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Crystal Free USB with mTouch Demonstration

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Presentation on theme: "Crystal Free USB with mTouch Demonstration"— Presentation transcript:

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.

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