外文翻译---嵌入式单片机网络测控系统的设计-单片机(编辑修改稿)内容摘要:

stem。 in thermostat mode, user need to program to constitute the temperature control system. Two working mode can transform each other. The AT89C51 chip converts control mands and data received by serial port into 1wire signal for DS1821 , then send to DS1821, thus it acplished control DS1821. The DS1821 return 1wire signal of status value or temperature value. The AT89C51 recognise and convert these signal and send out from the serial port. The W78E58 microcontroller uses MHz crystal oscillator, as figure 3 shows. The powerup reset circuit posed by C1 and R3. The preset switch S11 is used to set entering setting status or normal working status when the system power up. The ( label RESET) connects to RESET pin of work card, and acplishes the reset funtion to the work card. Figure 3. W78E58 MCU circuit diagram The RAM memory 62256 connects to MCU with typical circuit. The 74HC373 is used to latch the low 8 bits address bus. The 62256 address range is 0x0000~ 0x7FFF. The SDA and SCL pins on external memory AT24C02 connect to MCU and pins respectively. The W78E58 software simulate the timing of I2C bus on , pins, thus it acplished read and write operations of AT24C02. The write protect pin connect to lowlevel, does not perform the write protect. While connecting A0, A1, A2 pins to GND, read and write address is respectively 0xA1 and 0xA0. The serial interface chip MAX232 pins of CPUTXD and CPURXD connect to MCU pins of TXD and , RXD respectively. This system can use any ISA interface work card which is patible with NE2020. The new work card can be set with their own set program on puters in order to meet the basic requirements of the embedded work system. The specific procedures are as follows: (1) Enter into the msdos operating systems, run work card set program. (2) According to the table 1 set the work card. (3) Choose YES to exit the setting program and these settings take effect. Pull out this card from the puter, insert it into the system board. Parameters Custom Settings The work system provides custom function of initialization parameters. The user can flexibly and conveniently set all system initialization parameters by using super system tool of Windows operating system. Firstly, connect the system serial port to a puter serial port, here is COM2. From the “start” menu, select program attachment munication, lauch hyper system, and there is a connection describe dialog box, waiting to input a connection name, enter setup and click the ok. Then a “connect to” window appears, at connection with place, choose COM2 which is connection port between system and puter and click ok. Then set the munication parameters for COM2 in COM2 attribute setting window. Click ok to enter the hyper system main interface. In order to get better result in the process of configuration parameters, it is necessary to set “hyper system”more detailedly. Click properties button on the toolbar, open “properties” dialog box. Choose Settings, click ASCII code set button in ASCII Settings window. After finishing these settings the system return to main interface, hyper system in a waiting connection status. Put preset switch S11 to OFF position, the green light display serial port data transmission and the red light display the work data transmission. 5 The Program Design Essential and Application Of Network Sense System MCU。
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