Crystal Free USB with mTouch Demonstration www.microchip.com/USBkeypad www.microchip.com/usb Kit Contents • USB Keypad w/ bumpers • USB Keypad Block Diagram • 3ft USB A to mini-B 5pin 28/28AWG Cable • Lumvatech Company Profile Insert 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 www.microchip.com/USBkeypad 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 Matrix Key Design COLOUMN 2 COLOUMN 0 COLOUMN 3 COLOUMN 1 • Key size 12mm*12mm • • ROW 0 • • • S2 • S1 S3 • S4 • • ROW 1 • • • S6 • S5 S7 • S8 • • ROW 2 • • • S10 • S9 S11 • S12 • ROW 3 • S13 • S14 S15 Guard • ROW 4 S16 • S17 Guard ring 3mm away from sensors. Thickness 1mm. S18 Key size 12mm*31mm 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 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. (www.lumvatech.com) High level Firmware Architecture Application (keyboard.c) (usb_function_hid.c) mTouch CVD Stack LED and Buzzer Firmware Integrates HID Function Driver USB Device Stack USB Device Stack mTouch CVD stack Both the stacks are part of MLA MLA is freely downloadable at www.microchip.com/MLA Simplified Application Flow Chart main() Initialize USB, mTouch() A ISR Send 0x00 to Host No No Is USB Device in Configured state? Is any valid mTouch key press detected? USBDeviceTasks(); Yes Yes mTouch_Scan(); No No Is proximity Sensor press detected? Is Last USB transfer completed? LEDService(); Yes Yes •Activate Keypad •Turn ON LED backlight Send corresponding key to Host End of ISR A Buzzer Beep 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. 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: www.microchip.com/USBkeypad Learn more… Visit us on the web: www.microchip.com/USBkeypad Quick start guide Application note and ‘C’ source code Schematic and board files Visit us on the web: www.microchip.com/USB USB Development Platforms USB Reference Designs USB Application Notes USB Products & Peripherals Partner Overview A leading provider of microcontroller and analog semiconductors, providing lowrisk 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.