PIC24 and PIC32 SOIC28 Breakout Board design overview
From DP
Intro and goal
features
- Features (list)
- Features
You can get a [project for $20], including worldwide shipping.
Read about the design below.
Contents |
Overview
History and related links
Hardware
Click for a full size schematic image. Schematic and PCB were designed with the freeware version of Cadsoft Eagle, download the latest project files from our Google Code project page.
Microcontroller section
The board was designed for PIC24 and PIC32 microcontrollers )IC1)that come in SOIC-28 packages. They are powered either through the external DC barrel jack or directly from the USB which is filtered with a ferrite bead (L1). The source of power is selected through the PWR jumper.
A 3.3v voltage regulator (VR) is decoupled on its input via a 0.1uF capacitor(C6), and on it's output with a 10uF capacitor (C7). All the power pins of the microcontroller have been bypassed with 0.1uF capacitors (C3 and C4). The MCU's internal voltage regulator pin (VCAP) is bypassed with a 10uF capacitor.
An external clock is provided by a XXMHz quartz crystal (X1) and two load capacitors (C1 and C2).
The ICSP programing connection is brought to a header for easy development. The MCLR (RESET) programming pin is connected to the power supply through a 10K pull-up resistor (R2).
Also available are two LEDs. One (PWR) is connected to the power supply, and the other to the pin 14 of the MCU. They are both current limited with 1K resistors (R3 and R4)
USB
Broken out Pins
PCB
We used the freeware version of Cadsoft Eagle to make the schematic and PCB. Download the latest designs and firmware from the project Google Code page.
- PCB and placement notes
- soldering advise
Partslist
Click for a full size placement image.
| heading | heading |
|---|---|
| cell | cell |
| cell | cell |
Firmware
The firmware is written in C and compiled with the free Microchip C18 compiler. You can download the latest files from our Google Code project page.
- Operating modes
- extra software required
We used the Microchip USB stack to run the 18F2550 as a virtual serial port. Microchip's code is open but not redistributable. If you want to compile the source, download the stack from Microchip, then drag the source code into the install directory. See the detailed instructions in the PIC compiler how-to.
.inf installation
The virtual serial port (CDC) is an open standard, it should work on any modern operating system.
You don't need a driver, but you will need a .inf file to tell Windows how to use the device. A suitable .inf is included in the project archive.
Commands
Bootloader
Source and license
Taking it further
Here's some ideas for the future:
- List
We'll post the most recent firmware updates on our blog. You can also join the discussion in the [forum].
Get one!
You can [get one for $00], including worldwide shipping.
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