PCF8591 is a monolithic, single supply, low power,8-bit CMOS data acquisition devices. PCF8591 has four analog inputs, one analog output and a serial I2C bus interface. PCF8591 the three address pins A0, A1 and A2 can be used for programming the hardware address, allowing access to eight PCF8591 devices on the same I2C-bus without additional hardware. Input and output on PCF8591 device address, control and data signals are by-wire bidirectional I2C bus serially transmitted. Up to eight PCF8591s can be connected via the I²C bus. Control and data signals are transmitted bi-directionally via the I²C bus.