Datasheet

4
Microchip Human Interface Solutions
mTouch Sensing Solutions
www.microchip.com/mtouch
*Code also supports dsPIC33 DSC.
Metal Over Cap Technology
mTouch capacitive touch solutions allow users to work with a
variety of plastic or glass overlays to finish their user interface
designs. With metal over cap technology users can also:
■ Use polished or brushed metal surfaces including
stainless steel and aluminium
■ Sense through gloves
■ Create water-proof designs
■ Deploy Braille-friendly interfaces
How Metal Over Cap Technology Works
The front panel and the sensor create
a capacitor. When the user presses the
key, the distance between both plates will
decrease slightly, increasing the capacitor
value. Thanks to their high SNR (Signal to
Noise Ratio) and stability over voltage and
temperature, mTouch sensing solutions allow the detection of
deflection as low as 10μm.
Metal Over Cap Technology can be implemented with the
same hardware, PCB and electronics, and SW as capacitive
touch technology.
Development Tools for Capacitive Touch
Enhanced mTouch Capacitive Evaluation Kit
(DM183026-2)
The Enhanced mTouch Capacitive
Evaluation Kit provides a simple platform
for developing a variety of capacitive
touch sense applications using 8, 16
and 32-bit PIC microcontrollers. The kit
contains:
■ 8-key sensor board direct interface
■ 12-key matrix sensor board
■ 4-channel slider sensor board
■ 2-channel slider sensor board
■ Four PIC MCU processor boards:
• PIC16F1937, PIC18F46J50, PIC24FJ64GB106 and
PIC32MX795F512H
■ Diagnostic GUI to analyze touch sensor data
real-time via USB
■ PICkit™ Serial Analyzer
Additional available processor boards:
■ PIC24H mTouch Capacitive Touch Evaluation Board*
(AC243026)
■ PIC32 CTMU Evaluation Board (AC323027)
Metal Over Cap Accessory Kit (AC183026)
■ The AC182036 kit contains two
daughter boards showcasing
Metal Over Cap technology.
One board has a stainless
steel cover while the other one has a plastic one.
■ It provides an easy way to evaluate Microchip’s unique
technology, when used in conjunction with the mTouch
Capacitive Touch Evaluation Kit (DM183026-2).
mTouch Software Package
Microchip provides a fully developed and tested SW
package. It features:
■ Source code available
■ Keys, slider and wheel support
■ Matrix
■ Proximity detection with specifi c algorithm offering great
range and low power
■ Available for 8,16 and 32-bits
■ Low Power
• Capacitive sensing in less than 5μA
• Proximity sensing down to less than 1μA
■ Gesture
■ Several output mode like direct or toggle mode as well
as serial communication
■ Easy to integrate with Microchip libraries such as
Graphics or USB
■ Two way communication with PC or Master
■ Works with PCB or ITO sensors
Specific noise features include:
■ High Signal to Noise Ratio (SNR)
■ Differential touch sensing mode
■ Adjacent button rejection or “most-pressed” options
■ Active Guard Ring support
■ Self and mutual measurement
■ Automatic environmental compensation
■ Various proprietary noise fi ltering algorithms
Application Notes for mTouch
■ Techniques for Robust Capacitive Touch Sensing, AN1334
■ mTouch Metal Over Cap Technology, AN1325
■ mTouch Conducted Noise Immunity Techniques for
CTMU Peripheral, AN1317
■ Capacitive Touch Using Only an ADC (CVD)
(suitable for PIC10/12/16/24H/32 MCUs), AN1298
■ Microchip CTMU for Capacitive Touch Applications
(suitable for PIC18 and PIC24F MCUs), AN1250
■ Capacitive Touch Algorithm Simulation, AN1254