Design of Serial Communication Based on Single Chip Application System
1 Introduction In the power imaging equipment detection system of infrared imaging technology, based on the application system of AT89C51 single-chip microcomputer, the non-contact infrared thermometer with model number 3iLRL3 of American Raytheon Company is adopted. The thermometer uses the RS232C serial communication standard interface, which is common in many communication devices. At present, direct serial communication with the PC is also an RS 232C interface. Although the RS232C performance index is not very good, it still has broad market support. It is easy to exchange information between two digital devices to achieve full-duplex data transmission, and the hardware cost is low. And good versatility. 2 Serial communication hardware design Serial communication refers to the use of a data line to sequentially transmit data bit by bit, with each bit of data occupying a fixed length of time. It only needs a few lines to exchange information between systems, especially for long-distance communication between computers and computers, and computers and peripherals. In the developed system. The infrared thermometer will detect the working and environmental temperature of the power, and pass it to the single chip through the RS 232C serial port. At the same time, the online configuration of the detection device is controlled by the single chip. The control circuit composed of a single-chip microcomputer is the data transfer station, and the upper PC computer downloads the online working configuration of the infrared thermometer. Here, the serial communication interface between the microcontroller and the PC is still RS 232C standard communication. The AT89C51 microcontroller has only one serial port, which will solve the problem of another serial port expansion. The system uses the universal serial communication interface chip 8251A to expand. The hardware circuit of the serial communication of this system is shown in Figure 1. In the system, infrared thermometer and PC have two serial ports, and 89C51 has only one serial port. The programmable universal serial interface chip 8251A is used to communicate with the upper PC. Because the chip select end CS of the 8251A serial chip is connected To Y2 of 74LS138 decoder. Therefore, the port address of 8251A is OA000H, RXCLK and TXCLK receive and transmit clocks are connected to T1 port of 51, and use T1 as the baud rate generator [1]. 3 Software design AT89C51 is a low-voltage, high-performance CMOS 8-bit microprocessor with 4K bytes of FLASH memory (FPEROM—Flash Programmable and Erasable Read Only Memory), commonly known as a microcontroller. AT89C2051 is a single-chip microcomputer with 2K bytes of flash memory programmable erasable read-only memory. The erasable read-only memory of the single chip microcomputer can be erased repeatedly 1000 times. The device is manufactured using ATMEL high-density nonvolatile memory manufacturing technology and is compatible with the industry-standard MCS-51 instruction set and output pins. Due to the combination of multi-function 8-bit CPU and flash memory in a single chip, ATMEL's AT89C51 is a highly efficient microcontroller, and AT89C2051 is a simplified version of it. The AT89C microcontroller provides a flexible and inexpensive solution for many embedded control systems. Main features: · Concurrent with MCS-51 128 & TImes; 8-bit internal RAM · 32 programmable I / O lines · Two 16-bit timers / counters · 5 interrupt sources · Programmable serial channel Low-power idle and power-down modes · On-chip oscillator and clock circuit The serial port of the infrared thermometer is directly connected to 89C15 through MAX232, so the infrared scanning sensor head scans the power equipment according to the given scanning strategy, reads the temperature scanning signal, and performs the maximum, minimum, average and abnormal rejection processing. Record the scan time and temperature value and wait for the PC command. Send data to the PC, the flow of sending data is shown in Figure 2. The infrared sensor controls the status of the power equipment through the online work configuration downloaded by the PC, and the flow of receiving data is shown in FIG. 3. The serial communication between the SCM and the PC passes 825lA, so the 825lA is initially programmed in the communication program, the serial port communication mode is set, and the communication protocol is determined. These are the key points of communication programming. The FirstPower CFPS(2V) and LFPS(6V/12V) series stationary batteries (Opzs Battery) are the newly products which were developed at the end of 2005. Storage Power Opzs Battery,Solar Storage Battery Opzs Battery,Opzs Battery Firstpower Tech. Co., Ltd. , https://www.firstpowersales.com
RS-232 is EIA (Electronics Industries AssociaTIon) level. The signal level uses negative logic, logic "1" = one 12V, logic "0" = + 12V. This is incompatible with the TTL signal level of the microcontroller, so the serial ports RXD (serial receive port) and TXD (serial transmit port) of the RS232C and 89C51 microcontroller cannot be directly connected, and a converter needs to be connected between the RS232C and TTL circuit Perform level conversion. Output RS 232C level. MC1489 is to receive RS 232C level and output TTL level. The inconvenience of this level conversion interface is that it requires ± 12 V working voltage and large power consumption. Not suitable for low power consumption systems. 
The performances meet the standard DIN40736 and IEC60896-21...Characteristics Positive plate: It is a tubular plate that can prevent the active material from falling off. The grid of positive plate is Pb-Sb multi-alloy
Separator: With the combined application of porous rubber and porous PVC, the separator has a high porosity and good corrosion-resistance
Acid-proof bolt: It is of a special shape of funnel having the function of filtering acid smog and retarding flame. It can measure the density and temperature of electrolyte.
The design life is more than 20 years
Ensuring sufficient electrolyte for battery discharge