USB Small Peripheral Board (aka PIC18F14K50 Board)
Recently I’ve working with the little but smart PIC18F14K50 (or your low voltage version, PIC18LF14K50). These chips are cheap (about $2,5 at Mouser) and have low pin count, but very impressive specs:
- USB V2.0 (low and high speed);
- NanoWatt feature (sleep with 24nA!);
- 10-bit A/D converters with auto-acquisition;
- Several Internal Clock modes;
- 16KB Program Flash Memory;
- 768B SRAM;
They help me with USB development. The low pin count don’t became a problem because most of times, my projects don’t use all them (in case os PIC18F4550 or PIC18F2550).
I think that it’s a good choice to design some little USB devices, like:
- A USB accelerometer;
- A USB thermometer;
- A USB logger;
- A USB GPS;
The possibilities are awesome!
Microchip develops a kit, called “Low Pin Count USB Development Kit” to present this chip. But the Microchip kit have dimensions, don’t very suitable to work like a real USB peripheral.
So I design a little board, with minimum parts to make it work. The board is a first prototype, a experiment. If works, I’ll improve it with more polish design and features, and design one with PIC18LF14K50 for 3.3v native support and etc.
You can see the circuit and board below: