A single-wire interface can be used for serial protocol applications, such as I2C and SPI buses. It provides a smallfootprint communication channel between a controller and low-cost components on the board such as temperature sensors. Such communication channels usually do not require high speed. The protocol should be simple; using few resources in the controller.
As its name suggests, this bus protocol uses one wire to communicate with a master controller, usually a microprocessor. This reference design implements the Single-Wire Controller in a PLD. The initialization procedure and all data transfers are implemented in the PLD to offload the tasks of the microprocessor. The task of the microprocessor is reduced to reading and writing of the registers in the master controller through the WISHBONE bus. The Single-Wire Controller can be used in various applications. This design uses a single-wire interface to read/write a digital-output temperature sensor.