A microcontroller based data acquisition system with USB interface

Abstract

A wide-spread operation founded in the monitoring, control and command applications is the data acquisition. The data from the external world is read, processed, used for decisions and, eventually, memorized by a digital system. The digital system may be a PC with dedicated interfaces or microcontroller based system. This paper describes a data acquisition system with USB inteijace. I t is based on the P89C51RD2 microcontroller. The USB interface is achieved by an ISPI181 circuit and the data acquisition is done by two TLCO820 analog digital converters. The software executed by the microcontroller was divided in 5 levels: the 0 hardware abstraction level, the 1 hardware abstraction level, the interrupt service routine, the standard USB requests level and the main loop, each one with specific operations.