Sample schematics shows a device that has:
- one input pin connected to a button
- one output connected to a led.
Schematic is drawn on Eagle 7.5.0
| Name | Type | Description |
|---|---|---|
| IC1 | Microchip PIC16F1454 | Simple inexpensive microcontroller with built in support for USB. Can sync 48 MHz internal oscillator with USB clock with only internal components. |
| CN1 | USB Connector | For connecting device to host |
| S1 | Button switch | Simple push button for providing input. Is connected to PICs input that has internal weak pullup. |
| L1 | Ferrite Bead 33 Ohm @ 100MHz | For suppressing high frequency noise on USB power |
| R1 | 1 Mohm resistor | Connects USB shield with ground |
| R2 | 300 ohm resistor | Current limiting resistor for led. For 2V forward Voltage led with 10mA Current. Formula: (5V - Led Forward Voltage) / Current |
| C1 | 0.47 µF capacitor | For stabilizing PICs internal 3.3V LDO regulator |
| C2 | 0.1 µF capacitor | For VDD decoupling (required for USB with internal oscillator) |
| C3 | 1 nF capacitor | For VDD decoupling (required for USB with internal oscillator) |
| LED1 | Led | Any led. Adjust R2 according to forward voltage and desired current. Max 10mA current recommended. |
| JP1 | Pinheader | In Circuit Serial Programming header |