Nuclear signal input LCD processing display unit based on Proteus

Abstract: Proteus can realize single-chip microcomputer simulation, provide software debugging function, and support third-party software compilation and debugging environment, such as Keil C51 uVision2. This design uses 89C51 single-chip microcomputer as the control unit, establishes the coordinates of dot matrix LCD12864 and lights up the matrix points, so as to realize the synchronous display of nuclear signals on dot matrix LCD12864 and character LCD1602. The simulation was carried out in Proteus software and the expected results were obtained.
Keywords: Proteus; nuclear signal; single-chip microcomputer; LCD; display

Proteus ISIS is a simulation software developed by Labcenter, a British company, which integrates single-chip microcomputer and SPICE analysis. It is extremely powerful. The features of this software are: it realizes the combination of single-chip microcomputer simulation and SPICE circuit simulation; it supports the simulation of mainstream single-chip microcomputer systems; it has powerful schematic drawing function; it provides software debugging function, and it also supports third-party software compilation and debugging environment, such as Keil C51 uVision2 and other software.
The nuclear signal is the output signal of the nuclear radiation detector. Since its signal is relatively weak, it must be amplified by the preamplifier and amplifier before processing. Most of the existing nuclear signals displayed on LCD are numerical displays, and the changes of nuclear signals cannot be observed intuitively. This design uses the Proteus software to synchronously display nuclear signals through dot matrix LCD12864 and character LCD1602, and provides a basis for the multi-screen synchronous display of multiple nuclear signals.

1 Hardware Design
The hardware block diagram of this design is shown in Figure 1. The movement of the sliding rheostat is used to realize the change of the input signal, which is used to simulate the nuclear signal as input; ILC2543 performs analog-to-digital conversion on the input signal; AT89C51 is used as a microprocessor to realize control, and the change curve of the nuclear signal is displayed on LCD12864, and real-time digital display is performed on LCD1062. Among them, KS0108 and HD44780 are used as controllers of LCD12864 and LCD1602 respectively.

TLC254 3 is a 12-bit serial analog-to-digital converter from TI, which uses switched capacitor successive approximation technology to complete the A/D conversion process. 12864 is a graphic dot matrix LCD, which is mainly composed of row driver/column driver and 128x64 full dot matrix LCD. It can complete graphic display and can also display 8x4 (16x16 dot matrix) Chinese characters. 1602 character LCD is divided into two types: with backlight and without backlight. Its main technical parameters and pin functions can refer to its manual. Most of its commonly used controllers are HD44780.

2 Software Design
This design program is written in C language. The main program flow chart and dot matrix LCD12864 curve display flow chart are shown in Figure 2 and Figure 3 respectively.

According to the pin functions of each chip, the relevant timing diagram and flow chart, the main program is written as follows:

3 Simulation in Proteus software
In order to verify the correctness of the hardware circuit and program function, simulation is performed in Proteus ISIS software. The simulation steps are as follows:
1) Select the 1602 character LCD of LM016L model and the 12864 dot matrix LCD of LGM12641BS1R model, and draw the schematic diagram corresponding to the hardware block diagram Figure 1 in Proteus, as shown in Figure 4.

2) Import the main program and the programs corresponding to the three header files into the Keil software for compilation. After success, a hex file is generated, as shown in Figure 5.

3) Import the generated hex file into AT89C51 of Proteus ISIS to realize the connection between hardware and software, as shown in Figure 6.
4) Click the button to start the simulation, adjust the sliding resistor to simulate the change of the nuclear signal, and the simulation diagram is shown in Figure 7.

4 Conclusion
By adjusting the sliding rheostat in Proteus ISIS, the function of synchronously displaying the input analog signal change curve and real-time value on the dot matrix LCD12864 and the character LCD1602 is realized. The correctness of the hardware circuit and software design of this design is verified, that is, the real-time display function of the nuclear signal can be realized. This design fails to realize the nuclear signal processing display of multi-channel input and multi-screen LCD display, which needs further research.