The DS28EA00 digital temperature sensor from Dallas Semiconductor, Maxim Integrated Products, Dallas, TX, has a chain-mode signaling and protocol feature that automatically determines the physical location of individual sensors where multiple sensors are connected to a common 1-wire line. The device features ±0.5°C accuracy, a measurement range from –40°C to 85°C, a 64-bit internal serial number, and a 1-wire interface, which delivers power as well as communications. You can multidrop multiple 1-wire devices on the line; a 1-wire host controller uses the device's chain-mode command set to learn each sensor's serial number in the chain, starting at the first device on the line and proceeding sequentially. This sequential knowledge is directly linked to the physical location of the device in the system.