The P-Star 25K50 Micro is a tiny programmable module featuring Microchip’s PIC18F25K50 microcontroller. It packs a Micro-USB interface and 19 digital input/output pins onto a board measuring only 1″ × 0.6″ and ships preloaded with a USB bootloader, so no external programmer is required.

P-Star 25K50 with U.S. quarter for size reference.

Overview

The Pololu P-Star 25K50 Micro is a general-purpose programmable module based on Microchip’s PIC18F25K50 microcontroller, which has 32 KB of flash program memory, 2 KB of RAM, and built-in USB functionality. On-board features of the P-Star (abbreviated P*) include a 16 MHz crystal, a USB Micro-B connector, and three user-controllable indicator LEDs. A voltage regulator and power selection circuit allow the board to be powered from either USB or an external 5.5 V to 15 V source, while a resettable PTC fuse on the USB VBUS supply and reverse protection on VIN help protect it from accidental damage. The board ships with a USB bootloader that makes it easy to program the PIC microcontroller without using an external programmer.

Our comprehensive user’s guide provides the basics you need to get started with the P-Star 25K50 Micro as well as detailed technical information.

This product requires a USB A to Micro-B cable (not included) to connect to a computer.

P-Star 25K50 Micro, bottom view.

P-Star 25K50 Micro, top view.

Features

Dimensions: 1″ × 0.6″ (1.05″ × 0.6″ including USB Micro-B connector)

Programmable Microchip PIC18F25K50 microcontroller 32 KB flash (8 KB used by bootloader, leaving 24 KB available for user program by default) 2 KB SRAM 256 bytes of EEPROM Native full-speed USB (12 Mbps)

5 V logic voltage

Internally clocked at 48 MHz, resulting in execution speeds up to 12 million instructions per second (MIPS)

Precision 16 MHz crystal

19 I/O lines in a small package 16 user I/O lines along the sides of the board 3 additional I/O pins available in other locations 14 pins can be configured as analog inputs 2 PWM output signals (one of which can be sent to four different pins) 5-bit digital-to-analog converter (DAC) output

Three user-controllable LEDs

USB Micro-B connector

Can be powered from USB or external source regulated to 5 V by onboard regulator

Operating voltage: 5.5 V to 15 V Can operate down to 3.8 V with decreased logic voltage

Reverse-voltage protection on external power input

PTC fuse on VBUS supply

Ships with a proprietary USB bootloader developed by Pololu for the P-Star

Bootloader is usable from Windows, Linux, and Mac OS X with open source software

No external programmer required

Compatible with standard Microchip compilers, development tools, and programmers

Comprehensive user’s guide

Pinout

P-Star 25K50 Micro pinout diagram.

This diagram identifies the I/O and power pins on the P-Star 25K50 Micro. The diagram is also available as a printable PDF (161k pdf). For more information about the PIC18F25K50 microcontroller and its peripherals, see Microchip’s PIC18F25K50 documentation.

Included hardware

Two 1×10-pin breakaway 0.1″ male headers and one 1×6-pin breakaway 0.1″ male header are included with the P-Star 25K50 Micro. These header pins can be soldered in to use the board with perfboards, breadboards, or 0.1″ female connectors.

P-Star 25K50 Micro with included optional headers. The P-Star 25K50 Micro with soldered headers and connected USB cable.

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