Keywords: iButton family overview, iButton family guide, iButton Standards, 1-Wire Standards, iButton mechanical specification, 1-Wire electrical specification
APPLICATION NOTE 937
Book of iButton® Standards
By:
Bernhard Linke, Principal Member Technical Staff
Jan 16, 2002
Abstract: An iButton is a chip housed in a stainless steel enclosure. To keep the cost of access low, the electrical interface is reduced to an absolute minimum, i.e., one data line plus ground (also called 1-Wire®). The energy needed for communication is "stolen" from the data line ("parasitic power").
In some ways the family of iButton devices vary greatly. There are iButtons that contain only a unique registration (ROM) number and there are iButtons that have read/write memory, real-time clocks, and temperature loggers. However, with respect to mechanical and network level commands all compliant readers can read them.
This document explains all of the relevant specifications for mechanical, electrical, and protocol for the iButton family of products. Most of the information is also applicable to the 1-Wire products not in the iButton package.
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APPLICATION NOTE 937: Book of iButton® Standards