduino-compatible headers

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One proximity loop and a corresponding LED to indicate proximity state (on/off)

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A host interrupt pin

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Two slide switches on two CapSense buttons to vary trace capacitance and demonstrate 
SmartSense Auto-Tuning

Note: The CS15 pin of the MBR3 device is multiplexed for the CapSense button, host interrupt, and
shield electrode. Similarly, GPO7 is multiplexed for general-purpose output, host interrupt, and
buzzer output. All three features – host interrupt, buzzer, and shield electrode (water tolerance) can-
not be enabled simultaneously. See 

 for more details on CS15 and GPO7 pin connections.

3.4.1

SmartSense Auto-Tuning Feature

The CY8CMBR3116 device features SmartSense Auto-Tuning, which is the Cypress proprietary
CapSense algorithm that compensates for system, manufacturing, and environmental changes while
providing feature-rich CapSense solutions.

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Reduces design effort by eliminating tedious manual tuning

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Adapts to variations in PCB, overlay, paint, and manufacturing that degrade touch-sensing per-
formance

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Eliminates production-related manual tuning

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Adapts to changes in system environment due to noise sources

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Allows a platform design approach with different overlays, button shapes, and trace lengths

The CY8CMBR3116 also supports setting manual thresholds to override the auto-tuning mecha-
nism, if required.

SmartSense Auto-Tuning is demonstrated using three methods on the kit. See 

 for hardware details:

1. Using the SW1 slide switch to increase capacitance

a. Power on the kit using USB or an external power supply on pin 4 of the J1 header.

b. Touch BTN2 on the kit; the corresponding LED will turn on, providing visual feedback on each 

button touch.

c. Increase the capacitance of BTN2 by sliding SW1 to add an additional 10-pF or 15-pF exter-

nal capacitance on the sensor, as shown in 

; the LED turns on as if a touch 

occurred due to the increase in capacitance. Now, press the reset switch, SW2, to reset the 
board.

d. Touch BTN2 on the kit; the corresponding LED works normally. This demonstrates the 

SmartSense Auto-Tuning algorithm, which automatically tunes for the increased CapSense 
button capacitance.