Introduction
This application note describes how to develop a temperature sensor application using the ST LM135 temperature sensor. Application development was done on a Raisonance REva board. The Raisonance REva board is a universal board with several useful features for application development. It has been designed for quick and easy evaluation of a wide range of microcontrollers. This application uses the ST72325 microcontroller, which is interfaced to REva using a daughter board.

The main components required for the development of this application are:
■ ST LM135 temperature sensor
■ ST72325 microcontroller
■ ST24C02 I2C EEPROM
■ ST3232 communication interface
   Some of the useful features of the REva board are:
■ Digital and analog I/O evaluation features including on-board LEDs, buttons, switches,
   external analog connector, temperature sensor and potentiometer
■ On-board I2C EEPROM and bus extension connector
■ On-board RS232 driver and DB9 connector
■ SPI, CAN and USB connections (depending on the target device)
■ Embedded RLink for in-circuit debugging and in-circuit programming VDD settings for
   1.8 V, 3.3 V, 5 V microcontrollers
■ USB powered, no external power required