CN102523141B - Method for networking and cascading electronic equipment by using universal serial port technology - Google Patents

Abstract

The invention provides a method for cascading electronic devices in a network by using the general serial port technology, which consists of a computer general serial port, a master device port A, a master device port B, a master device level conversion unit, a master device control unit, a slave device Port A, slave device port B, slave device level conversion unit, slave device control unit, slave device optocoupler unit, the computer serial port is connected to the master device port A, the master device port B is connected to the slave device port A, and the slave device port B is connected to port A of the lower-level slave device. The computer sends data to each device in the form of broadcast, and the data returned by each device to the computer is in the form of time division multiplexing. The invention not only realizes the data transmission between the computer and each device, but also the method Simple, low cost, low development and debugging difficulty, easy maintenance.

Description

A method for cascading electronic device networking by using general serial port technology

technical field

The invention relates to the technical field of network cascading of electronic equipment, in particular to a method for cascading the network of electronic equipment by using the universal serial port technology.

Background technique

At present, the methods of networking and cascading of many electronic devices are through Ethernet, USB bus, I2C bus, CAN bus, USB and other methods. Although these methods can realize the cascading of electronic devices, they are complicated in technology, high in cost, The communication distance is short, and relay equipment is required. When computers communicate with electronic devices in a network, if they are cascaded through Ethernet, it is convenient and not limited by the number of cascaded devices. The support of CPU and related embedded applications, and the support of network switches is also required when multiple devices are networked. When using the I2C bus and CAN bus to form a network, the general-purpose computer does not have these two types of interfaces. To adopt these two types of bus networks, it is necessary to add third-party equipment to convert these two types of bus interfaces into computers. Some interfaces are limited by the number of devices and the communication distance when networking devices. Although the USB bus networking method is also very convenient, it also has higher requirements for the number of cascades, communication distance, and CPU and embedded programming of the device. When the above-mentioned methods are adopted at the same time, it is more difficult to develop and debug the application software on the computer side.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for cascading electronic equipment by using universal serial port technology to overcome the high requirements for equipment such as Ethernet, USB bus, I2C bus, CAN bus, etc. Due to the difficulty of debugging and the need for third-party equipment support, the present invention uses a general-purpose serial port as the cascading interface of the equipment, and the topological structure is a daisy chain mode. This cascading method does not require the support of third-party equipment, especially the CPU and software support requirements of the equipment are very low, and the difficulty of software development and debugging on the computer side is low.

The technical solution of the present invention to solve the above-mentioned technical problems is: a method for cascading electronic devices in a network by using the universal serial port technology, wherein the electronic devices include: a computer, a master device, several slave devices, each of the master device and the slave devices There are two general-purpose serial ports, namely port A and port B; the characteristic is that: the general-purpose serial port of the computer is connected to the port A of the master device, and the port B of the master device is connected to the port A of the first slave device. Port B of one slave device is connected to port A of the second slave device, and so on, all devices are connected in the form of daisy chain; each device has a CPU or FPGA as the control unit for sending and receiving data, and at the same time The data sent by all the slave devices can be connected together through the photocoupler device. Since the photocoupler device has the function of photoelectric isolation, all the data sent from the slave device to the computer can be connected to one point; in the master device and each slave device All have a level conversion circuit unit, which is used to convert the signal level to the level standard that the master device and the slave device can receive;

In this method, the universal serial port of the computer is cascaded through the daisy chain so that the sending end of the universal serial port of the computer is connected to the receiving ends of all devices through the master device at the same time, and the sending end of the universal serial port on the specific computer first enters the port of the master device A, and then inside the master device, connect the sending end of the computer’s universal serial port to port B of the master device, so the sending end of the computer’s universal serial port is output from the port B of the master device, and then connected to port A of the slave device 1, in the slave device Inside the port A of the device, connect this line to the port B of the slave device 1, then output from the port B of the slave device 1, connect to the port A of the slave device 2, and so on, thus forming a daisy chain connection form; the computer sends to The data of each device is sent in the form of broadcast;

In this method, the receiving end of the general-purpose serial port of the computer is connected to port A of the master device, and all the data sent from the slave device to the computer are forwarded to the computer by the master device; The chain mode is connected to the master device in a unified way; all devices cannot send data to the computer at the same time, but use time division multiplexing to send data to the computer; the master device and each slave device have the following two ways to send data to the computer One implementation: one way is determined by the gating command sent by the master device; the other way is to send the gating command by the computer, the sending of the gating command is in broadcast mode, and each device determines according to the received gating command Whether to send data to the computer.

Wherein, the level conversion unit between the master device and the slave device can add a photoelectric conversion module, so that the master device and the slave device are connected by optical fiber.

Among them, when the master device and each slave device send data to the computer, when the strobe command sent by the master device is determined, the strobe command is transmitted in the serial data format and through the RS232 level. sent at intervals.

Among them, the specific implementation method can be as follows: the general-purpose serial port of the computer is connected to the main equipment port A, the signal transmission between the main equipment port A and the main equipment port B, the main equipment level conversion, and the main equipment control unit is to convert the signal level to The level standard that both the computer and the master device can receive, and some signals are connected to the port B of the master device for the needs of device cascading; the port B of the master device is connected to the port A of the slave device 1, and the port A of the slave device 1 is connected to the port A of the slave device 1 Port B, the level conversion of slave device 1, and the signal transmission between the control unit of slave device 1 is to convert the signal level into a level standard that can be received by the master device, slave device 1, slave device 2, and computer. At the same time, some signals Connecting to port B of slave device 1 is for device cascading; port B of slave device 1 is connected to port A of slave device 2, port A of slave device 2 is connected to port B of slave device 2, level conversion of slave device 2, and port A of slave device 2 The signal transmission between the control units is to convert the signal level into a level standard that can be received by the master device, slave device 1, slave device 2, and computer. At the same time, some signals are connected to slave device 2 port B for device cascading Required; the control unit of slave device 1 is connected to the optocoupler device of slave device 1, and the output of the photocoupler device of slave device 1 is connected to port B of slave device 1 and port A of slave device 1; the control unit of slave device 2 is connected to the photocoupler device of slave device 2 , the optocoupler device of slave device 2 is connected to port B of slave device 2 and port A of slave device 2; through the connection of port B of master device, port B of slave device 1 and port A of slave device 2, the optocoupler device of slave device 1 is realized The output and output of the slave device 2 photocoupler are simultaneously connected to the control unit of the master device; on the entire link, there are 4 data flow signals; the first data flow signal is a signal sent from the general serial port of the computer through the The cascade connection is transmitted to the master device and each slave device in the form of broadcast, and then enters the control unit of each device through their own level conversion; the second data flow signal is the signal sent from the master device control unit through the master device circuit Level conversion, master device port B cascades to each slave device, transmits to each slave device in the form of broadcast, and then enters the control unit of each slave device through the level conversion of each slave device; the third data flow signal is the slave device After the control unit of each slave device passes through the action of the optocoupler, it enters the control unit of the master device after the cascading of each device; the fourth data flow signal is sent from the control unit of the master device, and enters the master device through the level conversion of the master device. After the device port B and the main device port A, connect to the general-purpose serial port of the computer; through the transmission of these 4-way data stream signals, the data exchange between the computer and each device can be realized, and the use of general-purpose serial port technology to make the electronic equipment network-level couplet.

Wherein, on the basis of realizing the cascading of three devices in the above method, multiple devices can be cascaded as required.

The advantages of the present invention compared with prior art are as follows:

1. The interface technology adopted in the present invention is simple, and it is not difficult for circuit design and software development. At the same time, because the circuit is simple, the implementation cost is low and the reliability is high;

2. The computers of the present invention all have a general-purpose serial port, even if there is no standard serial port, it can be realized through the USB-to-serial port mode, and no expensive third-party equipment is needed;

3. The application of the present invention is flexible, and the transmission protocol can be flexibly designed according to actual needs.

Description of drawings

Fig. 1 is a functional block diagram of the present invention.

Fig. 2 is an electrical schematic diagram of an implementation example of the present invention.

In the figure, 1 is the general serial port of the computer; 2 is the port A of the master device; 3 is the port B of the master device; 4 is the level conversion of the master device; 5 is the control unit of the master device; 6 is port A of the slave device 1; 7 is the slave device 1 port B; 8 is the level conversion of slave device 1; 9 is the control unit of slave device 1; 10 is the photocoupler device of slave device 1; 11 is port A of slave device 2; 12 is port B of slave device 2; 13 is the slave device 2 level conversion; 14 is the control unit of the slave device 2; 15 is the photocoupling device of the slave device 2.

Detailed ways

Embodiments of the present invention are now described in conjunction with the accompanying drawings. But following embodiment only limits to explain the present invention, and protection scope of the present invention should comprise the whole content of claim, and promptly can realize the whole content of claim of the present invention to those skilled in the art through following embodiment.

In Figure 1, the electronic equipment includes: a computer, a master device, and several slave devices. The master device and the slave device each have two general-purpose serial ports, respectively port A and port B; computer general-purpose serial port 1 and master device port A 2 Connected, the signal transmission between the main equipment port A 2 and the main equipment port B 3, the main equipment level conversion 4, and the main equipment control unit 5 is to convert the signal level into a level standard that both the computer and the main equipment can receive. At the same time, some signals are connected to the main device port B3 for the needs of device cascading. The master device port B 3 is connected to the slave device 1 port A 6, the signal transfer between the slave device 1 port A 6 and the slave device 1 port B 7, the slave device 1 level conversion 8, and the slave device 1 control unit 9 is to transfer the signal The level is converted to a level standard that can be received by the master device, the slave device, and the computer. At the same time, some signals are connected to the slave device 1 port B 7 for the needs of device cascading. From equipment 1 port B 7 is connected with equipment 2 port A 11, from equipment 2 port A 11 and from equipment 2 port B 12, from equipment 2 level conversion 13, from equipment 2 control unit 14, the signal transfer is to be The signal level is converted to a level standard that can be received by the master device, the slave device, and the computer. At the same time, some signals are connected to the slave device 2 port B 12 for the needs of device cascading. The slave device 1 control unit 9 is connected with the slave device 1 photocoupler 10, and the output from the device 1 photocoupler 10 is connected to the slave device 1 port B 7 and the slave device 1 port A 6. From equipment 2 control unit 14 is connected with equipment 2 optocoupler 15, from equipment 2 optocoupler 15 is connected to equipment 2 port B 12 and from equipment 2 port A 11. Through the connection of the master device port B 3 with the slave device 1 port B 7 and the slave device 2 port A11, the slave device 1 photocoupler 10 output and the slave device 2 photocoupler 15 output are simultaneously connected to the master device control unit 5 superior. Throughout the link, there are 4 data flow signals. The first data flow signal is the signal sent from the general-purpose serial port 1 of the computer, which is transmitted to the master device and each slave device in the form of broadcast through the cascade connection between each device, and then enters the control unit of each device through their own level conversion; The 2nd road data flow signal is that the signal that sends out from master equipment control unit 5 passes through master equipment level conversion 4, master equipment port B 3 cascades to each slave equipment, transmits to each slave equipment with the form of broadcasting, then passes through each slave equipment The level conversion of the slave device enters the control unit of each slave device; the third data flow signal is sent from the control unit of each slave device after the action of the optocoupler, and then cascaded by each device and then enters the master device control unit 5 The 4th road data stream signal is sent out from the main equipment control unit 5, after entering the main equipment port B3 and the main equipment port A2 through the main equipment level conversion 4, it is connected to the general serial port 1 of the computer. Through the transmission of these 4-way data stream signals, data exchange between the computer and each device can be realized. In Figure 1, only three devices are cascaded, and multiple devices can be cascaded as required.

The electrical schematic diagram in Figure 2 is an electrical schematic diagram of a device. In the figure, the device can be set as a master device or a slave device by setting some jumpers. In the implementation example in Figure 2, through the jumper settings of J2, J4, J5, J6 and the mode setting of SW1, the same circuit can be used to make the device both as a master device and as a slave device, which achieves the application flexibility.

The two main operations of this embodiment are as follows:

(1) The computer sends data to each device

When the computer sends data to each device, the data passes through the above-mentioned first data flow signal. Combining with Figure 2, for each device, the signal sent by the computer to each device first passes through J1 and then enters IC1, and then enters IC3 after the level conversion of IC1. In IC3, it is determined whether the received data is for its own use according to the information contained in the data.

(2) Each device returns data to the computer

The process of returning data from each device to the computer must be completed through the above-mentioned 3-way data stream signals. First, the master device sends a strobe signal to each slave device through the second data flow signal. After each slave device receives the strobe signal, the control unit of the slave device determines whether it should return data to the computer at this time. If it is necessary to return data to the computer, the returned data is transmitted to the master device control unit 5 through the third data stream signal, and the master device control unit 5 returns the received slave device data to the computer through the fourth data stream signal.

As shown in Figure 2, J1 is an RJ45 socket, which is used as port A of the device; J3 is an RJ45 socket, which is used as port B of the device; IC1 is Maxim's MAX3250, which is used as a level conversion module of the device; IC2 is TLP421- 1. As the optocoupler unit of the slave device; IC3 uses Xilinx’s Spartan III series XC3S1000-4FT256 as the control unit of each device. When the circuit device shown in Figure 2 is used as the master device, firstly, through the mode setting function of the DIP switch of SW1, IC3 is switched to the master device working mode. Pin 2 of J1 is connected to pin 2 of the general-purpose serial port of the computer, which is the receiving end of the general-purpose serial port of the computer, and pin 3 of J1 is connected to pin 3 of the general-purpose serial port of the computer, which is the sending end of the general-purpose serial port of the computer. Pins 2 and 3 of J1 are connected to pins 17 and 19 of IC1 at the same time; two IO pins of IC3 are connected to pins 4 and 2 of IC1, so that the RS232 level and the level of J1 are realized through IC1. The conversion of the TTL level on the IC3 side realizes the data communication between IC3 and the computer, that is, the data communication between the master device and the general serial port of the computer. Because the current device is the main device, one IO pin of IC3 is connected to pin 5 of IC1, so that IC1 converts the TTL signal output by IC3 into an RS232 signal and outputs it through pin 16 of IC1, and at the same time connects pins 2 and 3 of J2 The pins are short-circuited with a short-circuit cap, so that this signal is connected to J3, and this signal can be used as a strobe signal for the return data of the slave device. Short-circuit J4, J5, and J6 with short-circuit caps, so as to realize the connection of all slave device optocoupler output signals at the master device end, and connect them to an IO pin of IC3, so that the master device can receive all slave devices returned data. The signals on J1 and J3 are connected to each other, so that the daisy chain cascade of multiple devices can be realized. When the circuit device shown in Figure 2 is used as a slave device, IC3 is switched to the slave device working mode through the mode setting function of SW1 first. J1 is connected to J3 of the master device outside the device, so that the slave device can receive the data sent by the computer at first. The conversion of RS232 signal and TTL signal is the same as that of the master device. The slave device needs to receive the strobe signal sent by the master device, so it is necessary to short-circuit the 1 and 2 pins of J2 with a short-circuit cap, because on the master device, the 2 and 3 pins of J2 are short-circuited, so when the master device After cascading with the slave device, the strobe signal sent from pin 16 of IC1 on the master device is connected to pin 18 of IC1 of the slave device, and then IC1 converts the RS232 level signal into a TTL signal, It is output from pin 3 of IC1 and connected to an IO pin of IC3, so that the slave device can receive the strobe signal sent by the master device. To send data from the slave device to the master device, in addition to timely sending according to the received strobe signal, it is also necessary to keep J4, J5, and J6 in an open state, and the data sent by the slave device is output to IC2 through an IO pin of IC3 superior. Since J4, J5, and J6 at the master device end are in a short-circuit state, all the signals output from the slave device are isolated by IC2, connected together at the master and backup ends, and can be received by the master device. When multiple slave devices are cascaded, it is necessary to connect J3 of the previous slave device to J1 of the next slave device outside the device.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention.

Claims (4)

1. by using universal serial port technology to make a method for electronic equipment networking cascade, wherein, electronic equipment comprises: computer, a main equipment, some from equipment, and main equipment and respectively have two universal serial port ports from equipment, is respectively port A and port B; It is characterized in that: the universal serial port of computer is connected on the port A of main equipment, the port B of main equipment is connected to first from the port A of equipment, first port B from equipment is connected to second from the port A of equipment, the like, connect all devices with the form of daisy chain; In each equipment, there is a CPU or the FPGA control unit as transceiving data, by photoelectric coupled device, all data that send from equipment can be connected together simultaneously, because photoelectric coupled device has the effect of photoelectricity isolation, therefore allly send to the data of computer to be connected to any from equipment to be achieved; At main equipment and eachly have a level shifting circuit unit from equipment, for the level standard that signal level is converted to main equipment, can receives from equipment;

The universal serial port of the method Computer is connected on the receiving terminal of all devices the transmitting terminal of computer general-purpose serial ports by this cascade system of daisy chain simultaneously by main equipment, on concrete computer, first the transmitting terminal of universal serial port enters into main equipment port A, then in main equipment inside, the transmitting terminal of computer general-purpose serial ports is connected on main equipment port B, therefore the transmitting terminal of computer general-purpose serial ports is exported from main equipment port B, and then be connected to from equipment 1 port A, again this line is being connected to from equipment 1 port B from device port A inside, afterwards again from exporting from equipment 1 port B, be connected to from equipment 2 port A, the like, thereby form the type of attachment of daisy chain, the data that computer sends to each equipment are to send with the forms of broadcasting,

The receiving terminal of the universal serial port of the method Computer is connected to main equipment port A, allly sends to the data of computer to be all transmitted to computer by main equipment from equipment; Allly send to the data of computer to export by photoelectric coupled device from equipment, be then connected on main equipment by daisy chaining unification; All equipment can not send data to computer simultaneously, but adopts time-multiplexed mode to send data to computer; Main equipment and eachly when send data to computer from equipment and have one of following two kinds of modes to realize: a kind of mode is that the gating instruction that main equipment sends determines; Another kind of mode be to send gating instruction by computer, this gating instruction be sent as broadcast mode, each equipment determines whether to computer transmission data according to the gating instruction receiving;

Concrete methods of realizing can be as follows: computer general-purpose serial ports (1) and main equipment port A(2) be connected, main equipment port A(2) and main equipment port B(3), signal transmission between main equipment level conversion (4), main equipment control unit (5) is that signal level is converted to the level standard that computer and main equipment can receive, some signals are connected to main equipment port B(3 simultaneously) be the needs for equipment cascading; Main equipment port B(3) with from equipment 1 port A(6) be connected, from equipment 1 port A(6) and from equipment 1 port B(7), be the level standard that signal level is converted to main equipment, can receives from equipment 1, from equipment 2, computer from equipment 1 level conversion (8), from the signal transmission between equipment 1 control unit (9), simultaneously some signals are connected to from equipment 1 port B(7) be the needs for equipment cascading; From equipment 1 port B(7) with from equipment 2 port A(11) be connected, from equipment 2 port A(11) and from equipment 2 port B(12), be the level standard that signal level is converted to main equipment, can receives from equipment 1, from equipment 2, computer from equipment 2 level conversion (13), from the signal transmission between equipment 2 control units (14), simultaneously some signals are connected to from equipment 2 port B(12) be the needs for equipment cascading; From equipment 1 control unit (9) be connected from equipment 1 photoelectric coupled device (10), be connected to from equipment 1 port B(7 from equipment 1 photoelectric coupled device (10) output) and from equipment 1 port A(6); From equipment 2 control units (14) be connected from equipment 2 photoelectric coupled devices (15), be connected to from equipment 2 port B(12 from equipment 2 photoelectric coupled devices (15)) and from equipment 2 port A(11); By main equipment port B(3) with from equipment 1 port B(7), from equipment 2 port A(11) be connected, having realized will be from equipment 1 photoelectric coupled device (10) output, be connected to main equipment control unit (5) from equipment 2 photoelectric coupled devices (15) output simultaneously; On whole link, there are 4 circuit-switched data stream signals; The 1st circuit-switched data stream signal is that the signal sending out from computer general-purpose serial ports (1) is transferred to main equipment and respectively from equipment, then enters into the control unit of each equipment through level conversion separately with the forms of broadcasting by the cascade of each equipment room; The 2nd circuit-switched data stream signal is signal process main equipment level conversion (4), the main equipment port B(3 sending out from main equipment control unit (5)) be cascaded to respectively from equipment, be transferred to respectively from equipment, then through respectively entering into the respectively control unit from equipment from the level conversion of equipment with the form of broadcast; The 3rd circuit-switched data stream signal is from respectively sending through after optocoupler effect from the control unit of equipment, then by the laggard device control cell (5) of becoming owner of of cascade of each equipment; The 4th circuit-switched data stream signal is to send out from main equipment control unit (5), enters main equipment port B(3 through main equipment level conversion (4)), main equipment port A(2) after, be connected on computer general-purpose serial ports (1); The transmission of this 4 circuit-switched data stream signal of process, just can realize computer and each equipment carries out exchanges data, has realized use universal serial port technology and has made electronic equipment networking cascade.

2. according to claim 1 a kind of by using universal serial port technology to make the method for electronic equipment networking cascade, it is characterized in that: main equipment and can increase photoelectric conversion module from the level conversion unit between equipment, makes main equipment and from using optical fiber to connect between equipment.

3. according to claim 1 a kind of by using universal serial port technology to make the method for electronic equipment networking cascade, it is characterized in that: main equipment and each mode that when sends data to computer from equipment are that gating instruction that main equipment sends is while determining, this gating instruction is with serial data form, transmits by RS232 level, and uniformly-spaced the time sends in this gating instruction.

4. according to claim 1 a kind of by using universal serial port technology to make the method for electronic equipment networking cascade, it is characterized in that: realize in method described in claim 1 on the basis of 3 equipment cascadings and can carry out as required multiple equipment cascadings.

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