Research Of ECG Signal Acquisition System Based On USB Technology

With the movement of the social and the progress of technology, the people's healthy concept,healthy fashion and approaches are deeply changed. In our country, hemal disease of heart and brain is a high-occurred disease. But most hospitals have few cardiogram detecting equipment, and these equipment can not be moved easily and have a too high price, so the equipment can not satisfy the needs of the market. In order to satisfy the needs and depreciate the iatrical cost, we need a kind of cardiogram detecting system which can communicate with the PC as to use its powerful calculation. The system adopts the USB technique, which has the characteristics of bus offering power, easily extending, flexibly using and pluging and playing, and can effectively solve the problem of communication and transmition with the PC and system.The paper expounds the design and realization of ECG Signal Acquisition System based on USB technique. It consists of the design of the Analogous circuit of ECG Signal Acquisition, the choice and utilizations of the Micro controller and USB interface chip, connection of circuit, the detailed design of device firmware, data acquisition stored program, device driver program and application program,etc.This ECG Signal Acquisition System strictly follows USB 1.1 protocol. It utilizes the enhanced 16bit-MCU MC9S12D64 (made by Motorola Corporation) as the microcontroller to sample the ECG signals, adopts PDIUSBD12 chip (made by Philips Corporation) with parallel buses as the USB interfacing device and realizes the system power supply through USB interface. In this system, the microchip system focuses on sampling signals and data communication; PDIUSBD12 fulfils USB interfacing comunication; and the PC completes data receiving, preservation,display and other functions. The software design adopts C language to compile data sampling program and the program of USB interfacing chip's protocol processing and data transferring. The Application program of upper computer is compiled with C++ Builder.This data acquisition system represents the trend that medical instrument is miniaturized with easy operation and lower cost,which is specially suitable for family use. It also provides a novel, convenient and reliable solving project for data acquisition.