Shulou(Shulou.com)06/01 Report--

After working for a long time and doing so many preparatory tasks, we finally have to write our program code. If you have learned the C language, you should easily follow my programming. If you have not learned the C language, it does not matter, you first follow my copy, I will write out the explanation of the C language grammar in an appropriate position. If you copy it a few times and then look at the explanation, it should be very clear. You must be careful when you copy, especially the punctuation mark Fu Cheng to make a mistake.

The first single-chip microcomputer program:

# include / / including the special function memory definition header file sbit LED = P0 ^ 0; / / bit address declaration, note: sbit must be lowercase and P uppercase! Void main () {/ / any C program must have one and only one main function LED = 0; / / semicolon indicates the completion of a statement}

Let's analyze it from the perspective of program syntax:

Main is the name of the main function, and every C program must have one and only one main function.

Void is the value type of the function. There is no previous value in this procedure. It is represented by void.

In this case, {} is the mark of the beginning and end of the function, which is omitted.

Each C sentence ends with.

From a logical point of view, the program can be written in this way, but there is an achievement in the practice of using single-chip microcomputer. For example, our program space can contain 100 lines of code, but our practical program uses only 50 lines of code. when we run 50 lines and then run continuously, the 51st line of the program is not the program we want to run, but uncertain unknown content. once implemented, the program will stumble and be able to cause the single-chip microcomputer to actively reset, so we usually participate in a dead cycle in the program. Let the program stay in this form of our desire, do not run randomly, there are two ways to write it for reference:

Reference procedure 1:

# include sbit LED = P0 ^ 0; void main () {while (1) {LED = 0;}}

Reference procedure 2:

# include sbit LED = P0 ^ 0; void main () {LED = 0; while (1);}

The function of program one is that the program repeats LED = 0 for a limited number of times from time to time; this statement, while the function of program two is to perform once, and then the program stays and waits directly, and the absolute program one is more concise. Needle about figure 2-6, our program can light the small lights, but this program does not light the small lights on our board, why?

Here everyone is about to cultivate an understanding, we do single-chip microcomputer programming, in practice is regarded as the hardware underlying driver development, the development of this program, is inseparable from the circuit diagram, must be based on our circuit diagram to stop programming. If we design the circuit diagram of the circuit board is the same as figure 2-6, the program can successfully light the small lamp, but if it is not the same, it can not be lit.

There is also a 74HC138 on our pioneer board as the main switch for 8 LED lights, while P0.0 is just an exit switch. It seems that there is always a power switch in our home, and then each light has a special switch, our program only turns on the switch of the light, but does not turn on the main switch, so the program needs to add this local code.

As there are more to be introduced in this class, we will introduce the truth of 74HC138 and why we need to add rated code. In this class, we will add this part of the code directly, and everyone knows that there is such a thing.

# include / / including the special function memory definition header file sbit LED = P0 ^ 0; / / bit address declaration, note: sbit must be lowercase and P uppercase! Sbit ADDR0 = P1 ^ 0; sbit ADDR1 = P1 ^ 1; sbit ADDR2 = P1 ^ 2; sbit ADDR3 = P1 ^ 3; sbit ENLED = P1 ^ 4; void main () {ENLED = 0; ADDR3 = 1; ADDR2 = 1; ADDR1 = 1; ADDR0 = 0; LED = 0; / / turn on the small lamp while (1); / / the program stops here}

Write so many cumbersome sentences, at first everyone can think that it is very troublesome, why some books program is very complex can light a small lamp, we are so troublesome here. Everyone should understand that although we make this study board, although we only provide everyone with complex learning and application, we also have to design according to the pioneering form of practical products, so there are many elements of comprehensive thinking. everyone will be clear about its design value after learning, and everyone here just needs to follow us.

When the program is finished, we need to stop compiling our program and generate the files we need that can be downloaded to the single-chip microcomputer. Before compiling, we need to check an option, Project-- > Options for Target Target1..., or directly click the shortcut icon in the red box in figure 2-17:

Figure 2-17 Project options icon

In the pop-up dialog box, click the Output option page, check the "Create HEX File" check box, and then click OK, as shown in figure 2-18.

Figure 2-18 create HEX file

For the future, click "Project-- > rebuild all target files", or click the shortcut icon in the red box in figure 2-19 to stop compiling the program.

Figure 2-19 compiler

After the compilation is completed, the Output window below our Keil will present a reminder of the response, everyone pay attention to figure 2-20, this window informs us of the situation after compilation is completed, data=9.0, refers to our program using 9 bytes of external 256byte RAM capital, code=29 means the use of 8K code Flash capital of 29 bytes.

When reminding "0 Error (s), 0 warning (s)" to show that there is nothing wrong with our program and warning, there will be "creating hex file from" LED "..., which means that a HEX file is generated from the project in the future, and it is this HEX file that we want to download to the single-chip microcomputer. If there is something wrong and warning that Error and warning are not 0, then we have to stop reflecting on the program, find out the results, deal with it, and then stop compiling HEX.

Figure 2-20 compilation input information

At this point, the program is compiled, and the following is about to download the compiled program file to the single-chip microcomputer.

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