Simple verification code generator for 51 single chip microcomputer experiment

well ！！ Long time no see , With all of you
Will you miss the pig ？
Um. … Why not ？
ヾ(≧ ▽ ≦)ゝ

Preface ：

This paper is an experiment done by autonomous learning , There may be many deficiencies , Please point out ！！

One , Abstract

This comprehensive experimental report is written according to the topic given by the experimental subject , The subject content is the verification code generator . Mainly through the use of the single-chip microcomputer serial communication learned this semester 、 Liquid crystal display LCD1602、 Serial port interrupt system 、 The related content of external interrupt realizes a slave host （ Input in the virtual terminal ） Send to the slave 6 Verification information of digit number or letter verification code , After receiving through the sub machine, it will be in LCD1602 It shows that . In order to verify whether it is received accurately , Here we also design a LCD1602 The LCD displays the content sent on the virtual terminal , To check whether the sub machine receives correctly . This experiment simply simulates the sending mechanism of verification code in digital communication , The following is the whole content of the experiment .

Two , Purpose

Through this experiment to improve this stage of single-chip learning , By the way, make a summary , Mainly the content of serial communication , Prepare to touch the embedded , That is to prepare for the following study .

3、 ... and , Functional specifications

Enter a 6 A letter or number of digits or a combination of numbers and letters , The host LCD1602 The input data is displayed on the LCD screen , Press the key to send the data to the slave , In the sub machine LCD1602 The data is displayed on the display . From the perspective of verification code generator, it is that the host sends verification code to the slave , The verification code received by the sub machine can match the host , Check whether the verification code is consistent .
Function description of each part ：
（1） host AT89C51 And sub machine AT89C51:4k byte Flash Flash memory ,128 Inside the byte RAM,32 individual I/O Mouth line , Two 16 Bit timing / Counter , One 5 Vector two-level interrupt structure , A full duplex serial communication port , On chip oscillator and clock circuit . meanwhile ,AT89C51 Can be reduced to 0Hz Static logic operation of , It also supports two optional power-saving working modes of software . Idle mode stops CPU The job of , But allow RAM, timing / Counter , The serial communication port and interrupt system continue to work . Save by power failure RAM The content in , However, the oscillator stops working and all other components are prohibited from working until the next hardware reset .
（2）LCD1602 Liquid crystal display ： The liquid crystal in the form of dot matrix is composed of M×N It consists of two display units , hypothesis LCD The display has 64 That's ok , Each row has 128 Column , Every time 8 Columns correspond to 1 Bytes of 8 position , That is, each line consists of 16 byte , common 16×8=128 A point of . On the screen 64×16 A display unit and a display unit RAM District 1024 Bytes correspond to , The content of each byte corresponds to the light and dark of the corresponding position on the display screen . For example, the brightness of the first line of the display screen is determined by RAM District 000H~00FH Of 16 The contents of bytes determine , When （000H）=FFH when , A short bright line appears in the upper left corner of the screen , The length is 8 A little bit ; When （3FFH）=FFH when , A short bright line appears in the lower right corner of the screen ; When （000H）=FFH,（001H）=00H,（002H）=00H…,（00EH）=00H,（00FH）=00H when , At the top of the screen, a message from 8 A bright line and 8 A dotted line composed of dark lines . This is it. LCD Basic principle of display .lcd1602 Mainly used to display numbers , Letter , Graphics and some custom characters . Because of its simple display control and high cost performance , It is widely used in electronic instruments , The refrigerator , Air conditioner , Automotive electronic instruments and other equipment .
（3） Virtual terminal ： share 4 Terminals , among RXD It is the data receiving end ,TXD It is the data sender ,RTS Send a signal for the request ,CTS To clear the transfer , It's right RTS The response signal .Proteus The virtual terminal provided is equivalent to the dual functions of keyboard and screen , It eliminates the simulation model of the upper computer system , When users use the serial communication between MCU and host computer , Directly from the virtual terminal through RS-232 The model sends and receives data asynchronously with the MCU . Here, only the function of sending data by virtual terminal is used .

Four , Hardware circuit design

Name of components used ：AT89C51、BUTTON、LM016L、POT
In this experiment, we use AT89C51 Of I/O Interface P2 Connect LCD1602 Monitor , Thus, the received data is displayed in LCD1602 On the screen . The host AT89C51 Upper RXD Connect... On the virtual terminal TXD, So as to receive the data input by the virtual terminal , On a host computer TXD Connect the RXD Send data to the slave . Key connection P3^2 mouth , Use external interrupts 0 control .

5、 ... and , Programming

（1） The first thing to talk about here is LCD1602 file , We all know that learning SCM , In learning this part , The teacher will give the corresponding LCD1602 The header file , The header file is relatively perfect . But here , We need to write the corresponding content by ourselves , Because what I need to achieve here is input by the virtual terminal, so I'm writing .c When programming, you should put the content of the defined function into the host and sub machine , You can't directly use what is given on the Internet or by teachers LCD1602 The header file , It needs to be changed .
First, let's look at the original header file ：

open intrins.h You can see the commands in the header file , We can quote the header and tail to indicate that there is this header file , You can define the commands you need , In this way, you will clearly know the function commands and variables you need to use . Here's the picture

After defining the required variables, you can write LCD1602 Of .c The file , as follows ：

（2） The host .c file
from main Function start ：

from main The function shows , Here are several functions ：
1, Window function

effect ： Define the working mode of serial port 1 And regular working mode 1, Set the baud rate to 9600（ You can design it yourself ）, Turn on the total interrupt and serial port interrupt .
2, External interrupt switch function

effect ： Open external interrupt （ Key control data transmission ）
3,LCD1602 Initialization function

4, Sending function

effect ： When the key is pressed, the data is sent to the slave
5, Show function

（ Attention should be paid to the above analysis , There is no repeated parsing here , You can ask me if you don't understand ）
effect ： Display data on the display .
（3） Host all .c file





This is the simple function of the host of the verification code sending mechanism
（4） Subprogram


The subroutine is simpler than the host , But they are all similar , Don't do too much parsing .

6、 ... and , Simulation

Here's a reminder ： The baud rate of the virtual terminal needs to be designed according to the baud rate set by itself .
All right. ！ Treasure children , That's all about the experiment , I hope it can help you to 51 SCM has a further understanding

If this article is helpful to you or you like small bloggers , Remember to like comments and pay attention ！ Or you won't find me o(▽)q
Support small bloggers a lot
Let's cheer together