Data-acquisition System Based On MCU PIC16F877 (Terminal Section)

Based on analyzing and sumerizing basic structure, genres, and their features of data-acquisition systems, the data-acquisition system based on MCU PIC16F877 is designed, which is following the tendency of data-acquisition system and the design principle ?convenience, good practicability, high reliability, and low cost. By this data-acquisition system, 1-5V analog signal and 8-channel switch signal can be collected, and the control of switch signal and 1-5V analog signal output can be realized. Besides, with the liquid crystal display and seriel interface, the system can show the collected and processed data and fulfil the function of communication with the upper microcomputer.By means of the integrated development environment -Mplab-IDE software, assembling program and off-circuit simulation can be made. Using it with the in-circuit debugger together makes the system realize the functions of in-circuit programming, in-circuitdebugging, and downloading the assembling program, so it makes the process of designing and developing for the system easier.For the purpose of testing the function of extended ports, digital-to-analog conversion and analog-to-digital conversion, an auxiliary experiment board is made, it includes analog signal outputs, switch signal outputs, LED circuit, eight-segment nixie tubes and a digital-to-analog conversion circuit. The result of testing every section of the system shows that the system can work in going order and meet the designing demands.