TAP-28 - A “throw away” PIC board - TAP-28 Dallas 1-wire Devices

TAP-28 Dallas 1-wire Devices

Dallas 1-wire devices actually communicate over 2 wires: I/O and ground. The devices are powered by voltage on the I/O line when it’s idle. A large number of devices may be connected on the same bus, limited by cable length and the capacitance of the cable and attached devices. Consult www.maxim-ic.com for more information.

For a simple bit-bang interface, any of the 3-pin connectors will work with the addition of a single pull-up resistor (determine the value from the data sheet). An even easier solution is to use one of the lines on the I2C/SPI or UART connector that has a pull-up resistor on the board. Enable the pull-up resistor with a solder jumper and connect ground and I/O.

Requirements for the various 1-wire devices vary, and some of them may work better with or even require a power connection. The data sheet is the most reliable place to find exact requirements.