Simulation Design of Single Chip Microcomputer Real-time Clock Based on Proteus

Proteus is one of the most advanced MCU CPU and peripheral circuit simulation tools. This article introduces the characteristics of the MCU simulation software Proteus, and introduces the process and method of circuit design and simulation using Proteus in detail with the example of real-time clock circuit, aiming to provide a good learning platform for MCU enthusiasts and technicians.

Single-chip microcomputer technology is applied to all walks of life and is a practical intelligent control technology. The development of single-chip microcomputer technology has greatly promoted the rapid development of electronics, communications, computers, mechatronics and other industries, and has become a popular technology in current teaching and scientific research. This article introduces a new type of single-chip microcomputer simulation software Proteus in detail, which can be used to realize the simulation of many port-oriented and peripheral device expansion control experiments in single-chip microcomputer teaching, improve teaching effects, and further shorten the distance between teaching and engineering practice.

1 Introduction to Proteus

ProteusISIS is a circuit analysis and physical simulation software developed by Lacenterelec-tronics in the UK. It has a wide range of applications, including PCB plate making, Spice circuit simulation, microcontroller simulation, and simulation of ARM7/LPC2000. Proteus is mainly composed of two modules, ARES and ISIS. ARES is mainly used for the design of printed circuit boards (PCBs) and their circuit simulation, and ISIS is mainly used for the design and simulation of schematic diagrams. It runs on the Windows operating system and can simulate and analyze (SPICE) various analog devices and integrated circuits. The characteristics of this software are: ① It realizes the combination of microcontroller simulation and SPICE circuit simulation. It has simulation of analog circuit simulation, digital circuit simulation, and simulation of systems composed of microcontrollers and their peripheral circuits; there are various virtual instruments, such as oscilloscopes, logic analyzers, signal generators, etc. ② It supports the simulation of mainstream microcontroller systems. The types of microcontrollers currently supported are: 68000 series, 8051 series, AVR series, ARM series, PIC12 series, PIC16 series, PIC18 series, Z80 series, HC11 series, and various peripheral chips. ③ Provide software debugging function. The software simulation system has debugging functions such as full speed, single step, and breakpoint setting. At the same time, you can observe the current status of various variables, registers, etc.; it also supports third-party software compilation and debugging environments, such as KeilC51uVision2 and other software. ④ Has powerful schematic drawing function. In short, this software is a simulation software that integrates single-chip microcomputer and SPICE analysis, and its functions are extremely powerful.

Taking the microcontroller real-time clock circuit as an example, the following introduces the process of designing and simulating the microcontroller real-time clock circuit using Proteus.

2 Hardware circuit diagram design

The hardware of the real-time clock circuit is mainly composed of AT89C51 single-chip microcomputer, clock chip DS1302, digital tube display driver chip MAX7219 and other components. The real-time clock circuit schematic is shown in Figure 1.

After running ProteusISIS, the main window interface of the program appears. Click the Component button in the component toolbar on the left side of the window with the left mouse button, and then click the PickDivices. button in the component selection area on the left side of the window. The PickDevices window pops up. After clicking the MicroProcessorICs item in the Category column, various types of CPU devices will appear in the Results column. After finding AT89C51, double-click it, and AT89C51 will be added to the component list area on the left side of the current window. Use the same method to add DS1302, MAX7219, digital tube, crystal oscillator, and multiple resistors and capacitors to the device list area. Then click the devices in the list area in turn, click the left button to put them in the drawing area, right-click to select the components, and edit their properties. After reasonable layout, connect them. After all the wires are drawn, add the power and ground symbols, and the drawing of the schematic is completed. Save the design file in the C: ProgramFile Lacenter Electronics Proteus7 Professional clock folder, and the file name is clock.DSN.

3 Software Design and Implementation

The main functions of the software of this real-time clock circuit include the setting of the clock chip DS1302 and the reading of the time, and the digital tube display driver chip MAX7219 driving the time display, etc. The software is written in assembly language. After editing in the WAVE3.2 integrated debugging software, it is saved with the file name DS1302.asm and compiled to generate a hexadecimal target file DS1302.hex. It is also saved in the C:ProgramFileLacenterElectronicsProteus7Professionalclock folder.

4 System simulation analysis

After the circuit schematic is designed in ISIS and the system software is compiled into a .hex file, the virtual simulation of the real-time clock circuit can be performed. In the schematic diagram of ISIS, right-click AT89C51 to select it, then click the left button to open the EditComponent dialog box of AT89C51, select the file DS1302.hex in the ProgramFile option, and click the OK button to complete the simulation settings. Click the Run button of the simulation button below ISIS, the system starts running, and the current time is displayed in real time.

5 Conclusion

Through the example of using Proteus software to realize the simulation design of single-chip real-time clock circuit in this paper, it can be concluded that introducing Proteus software into single-chip computer course for auxiliary teaching is a reform of teaching method. It is a comprehensive application of virtual simulation technology and computer multimedia technology, which is conducive to promoting curriculum and teaching reform, and is more conducive to cultivating students' innovative quality and creativity. At the same time, Proteus's constantly improving functions and powerful simulation capabilities are loved by more and more designers, and it has also been gradually promoted in student electronic design competitions.