TAP-28 - A “throw away” PIC board


TAP-28 Introduction

Microprocessor applications often require only a simple microprocessor circuit to control an external board, read a few sensors, control a motor or LED using PWM or even run a servo. Implementation of such a circuit is a hassle: dedicating a complex dev board to the task, maybe using a solderless breadboard or hand-assembling the circuit on perf board. None of these is an ideal solution, costing more than needed, having a less-than-robust solution or taking more time than should be needed.

An extremely low-cost circuit that can accomplish simple tasks without any extra hardware or features, yet can serve as a building block to more complex projects would be an ideal solution. The “Throw-Away PIC” (TAP-28) circuit board is so cheap that it can be dedicated to a project without worrying about getting it back.


The TAP-28 supports many of the popular PIC 18F-series 28 pin parts. It includes 2 general-purpose pushbutton switches and 4 LEDs, connectors for ICSP, UART and I2C/SPI and includes 2 analog input/general purpose and 2 PWM/general purpose I/O connectors on a 2" x 3.25" 2-sided printed circuit board. The board uses through-hole parts for easy assembly. A daughter board may be connected to use additional components with this board.

The TAP-28 is designed to support growth in the PIC development community, and as such, the design is licensed to the community under a Creative Commons License detailed elsewhere in this document.

No claims are made as to the performance or reliability of this board, nor to its suitability for any particular application. No safeguards to protect an inexperienced user from causing damage to the microcontroller have been included on this board – this board is intended as an alternative to a hand-assembled perf board, so some level of knowledge is assumed.

To determine if a particular PIC microprocessor is suitable for use on this board, compare its pinouts to the examples shown. For technical support, please consult your favorite PIC forum.


TAP-28 "Throw Away PIC" Printed Circuit Board by Jon Chandler is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.

Permissions beyond the scope of this license may be available from the creator.Waiver is hereby granted for commecial use of the TAP-28 "Throw Away PIC"Printed Circuit Board as a component of systems for commercial use. ShareAlike applies specifically to modifications of the TAP-28 Printed Circuit Board,not to systems using the TAP-28 Printed Circuit Board.

Attribution of the use of the TAP-28 "Throw Away PIC" Printed circuit board may be made by posting a description of the application to the Digital-DIY forum (www.digital-diy.com) and via email to Jon Chandler (This email address is being protected from spambots. You need JavaScript enabled to view it.)

1. Ground plane is discontinuous on bottom side of board. See illustration on following page.Workaround: jumper across break.

  • Workaround priority: Mandatory
  • Fix: Revise Gerber files

2. Positive power plane is discontinuous on bottom side of board, leaving an unconnected area on the top left side of the board. See illustration on following page.Workaround: jumper unconnected area.

  • Workaround priority: Mandatory
  • Fix: Revise Gerber files

3. Ground terminal of J10 terminal block connection is not connected.Workaround: If the J10 terminal block position is used with either a terminal block or wire leads for a power connection, jumper to J11 shell terminal for ground connection.

  • Workaround priority: Mandatory if J10 position is used
  • Fix: Revise Gerber files for future board runs.

4. Upper right mounting hole is out of position (near USB connector).

  • Workaround: be aware of non-symmetric mounting holes.
  • Fix: Revise Gerber files for future board runs.


The image above displays where and what to do.



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