Cypress Semiconductor CY3280-MBR3 データシート

Document Number: 001-85330 Rev. *G 

Page 3 of 37

A capacitive sensor detects changes in capacitance to determine 

the presence of a touch or proximity to conductive objects. The 

capacitive sensor can be a capacitive button that replaces the 

traditional mechanical buttons, a capacitive slider that replaces 

mechanical knobs, or a proximity sensor that replaces an 

infrared sensor in a user interface solution. A typical capacitive 

user interface system consists of the following:

■

A capacitive sensor

■

An audio-visual output, such as a buzzer or an LED

■

A capacitive sensing controller connected to the sensor

■

A host processor

The capacitive controller connects the sensor and the output to 

the host processor through a communication interface, such as 

an I

2

C or a GPO. 

The capacitive user interface system serves as a 

human-machine interface that takes the user’s touch inputs and 

provides audio-visual feedback through a buzzer or an LED. 

CY8CMBR3xxx is a family of capacitive sensing controllers, 

which senses the change in capacitance based on touch or 

proximity, and controls the user interface system accordingly. 

The sensing algorithm, built in the controllers, determines the 

presence of touch and drives the outputs or sends signals to the 

host processor. This algorithm can distinguish between the 

signal (based on touch or proximity) and noise, which can be 

caused by environmental or electrical conditions. 

 shows a typical user interface system with capacitive 

buttons connected to a CY8CMBR3xxx CapSense Express 

controller, which controls the system and also communicates 

with the host processor through I

2

C.

Traditionally, capacitive sensing controllers require firmware 

development to perform specific user interface functions and 

manual system tuning to achieve optimal performance. 

However, the CY8CMBR3xxx CapSense Express family of 

controllers does not require any firmware development, acceler-

ating time-to-market. These devices feature SmartSense 

Auto-tuning, which eliminates the need for manual tuning, 

providing optimal performance even under extremely noisy 

conditions.

CY8CMBR3xxx 

CapSense Controller

Buzzer

LEDs

Host

Processor

I2C

HI 

Linear Slider

Radial Slider

CapSense Sensors

CapSense Buttons

Outputs

Host Interrupt