Author: Liu Guangqiang, Chen Xi, Liu Qing, Chen Dan, Ma Xingru
This article is compatible with STC89C52 traditional development board and the exert of a piston to maximize resource allocation design core board, combined with Keil C compatible graphical programming language, and explain the hardware and software development of 51 single-chip microcomputer based on project development and teaching applications. Based on better propeling the application of single-chip technology teaching and project development.
0 Preface
Many of the specialty of single-chip teaching in many high-vocational colleges have students involving different levels of professional levels, in learning single-chip microcomputer and practical development applications, especially when the single-chip hardware structure and software programming are more difficult to get started. Based on many single-chip teaching and application research and apprentice teaching reform and exploration, from single-chip application and teaching status analysis, STC8H8K64U microcontroller introduction, STC8H8K64U compatible STC89C52 development board core system design and graphical programming and simulation and other five aspects, METG Teaching and Teaching Reform and Single Chip Microcomputer Lovers learn research.
1 Single-chip application and teaching mode and statement
As the development design and embedded foundation of smart electronics, the single-chip design includes: Guo Tianxiang's "new concept 51 single-chip microcomputer", related microcontroller development experience and sharing; a 51 microcomputer course as an example of Chuangke Project Teaching Application research in programming courses; Shaohua teacher is significant in the practice and comparison of project-oriented curriculum in the "MCU Programming and Training" course; Chen Yucheng's programming method in the programming method for beginners The method of programming dictionary can make single-chip beginners quickly master the programming of the microcontroller.
The programming mode of the single chip microcontroller is also a new month. As the traditional 51 single-chip C language programming skill is discussed, the programming characteristics and skills and modular programming design; Zhang Huilin teaches the modular programming method in detail in the programming modular design research of single-chip microcomputer; Limenshan Teacher's flowchart programming single-chip software system development, combining program code with intuitive graphics, with graphical programming changes to the requirements of programs syntax and syntax; Huang Rui's application in the two-programming language , Use assembly language and C language implementation, comparison teaching of selection and fusion; graphical single-chip programming project design based on Internet + technology's large case-based blowing exercise instrument, and mountain sheep belly based on innovative entrepreneurial teaching practice project The biological network application design is also invested from the aspects of project design and teaching practice. It can be seen that the microcontroller application and teaching resources have been very dazzling.
2 STC8H8K64U single-chip introduction
Hongjing Technology's "STC8H Series Single Chip Technology Reference Manual" shows that the STC8H series single-chip microcomputer can not require external crystal and external reset, is a target 8051 single-chip microcomputer with super anti-anti-interference, ultra-low price, high speed, low power consumption 8051 single-chip microcomputer, At the same operating frequency, the STC8H series monolithic machine is 12 times higher than the traditional 8051. The complete 111 instructions are performed in sequence, and the STC8H series microcontroller only needs 147 clocks, and the traditional 8051 requires 1 944 clocks. The STC8H series single-chip microcomputer is a single-chip microcomputer (1T) of STC production, is a new generation of wide voltage, high speed, high reliability, low power consumption, strong anti-static, strong anti-interference, super encryption, command code Completely compatible with traditional 8051.
3 STC8H8K64U compatible core system design of STC89C52 development board
3.1 STC8H8K64U Compatible STC89C52 Development Board Design Significance
According to the functionality and pin definition of STC8H8K64U and STC89C52, the STC8H8K64U core board is compatible with the traditional STC89C52 40P development board, which is both compatible with the STC89C52 teaching development board resources, and retains the STC8H8K64U 64-pin full-feature, so that the development of resources Using maximizes, it has a good meaning in teaching and application.
3.2 STC8H8K64U Compatible with the pin corresponding to the STC89C52 development board
In accordance with the functional characteristics and pins of STC8H8K64U and STC89C52, the pins and functions correspond to the principles of the STC8H8K64U 64-pin full-feature, such as Table 1.
3.3 STC8H8K64U Compatible STC89C52 core board design schematic (Figure 1)
3.4 STC8H8K64U compatible STC89C52 core board design instructions
According to the STC8H8K64U compatible STC89C52 traditional 40P base development board and the principle of the STC8H8K64U 64-pin full-feature, the related devices and pins are arranged, as shown in Figure 2.
4 STC8H8K64U core board graphical programming and simulation
4.1 STC8H8K64U core board graphical programming software
Currently, hardware and software is more than classic "Days 51" series development boards and graphical programming software with two programming environments with online programming and offline programming. Offline programming can be graphically programmed directly, and generate SDCC-based character C files, or directly programmed directly in the character programming window; program results can directly connect to the development board to run online by "Day Ask" downloader, implement real object simulation The effect can also be directly compiled to generate the main.c file. Online programming environments can also directly export Keil C engineering documents, which is very convenient. "Day" graphical programming software can be downloaded in its official website, currently Block0.1.6, installation.
4.2 STC8H8K64U core board graphical programming method
There are a lot of tutorials and reference information about the graphic programming, and after opening the day, after opening the BLOCK software, there is a corresponding operational ribbon and menu buttons, as shown in Figure 3. Click on the folder icon menu button in the upper left corner, "New Project", "Open Project", "Save", "Save", Project Center, Submit Jobs, can make new, open projects, Save and other related operations.
The left side function modules and logic control graphical instructions include single-chip internal modules, such as system configuration, GPIO module, PWM module, ADC module, timer module, serial module, external interrupt setting, all interrupt settings, read and write registers. Logic and control modules include: control, math, logic, text and arrays, variables, functions. The text module includes: a display module (LED water lamp, HC595 string and off-shift buffer, digital tube, dot matrix LED, RGB water lamp, OLED screen, LCD1602 screen, LCD12864, TFT color screen, color screen touch), sensor module, infrared , I2C, SPI, extension and other modules. The rich functional module and library function bring a lot of convenience to project development applications, and introduce teaching applications more beneficial to beginners.
Graphical programming and character programming are located on the two main windows left and right in the interface main ribbon, to meet the maximization of the programming window, and the two window sizes can be dragged to change the corresponding window size with the triangular button under its cross-bounds to meet the graphical programming. Or the needs of characters programming courses.
The unconnected menu indicates that there is no connection to the corresponding development board. If the development board is connected to the computer USB port, the connected device will be displayed, and the program can be programmed, and the program is used for online hardware simulation. Or compilation to generate main.c files, KEILC environment is used. Among them, running procedures for online hardware simulation breaks through traditional Keil C software simulation or through STC-ISP simulation, more direct programming and view results at any time, very convenient. The "More" menu in the upper right corner of the software provides programming manuals, chip manuals, video learning, developer forum, purchase, installation driver and other functional modules, so that learning programming is more convenient, and the programming manual provides the basics of beginners using software. Method Introduction, video learning uses operational video through programming of each function program, more intuitive and image display methods.
4.3 STC8H8K64U core board graphical programming skills
Although the software has made a single-chip programming very simple image, it may be a guidance and instructions for beginners.
1) "Day" graphical programming based on modular design, the corresponding function module has formed a function function to encapsulate, and the programmer only needs to be called according to functional requirements, as shown in Figure 4.
The entire program follows a main program entry:
Void main (void)
{
setup ();
While (1) {
Loop ();
}
}
Perform initialization and repeated execution of functional subroutines in the main program:
Void setup ()
{
TWEN_BOARD_INIT (); // Today 51 Initialization
}
void loop ()
{
}
The STC8 header file and system clock initialization also gives the system framework for default:
#include "stc8hx.h" uint32 sys_clk = 24000000; // Setting PWM, Timer, Serial port, EEPROM frequency parameters
#include "lib / twen_board.h"
2) It can be seen from the "Day" Block graphical programming framework that all initialization includes port definition, variable, and function definition, timer and interrupt, etc. Initialization in the "Initialization" frame module, and the main function procedures are all put In the "Repeat" frame module. It should be noted that the initialization work is very important. Before the function module is operated, you must first look at there is no corresponding initialization building block command. If there must be placed in the initialization framework. Place the function program in the "Repeated" framework, clearly put all the functional programs directly in this frame, not only readability, it is not convenient to debug and transplant, it is best to decompose each functional program to a subroutine. Then call in the "Repeated" framework, according to the complexity of the program function, the multi-stage subroutine (function) module can be performed.
3) Although the functional program is to be executed in the "Repeated" framework, the programs executed in this framework are in accordance with the order sequence, and many times some functional programs are regularly executed, and the timer mode can be used Perform, so in the timer can be performed in accordance with the design time timing, and it will not occupy the resources of the "Repeat" framework.
4) For graphical programming, many beginners either have difficult to master programming processes and ideas, or I don't know how to call appropriate instructions, or the program logic is unreasonable, resulting in failure or crash. With the way of flow chart and modular programming, the functionality to be implemented will be combed, and then the functional program is allocated, and the functionality implemented according to the required function corresponds to the single-chip hardware interface and related circuit components. The core board for this project is also to be compatible with the traditional STC89C52 development board. It can directly insert it directly on the corresponding 40P base, using existing development board hardware resources such as LED lights, buttons, digital tubes or some sensors and relay lamps, or The components are connected to the core board as required by DuPre lines separately as needed.
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