Cypress CapSense CY8C20x36 Guide de l'utilisateur télécharger pdf (Page 32)

32 Document No. 001-64846 Rev. *I Getting Started with CapSense

Figure 2-33. Two-Layer Stack-up of a CapSense Board

Four-layer designs are an option when board area must be minimized. PCB layout plays a very important role in

CapSense system performance. Best practices are discussed in Design Considerations.

2.9.2 Firmware Component

Firmware is a vital component of the CapSense system that processes the raw count data and makes logical

decisions. The amount of firmware development required for your application depends on which CapSense controller

family that you select.

Devices from the CapSense Express family are fully configurable either through hardware or through I

C and do not

require any firmware development on the CapSense controller itself. These devices are appropriate for systems

where the finger touch data is sent to a host for higher level processing; see Figure 2-34.

Figure 2-34. Example CapSense Express System Implementation

Capacitance

Measurement

(Hardware)

Decision

Logic

(Firmware)

CapSense Controller

Decision

Logic

(Firmware)

Non-CapSense

Actions

Application

Functions

Host

Sensors

Devices from the CapSense and CapSense Plus families are fully programmable. These devices allow complex

system level integration. These controllers can process the raw count data as well as perform other system functions.

See the CapSense Product Portfolio and CapSense Selector Guide for additional details. Cypress‘s PSoC Designer

accommodates firmware development in C and assembly language. See Resources for more information on this and

other tools.

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Cypress CapSense CY8C20x36 Guide de l'utilisateur Page 32