CY8C20236A CapSense System

CY8C20236A CapSense System
The analog system contains the capacitive sensing hardware.
Several hardware algorithms are supported. This hardware
performs capacitive sensing and scanning without requiring
external components. The analog system is composed of the
CapSense PSoC block and an internal 1 V or 1.2 V analog
reference, which together support capacitive sensing of up to
33 inputs
[2]
. Capacitive sensing is configurable on each GPIO
pin. Scanning of enabled CapSense pins are completed quickly
and easily across multiple ports.
SmartSense?
SmartSense is an innovative solution from Cypress that removes
manual tuning of CapSense applications. This solution is easy to
use and provides a robust noise immunity. It is the only autotuning solution that establishes, monitors, and maintains all
required tuning parameters.  SmartSense allows engineers to go
from prototyping to mass production without re-tuning for
manufacturing variations in PCB and/or overlay material
properties.
Figure 1.  CapSense System Block Diagram
Analog Multiplexer System
The Analog Mux Bus can connect to every GPIO pin. Pins are
connected to the bus individually or in any combination. The bus
also connects to the analog system for analysis with the
CapSense block comparator.
Switch control logic enables selected pins to precharge
continuously under hardware control. This enables capacitive
measurement for applications such as touch sensing. Other
multiplexer applications include:
■ Complex capacitive sensing interfaces, such as sliders and
touchpads.
■ Chip-wide mux that allows analog input from any I/O pin.
■ Crosspoint connection between any I/O pin combinations.