Capacitance Sensing - Calibrating CapSense with
the CSR User Module
February 22, 2006
Document No. 001-25459 Rev. **
Author: Darrin Vallis
Associated Project: Yes
Associated Part Family: CY8C21x24, CY8C24x94
GET FREE SAMPLES HERE
Software Version: PSoC® Designer™ 4.2 SP3
Associated Application Notes: AN2233a, AN2277, AN2292, AN2318
Application Notes Abstract
This Application Note describes the steps necessary to select, place and calibrate the CSR (Capacitive Switch Relaxation
Oscillator) User Module for CapSense applications.
Cypress’ PSoC is an extremely versatile system-on-chip
device. Its capabilities allow engineers to solve problems
and develop exciting new products. One of the most
unique features available in PSoC is capacitive sensing.
PSoC is able to detect the presence of a finger through
glass, plastic, acrylic or many other non-metallic materials,
using a simple PCB trace as the sensor.
See Application Note AN2233a Capacitive Switch
Scan”for more on the actual physics and electrical
engineering of PSoC capacitive sensing.
Designers are free to implement buttons, sliders or any
type of touch-based user interface. This is a significant
advantage for consumer electronics. Many of the most
popular devices on the market today have a PSoC
capacitive sense interface.
This Application Note helps an engineer implement their
first capacitive sense design. Even though PSoC Designer
has a user module that provides all necessary hardware
connections, software APIs, and does a
sophisticated background processing, it still has to be
Designers must be at least familiar with PSoC architecture
and the PSoC Designer development environment.
Cypress Field Applications Engineers are available for just
such information. Go to http://www.cypress.com/, click on
“About Cypress” in the sidebar and then “Cypress
Locations.” Local Sales Offices can put designers in touch
with FAEs for questions or ev