My PIC18F2X5X Dev Board

My version of the nuxie1 Hackaday Competition Entry (a PIC18F2550 development board).

The nuxie1 Hackaday Competition Entry is a microcontroller development board. It uses the PIC18F2550 microcontroller and a modified version of the Microchip USB bootloader. It allows a fast development cycle by allowing programming of the PIC through the USB interface built into the PIC itself (after you’ve put the bootloader into it the first time using ICSP). It has a certain amount in common in that respect with the Arduino.

After seeing nuxie1’s comments on hackaday, I was inspired to try porting his board to Kicad from Eagle and experience all the fun/challenge of routing the board manually on a single sided board using no jumpers or vias. I should probably mention at this point that his board is much better looking than mine and comes in more through-hole/smd/hybrid versions.

My version of this development board has a few extra pin headers for ease of plugging things in and a relay for driving bigger loads.

Here’s the schematic for my version [ps], [svg], [jpg]. And here’s the whole KICAD project source if you fancy rolling your own.

A few notes on the design criteria for this project:

  • Board should be single sided for easy home manufacture
  • Board should be approx credit card sized (like the original)
  • Board should use (larger and easy to solder) surface mount components to avoid having to drill lots of holes
  • Board should be configurable with jumpers to run at 3.3V or USB power (5V)
  • 5×2 pin headers should be used for all ports
    • to reduce the number of types of part to source
    • to allow connection to other boards using simple IDC connectors and ribbon cable
    • because the surface mount versions stand up nicely for soldering,
  • Ports available:
    • PortA – use as a 6 pin port. Note that pin A0 is connected to the relay.
    • PortB – use as an 8 pin port. Note that pins B0 and B1 are also used by the Synchronous Serial Port (e.g. for I2C or SPI)
    • PortC – has no header for the complete port.
      • pin C0 is used for the switch which puts the board into bootload mode.
      • pin C1 and C2 come out on the PWM header for use as PWM outputs
      • pins C4 and C5 are the USB port
      • pins C6 and C7 are used by the Asynchronous serial port (e.g. for RS232)

With all of that in mind, here is the PCB artwork. It is mirror image (which is what you want for toner transfer or transparencies anyway). [ps], [pdf]. If you want the KICAD source, it’s in this ZIP file.

Here’s one I made earlier. It’s a bit of a mess – covered in flux and solder. My excuse is that I was having some soldering iron trouble when I made this one. But it does work 🙂

To use the board, you will need to put this bootloader on it using a PIC ICSP programmer.

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