What are the differences between the original TAP-28 and the TAP-28 Rev A board?
The revision was done mainly to fix a couple gaps in the ground and power planes that crept in at the last minute in the original TAP-28 design. But this made a great opportunity to make some improvements based on experiences with the TAP-28.
What's the purpose of the TAP-28 board?
The TAP-28 board was designed to be used in embedded applications as an alternative to expensive development boards or hand-built perf boards that are time consuming to make. The goal was an inexpensive board that could be dedicated to a project without much worry about cost.Which controllers can be used on the TAP-28 board?
The TAP-28 also features connectors for commonly used external devices for reliable long-term connections in embedded applications.
The TAP-28 doesn't include features frequently found on development boards but usually not needed for embedded applications.
28-pin narrow DIP devices fit on the board. A list of devices known to fit is available here. For parts not on the list, compare the pinouts to those shown on that page - any device with the same pinout may be used. If VDD and ground are in the same location but other pins are in different locations, the device may be used, but the mapping to the on-board LEDs and switches and connectors may be different.
What compilers can be used with the TAP-28?
The TAP-28 isn't tied to any particular compiler or language. Anything that generates PIC-compatible code will work. A few options are shown here, some of which are free.
What programmers can be used with the TAP-28?
The TAP-28 has a standard 6 pin connector for ICSP (In Circuit Serial Programming) which is supported by many programmers. Recommended Programmers
Why isn't the TAP-28 sold as an assembled board?
A variety of components may be used on the TAP-28 board including different controllers and LEDs depending on the application and user preferences. Additionally, some parts will not be needed in some applications, so providing a bare board allows for customization.
How difficult is assembling a TAP-28 board?
The TAP-28 uses through-hole parts for easy assembly. While it's not designed as a beginner's kit, if you can follow a schematic diagram, you'll have no problems. The User's Guide covers assembly and lists the function of each component to help with parts selection.
A low-wattage soldering iron, rosin-core solder and small diagonal cutters are needed for assembly.
Where can I get parts for a TAP-28?
A basic parts list in shown here and there are links to a parts list with manufacturers information and Digikey part numbers. Most of the parts are non-critical and may often be found in a hobbyist's junk box. All of the parts are available at Digikey although other sources will be cheaper.
Check the products page. A limited number of parts kits are available. Bulk buys and alternative sources keep the cost of these kits low.
How can I power the TAP-28 if I don't want to use a USB connection?
The TAP-28 doesn't have a voltage regulator on-board. For systems operating from line power, a 5v regulated "wall wart" power supply from a cell phone is often a great choice. The PIC 18F K-series and L-series parts operate from low voltage - 2 AA batteries are an ideal power supply.What precautions should be taken with the TAP-28 board?
The TAP-28 is designed as an alternative to using a hand-built perf board circuit. As such, some user knowledge is assumed and the TAP-28 doesn't feature common protection features designed into development boards. Reverse polarity power connection fry the microcontroller. Shorting an output to V+ or ground, or tying two outputs together will damage the microcontroller. The user is responsible for their own stupidity.I want to use the TAP-28 in a commercial product. Is this ok?
Absolutely! The TAP-28 is licensed under a Creative Commons 3.0 Share Alike license. The license excludes commercial use but grants an exception for selling the TAP-28 as a component of a larger system. For large-volume users, Gerber files will be provided at no cost so boards can be made by the vendor of your choice.Why are there "extra" port pins on the UART Connector? Only RxD and TxD are needed but INT0 and INT1 are also present on this connector.
The TAP-28 board itself (not as a component of a larger system) may not be sold commercially without the express permission of its creator.
When the UART connector is used for serial communication, RxD and TxD are used. But all of the 6-pin connectors on the TAP-28 can be used for general-purpose I/O; so if the UART isn't used, this connector has 4 general-purpose port pins that can be used as desired. In the Irradiance Meter project for example, the I2C/SPI connector was used to interface to the light sensor. Two of the available port pins were used to control the sensitivity and a third pin was used to read the pulse stream output of the sensor.
TAP-28 Used For Geeky Clock. A 5V Regulated Power Supply
Was Later Connected At The Terminal Block Pads