CN101727099A - Identification and information exchange platform based on I2C structural model and communication protocol unit - Google Patents

Abstract

The invention discloses ^{an identity recognition and information interaction platform and a communication protocol unit based on an I 2 C} structure model, including several PIC single-chip microcomputers. Under the premise of , a data bus SDA and a timing bus SCL are interconnected through a data bus SDA and a timing bus SCL connected with pull-up resistors to form a network bus environment. The invention adopts a layered network protocol unit, can identify the site address and identity of the single-chip microcomputer under the simulated timing state, realizes effective data transmission, and the communication mode is safe and reliable, laying a technical foundation for realizing the networked management and data exchange of the single-chip microcomputer.

Description

Identity recognition and information interaction platform and communication protocol unit based on I2C structure model

technical field

The present invention relates to an identity recognition (referred to as ID, which is the abbreviation of Identity) and an information interaction platform, in particular to an identity recognition and information interaction platform based on an I ² C (Inter Integrated Circuit Bus, inter-chip integrated circuit transmission bus) structural model and communication protocol unit.

technical background

The serial extended communication interface is a platform and an important channel for data exchange between PIC (Periphery Interface Chip, peripheral interface chip) single-chip microcomputer and peripheral devices or other computers. Generally, single-chip microcomputers are equipped with multiple serial communication modules, among which the I ² C communication mode is more representative. The I ² C bus is a synchronous serial transmission bus between chips, and its working performance is relatively stable. It is currently widely used as the data transmission bus inside the system. The I ² C bus structure is very simple, relying only on two signal lines: a synchronous serial data line SDA (Serial Data, serial data line) and a synchronous serial timing signal line SCL (Serial Clock, serial timing signal line). The I ² C data transmission method is to use a data line SDA shared by the master and the slave device in time-sharing, which can include byte data information, address identification code and response handshake signal from both parties; the rate of I ² C data transmission depends on the clock pulse signal SCL frequency.

The I ² C structure bus is generally used for point-to-point data transmission between computers, single-chip microcomputers or other control modules. The communication protocol of point address identification and data information exchange is the key problem solved by the present invention.

Contents of the invention

The purpose of the present invention is to provide an identity recognition and information interaction platform and a communication protocol unit based on the I ² C structure model to build a single-chip network system environment, which can identify the site address and identity of the single-chip computer, realize effective data transmission, and the communication method is safe and reliable .

One of the present inventions: an identity recognition and information interaction platform based on the I ² C structure model, characterized in that it consists of several PIC single-chip microcomputers interconnected by the I ² C structure model and a keyboard connected to each PIC single-chip And the human-computer interaction module of the display constitutes a network architecture, in which: several PIC single-chip microcomputers are used for mutual identification and information interaction; the human-computer interaction module is used for data input and output.

In the above-mentioned I ² C structure model identity identification and information interaction platform, the interface pin RC0 of each PIC microcontroller is connected to the pull-up resistor and connected to the SDA of the data bus in the I ² C structure model, and each PIC After the single-chip interface pin RC1 is connected with a pull-up resistor, the corresponding interconnection constitutes the timing bus SCL in the I ² C structure model.

In the above-mentioned I ² C structure model identity recognition and information interaction platform, the keyboard of the human-computer interaction module is a 4*4 matrix keyboard; the display is a 3-digit digital dynamic display.

The second aspect of the present invention is a communication protocol unit for the above-mentioned identity recognition and information interaction platform based on the I ² C structure model, including a three-layer networked communication protocol.

The first-layer protocol includes the frame header subroutine, the frame tail subroutine, and the subroutine for sending and receiving a byte of data. It is hardware-oriented and undertakes the function of operating the bus. It belongs to the lowest physical transmission protocol or agreement;

The second-layer protocol also introduces the concept of data frame (packet), which includes three parts of data content in a frame of information: receiver ID identification code, sender ID identification code and data content to be sent. In addition, the data frame information shields the application layer from a large number of hardware processing operations at the bottom layer, so that the programming design of the application layer protocol is greatly simplified, and it is also convenient for online debugging or modification of the program;

The third-layer protocol is also included in the keyboard scanning module, which realizes switching of working states, data collection (setting) and display, and is an interactive protocol oriented to the application layer.

Due to the adoption of the above-mentioned technical solution, the present invention proposes a complete set of single-chip network protocol unit, which realizes effective data transmission and identification under the state of I ² C analog timing, and easily realizes controllable and directional data transmission between PIC single-chip systems Platform, thus laying a technical foundation for the realization of single-chip network management and data exchange.

Description of drawings

Fig. 1 is a schematic diagram of the principle of an identity recognition and information interaction platform of the present invention;

Fig. 2 is a schematic diagram of the communication mode of the identification and information interaction platform of the second invention.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing.

Please refer to Fig. 1, which shows an identity recognition and information interaction platform based on an I ² C structural model of the present invention. The networked identity recognition and information interaction platform is based on an I ² C structural model, which includes several The PIC single-chip microcomputer 21 without fixed master and slave roles constitutes the single-chip microcomputer and the human-computer interaction module 2, which includes a 4×4 matrix keyboard 23 for data and function input and an 8-segment digital display 22; A data bus SDA of the pull-up resistor 11 is correspondingly interconnected and a timing bus SCL is correspondingly interconnected, thereby constituting a standard I ² C structure model, such as module 1 .

In this embodiment, there are three PIC single-chip microcomputers, wherein RC0 and RC1 are respectively defined as a data bus SDA and a timing bus SCL for I ² C structure model communication, each of which is connected with a 4.7K ohm pull-up resistor, and the data The bus SDA and the timing bus SCL correspond to interconnection respectively, and the model of the PIC microcontroller is PIC16F877.

Please refer to Fig. 2, which shows a schematic diagram of an identity recognition and information interaction platform based on the I ² C structure model of the present invention, which is the data or information exchange between any single-chip microcomputer and other single-chip microcomputers in the network system aisle. The single-chip microcomputer interconnected based on the I ² C structure model, through the function definition and setting of the data bus SDA, becomes its role that can be exchanged at any time. It can be used as the active sender 3 and the slave receiver 4. The direction of information flow is determined. The control unit built by the single chip microcomputer, the network protocol established based on the I ² C structure model can realize the network protocol frame structure, which is mainly designed as a three-layer protocol content according to the data information exchange function, and describes any data in the network environment. The protocol relationship between the sending subject and the data receiving object. The implemented functions are described as follows:

Among them, the first layer is the physical transmission protocol layer, which belongs to the lowest protocol or agreement. It is mainly composed of the sending data module 33 in the sending end module 3 and the receiving data module 43 in the receiving end module 4. It is an information exchange between the subject and the object. The protocol channel of the hardware.

The second layer is an intermediate layer protocol, which introduces the concept of a data frame (packet) at the sending end 3 and the receiving end 4, and uses three parts of data content (receiver ID identification code, sender ID identity) included in the information of a frame identification code and data to be sent), the data is integrated through the data integration module 32, and then the data is decomposed in the data splitting module 42.

The third layer is the application layer protocol, which is a user-level design. On the basis of satisfying the system interaction protocol, it can be expanded, processed and set according to the personalized human-computer interaction interface (including keyboard and display), and the original data collection can be completed specifically. (sending end collecting data module 31) and subsequent data processing (receiving end processing received data module 41).

The networked communication protocol unit of the I ² C structure model identity recognition and information interaction platform is the rule for data exchange between single-chip computers, which can realize the conversion between system working states (listening/preparation/send), client and A series of operations such as changing the client identification code and refreshing the sent data can make the single-chip microcomputer intelligently enter the receiving, sending or waiting link.

The specific implementation process and completion can be as follows:

First of all, the occupation method of the bus control right must be determined. Any system can pull the data bus SDA and timing bus (high level in normal mode) to low level and keep it for a period of time (generally 30μs) through the frame header subroutine. Enough to make the receiver (other single-chip microcomputer systems except this system) can detect that the bus is occupied, so these systems all start to transfer to the stage of receiving data. During the receiving process, the receiver is always in a passive state to receive data bit by bit in an orderly manner, and the receiver will actively stop receiving until the content of a complete frame of data is received.

Secondly, each recipient will independently enter the ID identification verification and comparison, and only when it is consistent with its own ID identity code will it identify the sender's ID identity code and process the received data information. At the same time, a confirmation signal mechanism similar to the I ² C communication protocol is adopted. The receiver will temporarily occupy the bus control right and send back an ID identification code with the receiver, indicating that the relevant data has been received. The sender releases the bus immediately after executing the frame tail subroutine, and waits for the receiver's return confirmation signal;

Finally, if the confirmation signal is not received within a certain period of time (generally 50μs), the sender will re-occupy the bus and resend the original frame of data; and if the confirmation message is received, it will quickly hand over the control of the bus. Consciously switch to the monitoring state.

In this embodiment, only two decimal numbers are used to represent the identification code of the sender or receiver, but theoretically the length of the identification code can be infinitely expanded, that is, the number of terminal nodes of the single-chip microcomputer system in the network can be infinitely many indivual. The number of digits of the system digital display determines how many independent nodes with identification codes can exist in the network system, and the content of the transmitted data is also limited by the number of decimal digits expressed, but it can be expanded according to the usage.

The present invention has been described in detail above with reference to the embodiments of the accompanying drawings, and those skilled in the art can make various changes to the present invention according to the above description. Therefore, some details in the embodiments should not be construed as limiting the present invention, and the present invention will take the scope defined by the appended claims as the protection scope of the present invention.

Claims (4)

1. An identity recognition and information interaction platform based on an I ² C structural model, characterized in that it is composed of several PIC single-chip microcomputers that adopt an I ² C structural model interconnection mode and includes keyboards and displays connected with each PIC single-chip microcomputer The human-computer interaction module constitutes a network architecture, in which: Several PIC single-chip microcomputers are used for mutual identification and information exchange; Human-computer interaction module is used for data input and output. 2. I ² C structure model identity recognition and information interaction platform according to claim 1, it is characterized in that: the data bus SDA in the described I ² C structure model is: connected by every PIC microcontroller interface pin RC0 The data bus formed by the corresponding interconnection after the pull-up resistor; the timing bus SCL in the I ² C structure model is: the timing bus formed by the corresponding interconnection after the interface pin RC1 of each PIC microcontroller is connected with the pull-up resistor . 3. The I ² C structure model identity recognition and information interaction platform according to claim 1 or 2, characterized in that: the keyboard of the human-computer interaction module is a 4*4 matrix keyboard; the display is a 3-digit digital dynamic display . 4. A communication protocol unit for the identity recognition and information interaction platform described in claim 1 or 2 or 3, characterized in that it comprises a three-layer networked communication protocol: The first-layer protocol includes the frame header subroutine, the frame tail subroutine, and the subroutine for sending and receiving a byte of data. It is hardware-oriented and undertakes the function of operating the bus. It is the lowest-level physical transmission protocol or agreement; The second layer protocol includes data frames, and the information of one frame includes three parts of data content: the receiver ID identification code, the sender ID identification code and the data content to be sent. In addition, the data frame information will be the first layer The hardware processing operation in the protocol shields the third layer; The third-layer protocol is contained in the scanning module of the keyboard, and realizes the switching of the working state of the platform and the collection and display of data, and is an interactive protocol oriented to the application layer.

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