This paper introduces digital temperature sensor DS18B20’s function，structure the principle of temperature measurement and the communication protocols of 1-wire bus as well as its application in multiple temperature measurement system . With the high accuracy and good exchange capacity, this sensor can code the temperature data directly and transmit information through 1 - wire bus. So communication becomes more convenient, the transmitting distance becomes more far and the anti-jamming ability becomes more high. DS18B20 is a digital temperature sensor of single bus, which contains temperature measure and A/D conversion and exports digital signal directly with a simple interface with SCM. This paper presents the hardware and the C51 design of the temperature measure and control system based on DS18B20 and AT89C51.This system has many outstanding characteristics such as simple lead-distribution, compact structure, light weight, high anti-jamming ability, convenient expand and so on. Therefore it becomes a perfect choice for temperature measurement system.
Key words: digital temperature sensor； 1-wire bus； communication protocol；DS18B20； AT89C51；SCM
