P-Star 25K50 Micro

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. Onboard 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.

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
• Many 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
  • 13 pins can be configured as analogue inputs
  • 2 PWM output signals (one of which can be sent to four different pins)
  • 5-bit digital-to-analogue 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

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.

Dimensions

General specifications

Notes:

1

Without included optional headers. This measurement includes the USB Micro-B connector, which extends 0.05″ past the edge of the PCB.

2

Without included optional headers.

3

8 KB of the MCU's 32 KB of flash memory is used by the pre-installed USB bootloader. All 32 KB is available if you use an external programmer and erase the bootloader.

4

All 16 can be used as digital I/O, 13 can be used as analogue inputs, and one can be an analogue output. An extra 2 I/O lines are accessible from the ICSP header, and RA0 is accessible on the RA0-VB jumper.

5

On VIN.