The Collection And Storage Of Physiological Signals System Based On STM32

The collection and storage of physiological signals system based on STM32,which as a portable remote monitoring system, saves physiological signals data (heartrate, pulse rate, respiratory rate, SpO2, blood pressure, body temperature and so on)by real-time or in the event of an alarm. It can be used to review and analyze bymedical researchers. This system uses STM32F103microcontroller as the maincontrol chip and processes the collected data. Then it stores the data in the SD card inthe form of a document. Meanwhile, it has the corresponding file managementfunctions.This paper mainly completed the following work:Firstly, it does the whole outline on the SD card and FATFS file system. At thebeginning the paper introduces the interface, command format and protocol of SDcard. Then studies the Fatfs file system’s design thought and organization structure,which is often used in the small embedded systems.Secondly, the paper introduces the realization of data receiving and storagesystem. It does a detailed study of the software design and hardware design of thesystem. The system hardware platform is developed using STMicroelectronics32bitmicro controller–STM32F103RE–as main control chip. The DS1374real-time chipprovides the time. And SD card interface is used in SDIO mode, so as to ensure thestorage speed. The software of the system is based on MDK integrated environment.It is designed in modules, including data acquisition module, low level disk I/Omodule, Fatfs file system module, real-time clock module and SD card applicationmodule. The data acquisition module mainly through USART to receive the humanphysiological signal data. The low level disk I/O module is mainly responsible fordriving the SD card, including power on, initialization, getting card information, single and multiple block read/write operation. The Fatfs file system module is abridge between low level disk I/O module and SD card application module, and itstransplantation process is very important. The real-time clock module provides thetime for the system, in order to name file by the real time. SD card application modulemainly provides interface functions, such as creating and read/write files, delete files,rename files and format SD card,etc.. Then the paper introduced the system powercontrol. The system mainly from three aspects: micro controller, SDIO bus and the SDcard to reduce power consumption.Finally the paper introduces the file protocol when storing data. It includes fileformat and how to store the.dat and.set files. Also it includes file management andhow to deal with emergency situation. The.dat and.set files are located in theDATA and SET directory. In DATA directory, the system creates a new subdirectoryevery day and named it by current date. This has two advantages: first, file traversal ismore convenient, it can identify the earliest or latest file or directory quickly. Second,file deletion is more convenient. When the remaining space of the SD card is notenough, it can directly deletes all the files in the earliest directory. When emergencysituation occurs, such as sudden power off or SD card removed, because this designhas minimized the critical region, the data damage down to the minimum.