【正文】 在綜合全國各地公考模擬試卷優(yōu)點的基礎上 ,特意編制一套緊貼 2021 年湖南公考命題精髓的“考前 預測卷 ”,有利于考生提前適應公考試卷的難度、區(qū)分度并有利于提高考生考前心理適應共 4 頁 第 10 頁 度。 考試百科還提供考試咨詢、培訓服務，依托于揚格考試研究院 —— 以考試研究為核心、以提供考試服務為目的的專業(yè)考試研究機構(gòu)，考試百科積累了優(yōu)厚的師資和豐富的教學經(jīng)驗。 After that 48 bits are this DS18B20 own sequence numbers, and these 48 sequences number is only one in the whole world, finally 8 bits are the front 56 cyclical redundancy check code. So use the 64 bits serial number we can divide each DS18B20,and we can meets many temperature sensors of DS18B20 on one1Wire Bus. According to DALLAS Semiconductor Corporation39。 The twisted pair wire (coaxial cable) transmits the medium separately to meet to the chip of PCA82C250 pins CANH, CANL. Considered the scene has various disturbance, the high speed light isolation ponents (6N137) are added between the CAN controller SJA1000 and the PCA82C250[4]. The pitch point hardware design 共 4 頁 第 7 頁 The pitch point mainly includes the CAN Bus interface, the control module of the air gate of airconditioning system and temperature sensor DS18B20, the system structure like figure 3 shows. The DS18B20 is DALLAS Semiconductor Corporation39。 In this foundation, the console set each pitch point temperature value setting for every room, and realize the entire building temperature realtime examination, by the LCD demonstration examination result, the unusual situation is reported by the warning through speech Property by the signal and controlled through the gate of air conditioning?s system , realization energy conservation goal. The system design goal is measure and control temperature in a building each room, because measured the temperate point and control point is dispersion, therefore the system uses the distributional structure, The console is connected each part of control pitch point distributing in the building through the CAN Bus. System structure diagram like figure 1 shows The console hardware design The AT89C52 MCU is the primarily controller in console, It connects with the 共 4 頁 第 6 頁 warning module, the memory module, the clock/calendar electric circuit and the keyboard module. its structure drawing see Figure 2. The control pitch point also is controlled by the MCU, connected temperature examination module and the CAN Bus interface module. The system has used the AT89S52, it is a section low power chip that is produced by ATMEL Corporation, has 4 KB insystem programmable (ISP) FLASH memory integrated. The scene programming debugging and the system function changing is much conveniently flexible, using AT89S52 to take the system the master controller. When system normal work. The console send a definite control temperature value to a designate pitch point Distributed in the building through the CAN Bus. The pitch point receive the console?s orders and read the temperature detector DS18B20 temperature value distributed in each room through 1Wire bus, transmits each room temperature data and the number of room to the console through the CAN Bus. According to the definite temperature value which receives from console control the air gate of airconditioning system in each room. After receive the data a pitch point send to, the console reads the time from realtime clock/calendar chip PCF8563 through the I2C Bus, with the data which just received store to the memory AT24C128, then process each room temperature value. When the value achieve the data which is established from keyboard in advance, the console output warring to the alarm circuit on reports the alarm. Meanwhile the room number, the time and the temperature value delivers the LED display circuit to display. Every room alarm temperature value is established through the keyboard input module, the console process value and stores in the memory co