| This article introduces the design and development of one kind of wireless home monitor system which is designed over the USB interface based on Microsoft Windows 2000 platform of personal computer. The intention of the design is to introduce the technology of monitor to the family , to make the development of the home monitor technology, to improve the medical level in the family. A lot of new technologies are introduced into this article ,such as the wireless transmit and the universal serial bus . The type of wireless transmission detaches the part of data acquisition from the part of data processing in order to improve the monitor system upon the practicability and security for the person. The Universal Serial Bus is a kind of newer bus interface's criterion than other buses in the computer's technology. In the design, the Universal Serial Bus is used as the interface between the system and the computer that makes the design possess a lot of features , such as easy operation, plus and play, none of external power , and need not to install. The accomplishment of the design helps the development of the home monitor technology.To the hardware, the design is composed of two parts: the one is the part of data acquisition and wireless data sending and the other is the part of wireless data receiving and the interface circle of Universal Serial Bus. To the functional model, the design is composed by the data acquisition, the wireless data transmission , the interface of Universal Serial Bus, the device's driver and the application.The function of the data acquisition is to check up the body and acquire the data of the physiological signals, and to transmit the datainto digital signals for the part of wireless sending . In the design the main work is to measure EGG and draw it on the computer. The preamplifier is the INA128 that is a kind of low -power, precise, instrumented product which is produced by Burr- Brown Company in the circle. The INA128 is used by left leg's driver circle and the aims are to enhance the CMRR and reduce the disturbance of 50Hz. The part of A/D transmitting chip is the ADC0809 which have a eight - channel transmitter, a eight - bit A/D transmitter and the logical control by microprocessor.The function of the wireless data transmitting model is to detach the part of data acquisition from the part of data processing. This kind of design makes the system use easily and enhances the security for the human body. This model uses the TX100 and RX100 which are a kind of ASK wireless data transmitting models and are produced by HRH company. They work on 433. 92MHz which need not apply for the wireless license and their transmitting velocity is 4. SKbps. Their hardware interface's circle is simple and they could directly line on the serial port of microprocessor and use the data frames of UART to transmit.,'The function of Universal Serial Bus interface model is to link the device to computer easily and cjuickly. This model's hardware circle uses the PDIUSBD12 which is a kind of USB interface chip produced by Philips and has 3 endpoints, and double buffering scheme. The Microprocessor Control Unit( MCU ) is AT89C52 produced by AT-MEL which has a 256 - byte flash RAM and 8K - byte programmable ROM. In order to apply the system's real - time, this design uses a kind of FIFO data memorizer , IDT7204 which need not address and the data's input and output are independent. The firmware of model isprogrammed by Keil C51 and works completely in the interrupter driver model. The data exchange between the background ISR (Interrupt Service Routine) and the foreground Main Loop is achieved by event flags and data buffers. This kind of design fully uses the hardware and enhances the system's efficiency.The device driver uses the WDM model. WDM use a kind of model of delaminating. For the USB device, it's composed of USB driver and USB functional driver. The Universal Serial Bus Driver (USED) is below the functional driver and supplied by the operating system. USBD takes charge of... |
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