1. Crystal Free USB with mTouch Demonstration

2. Kit Contents 3ft USB A to mini-B 5pin 28/28AWG Cable
USB Keypad w/ bumpers
USB Keypad Block Diagram
3ft USB A to mini-B 5pin 28/28AWG Cable
Lumvatech Company Profile Insert

3. Crystal Free USB Keypad with mTouch
Demonstration Highlights
All features driven by single device – PIC16F1459
Crystal free USB operation
18 touch buttons using Capacitive Voltage Divider (CVD) technique
LED backlight with proximity sensing ON and auto power OFF
USB HID interface
Plug and play
Low cost lightweight design
Audio feedback using the piezo buzzer
Development Made Easy
Low-cost development experience
Start with the FREE download
Schematics & ‘C’ source code
Easily modified to your specific application needs
Download at

4. Crystal Free USB Keypad – Block Diagram
PIC16F1459 device with USB, 9 Channel ADC, PWM, Active Clock Tuning, etc.
USB powered device
Current consumption < 100 mA

5. Matrix Key Design Uses mTouch CVD technique
COLOUMN 0
COLOUMN 2
Key size 12mm*12mm
Uses mTouch CVD technique
9 ADC channels - 5 rows * 4 columns
Two columns are also used as proximity sensors
Guard ring to reduce parasitic capacitance on sensors
CVD application note • •
COLOUMN 1
COLOUMN 3 • • • • •
ROW 0 S1 S2 S3 S4 • • •
ROW 1 S5 S6 S7 S8 •
ROW 2 S9
S10
S11
S12 • •
ROW 3 • •
S13
S14
S15
Guard • •
ROW 4
S16
S17
S18
Key size 12mm*31mm
Guard ring 3mm away from sensors. Thickness 1mm. 5 5

6. Lumvatech Graphics, Panel, Keypad PCB
Top panel with graphics printed on it.
12 side firing LEDs (6 on each side) provide backlighting.
Panels are provided by Lumvatech. (

7. High level Firmware Architecture
Application
(keyboard.c)
HID Function Driver
(usb_function_hid.c)
USB Device Stack
mTouch CVD Stack
LED and Buzzer
Firmware Integrates
USB Device Stack
mTouch CVD stack
Both the stacks are part of MLA
MLA is freely downloadable at

8. Simplified Application Flow Chart
main()
Initialize USB, mTouch() A
ISR
Send 0x00 to Host
Is any valid mTouch key press detected?
Is USB Device in Configured state? No No
USBDeviceTasks();
Yes
Yes
Is Last USB transfer completed?
mTouch_Scan(); No
Is proximity Sensor press detected? No
LEDService();
Yes
Yes
Send corresponding key to Host
Activate Keypad
Turn ON LED backlight
End of ISR
Buzzer Beep A

9. Audio Feedback When Num Lock is ON, buzzer beep frequency is 1000hz
When Num Lock is OFF, buzzer beep frequency is 2500hz
Slightly longer beep for Num Lock ON and OFF
Hold the Clear key for 2 Sec to turn ON/OFF the buzzer feedback. Hold the key until a longer beep is heard from the buzzer.

10. USB Keypad Summary All features driven by single device – PIC16F1459
Active Clock Tuning for crystal Free USB
Saves as much as $0.15 by eliminating external crystal
Guarantees 0.25% accuracy when connected to USB host
USB HID interface – plug and play
Capacitive touch sensing based on CVD technology
LED backlight with proximity sensing ON and auto power OFF
Sleek and low cost design
Easily modified to specific application needs
Download schematics & code at:

11. Learn more…
Visit us on the web:
Quick start guide
Application note and ‘C’ source code
Schematic and board files
Visit us on the web:
USB Development Platforms
USB Reference Designs
USB Application Notes
USB Products & Peripherals

12. Partner Overview
A leading provider of microcontroller and analog semiconductors, providing low-risk product development, lower total system cost and faster time to market. With an increasing focus on lighting applications, Microchip offers outstanding technical support along with dependable delivery and quality.
A leading U.S. based manufacturer of ultra-thin backlighting that provides solutions from simple logo backlighting to complete user-interfaces. Lumvatech serves the medical, white goods, brown goods, and automotive industries with easy integration, fast speed to market, and high-quality lit products.