CN102194351A - 8051-or-AVR-based multi-core singlechip teaching experimental platform - Google Patents

Abstract

The invention discloses an 8051 or AVR-based multi-core microcontroller teaching experiment platform, which belongs to the field of embedded computers. The hardware of the platform includes two circuit boards, the main board and the AVR adapter board. The 8051 single-chip microcomputer adopts AT89S52, and the AVR single-chip microcomputer adopts ATMEGA32. AT89S52 can be directly plugged into the motherboard to work, and the platform works in 8051 mode at this time; ATMEGA32 can be inserted into the motherboard through the AVR adapter board to work, and the adapter board completes the conversion from the ATMEGA32 pin package to the AT89S52 pin package, and the platform works at this time In AVR mode. The motherboard is composed of power supply, basic function part and interface communication part. The platform software system is divided into two layers. The driver layer completes the encapsulation of two kinds of single-chip hardware resources. The application layer is a comprehensive demonstration program including 14 experiments. It runs under the support of the driver layer and has hardware-independent characteristics.

Description

A teaching experiment platform of multi-core microcontroller based on 8051 or AVR

technical field

The invention belongs to the field of embedded computers and relates to an 8051/AVR-based multi-core microcontroller teaching experiment platform.

Background technique

In the current single-chip microcomputer course teaching in colleges and universities, there are problems such as repeated purchase of experimental equipment, and the disconnection between equipment functions and social needs. On the one hand, single-chip microcomputers have a wide range of applications, and different types of single-chip microcomputers are suitable for different occasions. There are large differences between these single-chip microcomputers. In order to enable students to adapt to different needs of society, colleges and universities often need to purchase multiple types of single-chip microcomputer equipment. There are overlapping functions, which will inevitably cause a certain degree of waste. On the other hand, with the rapid development of embedded computer technology, various single-chip microcomputers and peripheral models are constantly being introduced, how to determine a set of experimental equipment that is most suitable for students to use among many choices, in terms of complexity, typicality, convenience, and reliability And how to achieve the best balance between equipment costs is a problem that educators need to study carefully. After a lot of research, it is found that 8051 series single-chip microcomputers and AVR series single-chip microcomputers are the most widely used in China. If a teaching experiment platform can be designed to support these two kinds of single-chip microcomputers at the same time on the basis of covering various commonly used typical equipment, you can achieve One set of equipment undertakes the purpose of two experimental courses, effectively reducing equipment costs and saving teaching resources.

Contents of the invention

The technical problem to be solved by the present invention is to design a circuit board, an AVR adapter board, and a set of software systems based on two single-chip microcomputers. The system is suitable for teaching and scientific research occasions related to single-chip microcomputer.

Technical scheme of the present invention:

Based on 8051/AVR multi-core single-chip teaching experiment platform, the hardware includes two circuit boards, the main board and the AVR adapter board, the 8051 series single-chip microcomputer adopts AT89S52, and the AVR series single-chip microcomputer adopts ATMEGA32. The software includes driver layer software and application layer software based on AT89S52 and ATMEGA32 MCUs.

The multi-core MCU teaching experiment platform based on 8051/AVR has two working modes, called 8051 mode and AVR mode:

1.8051 mode: Insert the AT89S52 MCU into the MCU socket of the motherboard, and the

Chip microcomputer power supply, the single chip microcomputer controls all the hardware modules of the motherboard through the socket; in the integrated development of PC

Under environmental control, the program can be debugged and downloaded to the multi-core microcontroller teaching experiment platform.

2. AVR mode: The AVR adapter board is designed with a 40-pin single-chip socket, and the ATMEGA32 single-chip

Insert the computer into it, and then insert the AVR adapter board into the socket of the motherboard single-chip microcomputer, and the motherboard will send

Single-chip microcomputer power supply, the single-chip microcomputer controls all hardware modules of the main board through the adapter board; in the integration of PC

Under the control of the development environment, the program can be debugged and downloaded to the multi-core microcontroller teaching experiment platform.

The motherboard is composed of power supply, basic function part and interface communication part. The power supply part supports two ways of USB power supply and external DC power supply. The LM7805 three-terminal voltage regulator and LM1117-3.3 integrated voltage regulator chip are used to provide 5V and 3.3V power supplies for the experimental platform, and include a button reset circuit. The basic function part includes reference source module, keyboard input module, voice input module, voice output module, display module and buzzer module. The reference source is provided by the LM336 chip, which outputs a stable 5V voltage signal; the keyboard input module includes a 2*3 keypad; the voice input module uses a professional voice chip ISD4004 to record and play the voice; the voice output module amplifies the voice signal through the LM386 chip and sends it to the To the speaker; the display module includes light-emitting diodes, common cathode 4-digit 8-segment digital tubes, 8*8 LED dot matrix and OCM12864 liquid crystal display; the buzzer adopts HYDZ type and is driven by NPN type transistor. The interface communication part includes single chip socket, ISP program download interface, DS18B20 temperature sensor interface, MAX232 serial interface, infrared communication interface, relay output interface and stepper motor interface.

和VPP引脚，将ATMEGA32的31号引脚GND接地，AT89S52的30号引脚悬空。The function of the AVR adapter board is to complete the conversion from ATMEGA32 pin package to AT89S52 pin package. Both AT89S52 and ATMEGA32 are packaged in DIP40, but the pin order of the two is different. The mainboard circuit of the experimental platform is designed according to the pin definition of the AT89S52 single-chip microcomputer. In order to insert the ATMEGA32 single-chip microcomputer into the mainboard single-chip microcomputer socket, the pin sequence of the ATMEGA32 single-chip microcomputer must be adjusted through the AVR adapter board. The adapter board maps the 32 I/O ports of the ATMEGA32 MCU - P0.0 to P3.7 to the P0.0 to P3.7 of the AT89S52, and maps the two crystal interfaces XTAL1 and XTAL2 of the ATMEGA32 to the XTAL1 and XTAL2 of the AT89S52. XTAL2, map VCC, GND and RESET pins of ATMEGA32 to VCC, GND and RESET of AT89S52, map AVCC and AREF pins of ATMEGA32 to AT89S52

and VPP pin, ground the 31st pin GND of ATMEGA32, and the 30th pin of AT89S52 dangling.

The software system includes two parts: the driver layer software and the application layer software. The driver layer completes the packaging of the hardware, making the application layer hardware-independent. Because the experimental platform supports 8051 and AVR two single-chip microcomputers, the driver layer software includes two corresponding versions: 8051-based driver layer software and AVR-based driver layer software. The driver layer software includes drivers for all hardware modules and interfaces, exists in the form of a function library, and provides a unified call interface to the upper layer software. The application layer software calls the driver layer software interface to complete the control of the hardware and implement a comprehensive demonstration program. When the system is powered on, a top-level function demonstration menu will be displayed on the LCD. The user can select the module function to be demonstrated by pressing the button, and the demonstration is completed. After that, you can return to the top menu.

The beneficial effect of the present invention is that different single-chip microcomputers can be used to control the hardware resources of the main board. In the experimental teaching, the same set of equipment is used, and different single-chip microcomputers are replaced according to different course requirements, so that multiple experimental courses share a set of equipment, effectively reducing the equipment cost. Acquisition fees and teacher training fees.

Description of drawings

Fig. 1 is a system structure diagram of the present invention.

Fig. 2 is a structural block diagram of the motherboard of the present invention.

Fig. 3 is a schematic diagram of the AVR adapter board of the present invention.

Among them: 1ATMEGA32 single-chip microcomputer pin; 2AT89S52 single-chip microcomputer; 3-pin circuit connection.

Fig. 4 is a software structural block diagram of the present invention.

Detailed ways

The specific embodiments of the present invention will be described in detail below in combination with the summary of the invention and the accompanying drawings.

As shown in Figure 1, the 8051/AVR-based multi-core MCU teaching experiment platform includes three components: main board, adapter board, and software system.

(1) Motherboard

The motherboard hardware resources of the 8051/AVR-based multi-core MCU teaching experiment platform can be divided into three parts according to the functions: power supply, basic function part and interface communication part, as shown in Figure 2.

The power supply part is provided with two optional power input methods, which are USB power supply and external DC power supply, which are selected by a single-pole double-throw switch. In the USB power supply mode, the 5V DC from the USB interface of the PC is directly introduced into the experimental platform; in the external DC power supply mode, a 9V DC voltage is introduced into the experimental platform, and the voltage is stabilized to 5V by using the LM7805 three-terminal voltage regulator. The experimental platform also needs a 3.3V power supply. In the aforementioned two power supply modes, use the LM1117-3.3 voltage regulator chip to stabilize the 5V voltage at 3.3V. The power supply terminal is connected with a self-recovery fuse with a fusing current of 500mA, which can protect the hardware modules on the circuit board from being damaged by instantaneous high current. At the same time, the experimental platform is designed with power lead-out terminals, which can lead out the 5V power supply and 3.3V power supply of the experimental platform for use by other equipment. The reset pin levels of AT89S52 and ATMEGA32 microcontrollers are just opposite. The experimental platform has designed a reset button for each of these two microcontrollers, and a three-position jumper can be used to choose to reset AT89S52 or reset ATMAGE32.

The basic function modules include a reference source module, a keyboard input module, a voice input module, a voice output module, a display module and a buzzer module. The reference source circuit is realized by LM336 chip with capacitor and resistor, which provides 5V reference voltage for ATMEGA32 microcontroller. The experimental platform is designed with a small keyboard with 2*3 buttons. The row and column scanning method is used to detect the buttons, and the software delay of 20 milliseconds is used to deal with the button jitter. The voice input module adopts the ISD4004 voice chip, which receives the voice signal from the microphone and stores it in the on-chip Flash memory, and sends it to the voice output module synchronously. The voice output module receives the audio signal provided by the voice input module, and outputs it to the positive input terminal of the audio amplifier chip LM386, which can be adjusted and amplified by 20-200 times through a 10K sliding resistor, and finally outputs the voice signal through the speaker interface. The display output module includes 4 light-emitting diodes, 4-digit 8-segment digital tube with common cathode, 8*8 LED dot matrix and OCM12864 liquid crystal display. Among them, the colors of the four light-emitting diodes are red, yellow, blue, and white; the LED dot matrix is controlled by two 74HC595 latches; the OCM12864 liquid crystal display is controlled by a 74HC595 latch. The digital tube and the 12864 LCD screen are controlled by 7 identical single-chip I/O ports. In order to avoid data conflicts, when the digital tube is working, the LCD screen cannot be plugged into the 12864 interface at the same time; when testing the LCD screen, just unplug the digital tube jumper cap switch. The buzzer adopts the HYDZ model and is controlled by an NPN transistor. The base of the transistor is connected to the I/O port of the microcontroller through a jumper.

The interface communication part includes single-chip microcomputer socket, ISP program download interface, temperature sensor interface, serial interface, infrared communication interface, relay output interface and stepping motor interface. The experimental platform is equipped with a 40-pin microcontroller socket, which can be inserted into an AT89S52 microcontroller or an AVR adapter board. The ISP program download interface conforms to the ATMEL standard, and the program can be downloaded online by connecting the programmer to the USB interface of the PC, and can simultaneously support AT89S52 and ATMEGA32 single-chip microcomputers. The temperature sensor interface can be installed with a DS18B20 temperature measurement chip, and the temperature measurement, conversion and transmission can be completed through a one-line bus. The bus is connected with a 4.7KΩ pull-up resistor. The serial interface adopts RS232C standard nine-pin interface, and the MAX3232 control chip realizes data sending and receiving and level conversion. The infrared communication interface can be installed with an integrated infrared probe to complete experiments related to infrared control. The relay output interface includes a SRS-05VDC-SL relay with a withstand voltage of 30V and can output switching values. The stepper motor interface uses MC1413 Darlington tube as the driver chip, and the 7 input and output ports are all connected by pin headers. When working, they can be flexibly switched with Dupont wires, which can control a variety of stepper motors, and can also control DC motors ; The motor power supply part is connected with a high-capacity tantalum capacitor as a motor filter to reduce signal interference to the main board.

The corresponding relationship between each module on the motherboard and the pins of the microcontroller is shown in the following table:

(2) AVR adapter board

和

引脚，另外，ATMEGA32单片机的31号引脚GND接地，AT89S52的30号引脚

悬空。The AVR adapter board of the multi-core MCU teaching experiment platform based on 8051/AVR is shown in Figure 3, which is responsible for mapping the pins of the ATMEGA32 MCU to the pin positions of the AT89S52 MCU. These two single-chip microcomputers are both in DIP40 package, and only need to connect the pins with the same function through the circuit to control the resources of the motherboard. The specific connection method is that the AVR adapter board maps the 32 I/O ports P0.0 to P3.7 of the ATMEGA32 microcontroller to the corresponding I/O ports of the AT89S52, and maps the two crystal oscillator interfaces XTAL1 and 2 of the former to the latter The corresponding interface of the former, the VCC, GND and RESET pins of the former are mapped to the corresponding pins of the latter, and the AVCC and AREF pins of the former are mapped to the latter’s

and

In addition, pin 31 of ATMEGA32 MCU is GND grounded, and pin 30 of AT89S52

dangling.

The details of the pin correspondence of the adapter board are shown in the table below:

(3) Software system

Based on the 8051/AVR multi-core microcontroller teaching experiment platform, the complete control of the resources of the experiment platform is realized through the software system. The software system is divided into two levels, the bottom driver layer and the upper application layer. The driver layer includes a set of driver function libraries based on AT89S52 and a set of driver function libraries based on ATMAGE32. The driver layer directly interacts with the hardware, and provides a unified programming interface for the upper-layer software by encapsulating the functions of the underlying hardware; the application layer includes a comprehensive demonstration program, which uses the programming interface provided by the driver layer to control the hardware resources of the experimental platform, and has hardware-independent characteristics. When using 8051 microcontroller, the driver layer is based on 8051 design; when using AVR microcontroller, the driver layer is based on AVR design. The two types of driver layers provide a unified interface function call form to the upper layer, so the application layer of the system is consistent for the two types of single-chip microcomputers. The block diagram of the software system is shown in Figure 4.

The main modules contained in the driver layer correspond to the motherboard hardware one by one. The modules exist in the form of a function library, specifically including 12: buzzer driver, button driver, voice input driver, voice output driver, digital tube driver, dot matrix driver, LCD Display driver, infrared interface driver, serial interface driver, stepper motor driver, temperature sensor driver, relay driver.

The application layer includes a comprehensive demonstration program, which includes multiple functions, and each function is an experimental demonstration program to show the user the operation mode of the corresponding hardware part. When the system is powered on, the LCD displays a top-level function demonstration menu, and the user selects the module function to be demonstrated by pressing the buttons. After the demonstration is completed, the software process automatically returns to the top-level menu.

The function items contained in the top-level menu are shown in the table below:

Claims (1)

1. one kind based on 8051 or the multinuclear heart single chip computer teaching experiment porch of AVR, it is characterized in that: comprise two circuit boards of mainboard and AVR card extender,

Mainboard partly is made up of power supply, basic function part and interface communication; Power unit is supported USB power supply and external direct current supply dual mode, adopts LM7805 three terminal regulator and the integrated voltage stabilizing chip of LM1117-3.3 to provide 5V and 3.3V power supply for experiment porch, and supports the button reset function; Basic function partly comprises reference source module, keyboard load module, voice input module, voice output module, display module and hummer module; Interface communication partly comprises single-chip microcomputer socket, ISP program download interface, DS18B20 temperature sensor interface, MAX232 serial line interface, infrared communication interface, relay output interface and stepper motor interface;

8051 single-chip microcomputers adopt AT89S52, and the AVR single-chip microcomputer adopts ATMEGA32, and experiment porch may operate under two kinds of mode of operations:

8051 patterns: with the single-chip microcomputer socket of AT89S52 single-chip microcomputer insertion mainboard, all hardware module of Single-chip Controlling mainboard; Under the control of the Integrated Development Environment of PC, can debug, experiment porch downloads;

The AVR pattern: the ATMEGA32 single-chip microcomputer is inserted the AVR card extender, the AVR card extender is inserted mainboard single-chip microcomputer socket again, single-chip microcomputer is by all hardware module of card extender control main board; Under the control of the Integrated Development Environment of PC, can debug, experiment porch downloads; The function of AVR card extender is the conversion of finishing from ATMEGA32 pin package form to AT89S52 pin package form; The motherboard circuit of experiment porch designs according to the pinout of AT89S52 single-chip microcomputer, adjusts the pin order of ATMEGA32 single-chip microcomputer by the AVR card extender, makes whole hardware resources that ATMEGA32 single-chip microcomputer pin can control main board.

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