Choosing the Right 1-Wire Host for Your Embedded Application

introduction

The 1-Wire bus is a simple signal transmission circuit that enables half-duplex bidirectional communication between a master controller and one or more slave devices through a shared data line. Power and data communications are carried over a single data line, making 1-Wire devices unmatched in functionality and reducing interconnections between systems. 1-Wire devices provide memory, mixed-signal, and security authentication functions through a single-contact serial interface. Typical applications of 1-Wire devices are as follows: identification of print cartridges or medical consumables; calibration and control of rack cards; identification and authentication of printed circuit boards, accessories and peripherals; intellectual property protection, anti-cloning, and security function control.

When using 1-Wire technology, signals need to be sent through the 1-Wire master to identify the devices on the bus and communicate with them. There are many ways to build a 1-Wire host. This article discusses hosts for embedded applications, including small networks with a radius of no more than 1 meter and no more than three to five 1-Wire slave devices. When designing a large 1-Wire network or with a large number of slave devices, refer to application note 148: " Guidelines for Reliable Design of Long-Term 1-Wire Networks ."

The 1-Wire master mentioned in this article is compatible with host circuits powered by 3V to 5V. The 1-Wire circuit does not involve protocol conversion and is also suitable for masters operating with voltages below 3V, in which case a level converter is required between the master and the 1-Wire slave. Application Note 4477: " 1-Wire® Bidirectional Level Translator (1.8V to 5V) Reference Design " describes such a circuit. The R _PUP in this article corresponds to the R4 in application note 4477.