First, we will attach a complete set of template source code. The following chapter will practice the C language template program to copy this complete source code directly. The source code is suitable for the single-chip model STC89C52RC, the crystal oscillator is 11.0592MHz, and the serial port baud rate is 9600, beginners only need to modify the code from the "start of the C language learning area" to the "end of the C language learning area", other parts do not change. The copyable source code can be copied or downloaded from the original forum of the online forum. Search the name of this tutorial to find the original posted source. A complete set of template source code is as follows:
#include "REG52.H" void View(unsigned long u32ViewData); void to_BufferData(unsigned long u32Data, unsigned char *pu8Buffer, unsigned char u8Type); void SendString(unsigned char *pu8String); /*---C language learning area s begin. -----------------------------------------------*/ void Main () / / main function { unsigned char a; / / define a variable a. Unsigned int b; //Define a variable b. Unsigned long c; //Define a variable c. a=100; // Assign a value to variable a. b=10000; // Assign a value to variable b. c=1000000000; // Assign a value to the variable c. View (a); / / View the first number a on the serial port of the computer. View (b); / / View the second number b on the serial port of the computer. View(c); //View the third number c on the serial port of the computer. While(1) { } } /*---The end of the C language learning area. -----------------------------------------------*/ void View (unsigned long u32ViewData) { static unsigned char Su8ViewBuffer[43]; code unsigned char Cu8_0D_0A[]={0x0d,0x0a,0x00}; code unsigned char Cu8Start[]={"begin..."}; static unsigned char Su8FirstFlag =0; static unsigned int Su16FirstDelay; if(0==Su8FirstFlag) { Su8FirstFlag=1; for(Su16FirstDelay=0;Su16FirstDelay<10000;Su16FirstDelay++); SendString(Cu8Start); SendString(Cu8_0D_0A); SendString(Cu8_0D_0A); } to_BufferData (u32ViewData, Su8ViewBuffer, 1); SendString(Su8ViewBuffer); to_BufferData(u32ViewData,Su8ViewBuffer,2); SendString(Su8ViewBuffer); to_BufferData(u32ViewData,Su8ViewBuffer,3); SendString(Su8ViewBuffer); to_BufferData(u32ViewData,Su8ViewBuffer,4); SendString(Su8ViewBuffer); SendString(Cu8_0D_0A); } void to_BufferData(unsigned long u32Data,unsigned char *pu8Buffer,unsigned char u8Type) { code unsigned char Cu8Array1[]={0xB5,0xDA,0x4E,0xB8,0xF6,0xCA,0xFD, 0x00}; code unsigned char Cu8Array2[]="decimal:"; code unsigned cha r Cu8Array3[]="hexadecimal:"; code unsigned char Cu8Array4[]="binary:"; static unsigned char Su8SerialNumber=1; static unsigned int Su16BufferCnt; static unsigned int Su16TempCnt; static unsigned int Su16TempSet; static unsigned long Su32Temp1; static unsigned long Su32Temp2; static unsigned long Su32Temp3; static unsigned char Su8ViewFlag; if(1==u8Type) { for(Su16BufferCnt=0;Su16BufferCnt<7;Su16BufferCnt++) { pu8Buffer[Su16BufferCnt]=Cu8Array1[Su16BufferCnt]; } pu8Buffer [2]=Su8SerialNumber+'0'; pu8Buffer[Su16BufferCnt]=0x0d; pu8Buffer[Su16BufferCnt+1]=0x0a; pu8Buffer[Su16BufferCnt+2]=0; Su8SerialNumber++; return; } else if(2==u8Type) { for( Su16BufferCnt=0; Su16BufferCnt<7;Su16BufferCnt++) { pu8Buffer[Su16BufferCnt]=Cu8Array2[Su16BufferCnt]; } Su32Temp1=1000000000; Su32Temp2=10; Su16TempSet=10; } else if(3==u8Type) { for(Su16BufferCnt=0; Su16BufferCnt<9;Su16BufferCnt++) { pu8Buffer[Su16BufferCnt]=Cu8Array3[Su16BufferCnt]; } Su32Temp1=0x10000000; Su32Temp2=0x00000010; Su16TempSet=8; Else { for(Su16BufferCnt=0;Su16BufferCnt<7;Su16BufferCnt++) { pu8Buffer[Su16BufferCnt]=Cu8Array4[Su16BufferCnt]; } Su32Temp1=0x80000000; Su32Temp2=0x00000002; Su16TempSet=32; } Su8ViewFlag=0; for(Su16TempCnt=0;Su16TempCnt [11.2 Instructions for use of the template program. 】
Figure 11.2.1
Most beginners are learning the C language when they are learning the C language. The method is to install the VC platform software on the computer to practice the C language. This method only needs to call the printf statement in the code, and after compiling, you can see the variables called by the printf statement. Very convenient. This tutorial does not use this method. Since the C language of this tutorial is mainly for single-chip microcomputers, I have come up with another method. This method is to practice C language directly on the single-chip microcomputer, which will make the beginner experience more profound. This method is not very demanding on the hardware platform. As long as there is a 9-pin serial port on the 51 learning board, this serial port can be used to burn the program, or to observe a variable in the code, as long as it is in the code. Calling the View function can achieve the effect of the printf statement similar to the VC platform software. The View function can output the decimal, hexadecimal and binary of a variable to the serial port. You can see a variable in the serial assistant software on the computer. This information, the maximum value range of the variable that the View function can view is a 4-byte unsigned long variable. The decimal range is from 0 to 4294967295. You can also view the type variables of unsigned int and unsigned char (the hexadecimal and long of the data). , int, char and other knowledge points have not been touched yet, so it doesn't matter if you don't understand it. At present, as long as you have a general understanding, you don't need to understand it in depth, and the later chapters will introduce them in detail.) The View function is part of my entire template program, so to use this method you must first copy my entire template program. The scope of the beginner practice code is limited to the "C language learning area" in the template program. There is a main main function, there is an initialization area in the main main function. Beginners often practice C language in this initialization area. The maximum activity range of beginners cannot exceed the "start of C language learning area" to " The end of the C language learning area", the code of other parts outside this range is mainly used to implement the functions of data processing and serial port transmission. You don't need to read it for a while, you can copy it directly. such as:
/*---The beginning of the C language learning area. -----------------------------------------------*/
Void main() // main function
{
/ / ... initialization area, which is mainly used to learn the area of ​​C language for beginners.
While(1)
{
}
}
/*---The end of the C language learning area. -----------------------------------------------*/
In the above example, the beginner practice code can only be in the range from "the beginning of the C language learning area" to the "end of the C language learning area", and the code outside this range is directly copied and not changed. Let's analyze and analyze the source code of the main function in the following excerpt:
/*---The beginning of the C language learning area. -----------------------------------------------*/
Void main() // main function
{
Unsigned char a; //Define a variable a.
Unsigned int b; //Define a variable b.
Unsigned long c; //Define a variable c.
a=100; // Assign a value to variable a.
b=10000; // Assign a value to variable b.
c=1000000000; // Assign a value to the variable c.
View (a); / / View the first number a on the serial port of the computer.
View (b); / / View the second number b on the serial port of the computer.
View(c); //View the third number c on the serial port of the computer.
While(1)
{
}
}
/*---The end of the C language learning area. -----------------------------------------------*/
In the main function code of the above excerpt, for example, "a=100; // assign a value to variable a." This line of code, the so-called "assignment" is the statement "=", which appears to be equal to the number we usually use, actually The upper is not equal to the number, but the meaning of "give", copy the number on the right side of the "=" symbol to the variable on the left, such as "a=100;" means to copy the value of 100 to the variable a, After executing this instruction, a is equal to 100. The semicolon ";" here represents the end of a program instruction. The double slash "//" is a comment statement. The text or characters after the double slash "//" are used for comments. The compiler ignores the text after the double slash "//" line. Or the character, the compiler does not include the comment text or characters in the source code, that is, the text or characters in the line "//" do not occupy the memory of the microcontroller. Of course, "//" is limited to the current line of code. In addition to "//" is a comment statement, the above "/*" and "*/" are also comment statements, the same as "//", except that "/*" is the beginning of the comment, "*/ "The end of the comment, their scope is not limited to one line, but from the range of "/*" to "*/", so it can be used to comment on multiple lines of text or characters.
Then analyze the most important function in the above code, which is also the most important function of this section (a variable). For example, "View(a);" this line of code, View (a) is to send the decimal, hexadecimal and binary values ​​of the variable a to the serial port, we connect the learning board to the computer through the USB to serial cable. The information of the variable a called by the View function can be seen on the computer serial port assistant software.
[11.3 How to use the serial port assistant software on the computer to view the variables called by the View function? 】
In the previous chapter, I mentioned a PC software called “stc-isp-15xx-v6.85I†when I was programming the program. In addition to the program, the software also integrates the functions of the serial assistant software. Therefore, this section directly shares the USB to serial cable and "stc-isp-15xx-v6.85I" software when burning the program, no need to purchase a new USB to serial cable and download other serial assistant software, but how to Set up this "stc-isp-15xx-v6.85I" PC software, there are still some places that need special attention, now introduce this detailed step to everyone.
Step 1: Set the options for burning the software.
Follow the steps in the previous section to describe the programming procedure. Connect the 51 learning board and computer with the USB to serial cable, record the COM number, open the “stc-isp-15xx-v6.85I†software, select the MCU model, and select the corresponding Serial port number (COM number), set the lowest baud rate and the highest baud rate. The content of this part is the same as the configuration procedure when programming the program. The only thing that must be paid attention to is that the highest baud rate must be selected 9600! The lowest baud rate is recommended to choose 2400. Otherwise, after the program is burned, when the host computer integration software automatically switches to the serial port assistant software window, some Chinese characters displayed in the receiving area may be garbled.
---------------------------------- The dividing line between the steps ---------- ------------------------------
Figure 11.3.2
Step 2: Set the options for the serial assistant software.
First click on the upper right to select the "Serial Assistant" option to switch to the serial port assistant window, the receive buffer select "text mode", the serial port selects the matching COM number (common number with the burning software), the baud rate must select 9600, Tick ​​the “Automatically open serial port after programming is completed†option, and finally click the “Open Serial Port†button to switch to the text state of “Close Serial Portâ€, and the serial assistant software is set. The next step is to open the new HEX program file according to the flow of the programming program. After the program is burned, the host computer software will automatically switch to the serial port of the serial port assistant, and you can observe the variable sent by the View function from the MCU. Decimal, hexadecimal, binary information. The window of the receive buffer is relatively small. If you receive more information, just drag the slider on the right side of the window in the up and down direction to see all the information in turn. If you want the MCU to resend the data, you can resend the data once the 51 learning board is powered off. When the receiving information in the receiving area of ​​the serial port assistant has too much influence on the observation, you can click the button to clear the receiving area. Screen, then power off and restart to let it resend the data again. What is the data format observed in the computer's serial assistant software? For example, after compiling the complete template source code program in this chapter, you will see the contents of the three variables a, b, and c in the serial assistant software as follows:
Start...
First number
Decimal: 100
Hex: 64
Binary: 1100100
Second number
Decimal: 10000
Hex: 2710
Binary
Third number
Decimal
Hex: 3B9ACA00
Binary
To put it more, after the program is burned, when the software automatically switches to the window of the serial assistant software option, the serial port assistant window displays the information returned by the MCU. At this time, the first line of the text "Start..." will be lost or displayed. Not coming out, but the other key information behind is not affected. I guess it may be a small bug in a certain part of the serial assistant software itself. It doesn't matter to us. We don't need to go into the reason because it will not affect our use. At this point, if you let the MCU power off and restart, you can see the first line of the text "Start...".
[11.4 How to use the existing project editing to compile new source code? 】
There are a lot of chapters in the source code behind this tutorial. Is it necessary to rebuild a project for each chapter? Actually not. We can compile and edit the source code of all the chapters of this tutorial with just one project. The method is very simple, that is, open an existing project, use the shortcut key combination "Ctrl+A" to select all the C source code in the original project, then press "Backspace" to clear the original code, and then copy the relevant chapters of this tutorial. Paste the code into the C document of the project and recompile it to get the corresponding burned file in Hex format. When using this method, it is recommended that you do a backup of each program code. Every time a small project is completed, the source code should be stored in the computer hard disk in time. Each project in the computer hard disk corresponds to a project folder. Each project folder contains many source code files with different version numbers. The source code file name has a serial number to facilitate the identification of the latest version of the program. Every day before work, upload the latest version of the source code file to your own network disk for backup. In the Internet era, save the source code to your own network disk. It can be accessed from anywhere at any time, and there is no fear of permanent data loss even if it is damaged by a computer.
[11.5 Edit 5 common shortcut keys of the source code. 】
Introduce the commonly used shortcut keys, make good use of these 5 shortcut keys, will make you significantly improve the efficiency of editing the source code.
(1) Select all the contents of the whole article: the key combination Ctrl+A.
(2) Copy the selected content to the temporary clipboard: key combination Ctrl+C.
(3) Paste the contents of the temporary clipboard to the beginning of the cursor: key combination Ctrl+V.
(4) Move the selected line or lines to the right as a whole: One-touch Tab. It is useful to move a few spaces each time you press it.
(5) Move the selected line or lines to the left as a whole: the key combination Shift+Tab. It is useful to move a few spaces each time you press it.
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