Useful Bits & Pieces

This section contains hardware that may add to TAP-28 functionality and other hardware of exceptional value.

UART - USB Adapters

UART-USB adapters can be handy during program development or for applications with a PC interface.

USB 2.0 to TTL UART 6PIN CP2102 Module Serial Converter

This is a great module available from ebay from a number of vendors for around $6.  It will supply 5V or 3.3V to the TAP-28, making it ideal for use with the 18F25K20 and Amicus compiler or other 3.3 volt parts.  It connects directly to a USB port on a PC or hub.

To find this module, search on ebay with the title above.

PL2303 USB/TTL Serial Port Converter Module

Another UART-USB alternative is this cable-type adapter, also available from a number of vendors on ebay.  This are also around $6, but are usually sold in a 2 pack.  Only 5 volts is available with this cable, but it's nice for a more professional look.

Search ebay for "PL2303 USB/TTL".  Note that the title in many ebay descriptions includes the term RS-232 but this cable is TTL level, not RS-232.

UART - RS-232 Converter

A serial connection to a PC serial port requires converting TTL levels to RS-232 levels.  A converter will also be required if the TAP-28 is going to communicate with a board using RS-232 levels

Sparkfun RS232 Shifter SMD

Sparkfun PT-00449 is a nice unit and scarely bigger than a DB-9 connector.  This converter will not supply power to the TAP-28, but its output level is the same as the supply voltage from the TAP-28 so it may be used with 5V or 3.3V parts.

Prototyping Boards and Hardware

A variety of prototyping boards are available to jump-start projects.  Often a great choice for one-off or small quantity projects.  A few useful ones are presented here.

Relay Boards

Real-world applications often require controlling external devices.  Electronics Salon on ebay has a nice series of 2, 4, and 8 channel relay boards, controlled by logic-level inputs.  The boards feature drivers so don't draw much current from the micro, and can be ordered with either 5V or 12V relays.  Search on "relay module" to find these great boards.

Dallas One-Wire DS18B20 Temperature Sensors

Dallas One-Wire protocol components are handy for distributed measurements - a number of sensors can used on a single cable.  The DS18B20 is a commonly used temperature sensor.  Sure Electronics offers a temperature probe with the temperature sensor potted in a stainless steel casing.  The cost of this probe from Sure is scarcely greater than the cost of the DS18B20 from Maxim.  Note that the pinout of these sensors does not correspond to the TAP-28 pinout, although the contacts may be repositioned in the housing if desired.

Sure does have a web site but the best bet is to find the sensor on ebay by searching for "DS18B20"

Header Connector Jumpers

Development Board

The TAP-28 has limited on-board peripherals for those experimenting with PIC microcontrollers and learning about programming.  A variety of development boards are available to aid studies.  A few cost-effective boards are shown below.

Sure Electronics PIC18F4520 Demo Board

Offering super value, the PIC18F4520 Demo board includes a 2x16 character LCD, a 4-digit seven-segment display, a LM-75 I2C temperature sensor and a host of other features.  It's a great platform for software development.

Search for "PIC18F4520 Demo" on ebay to find this board.

Read reviews of the board here and here.