An LVDS-based SPI ring communication network system and communication method

Abstract

This invention discloses an LVDS-based SPI ring high-speed backplane communication network system. The system includes a master station, multiple slave stations, and one terminal module. The master station includes a controller and a master station base; each slave station includes a slave station base and an I / O module. The controller, master station base, slave station bases, I / O module, and terminal module form an LVDS ring communication link and an SPI communication control link (SPICTLN), collectively constituting the LVDS-based SPI ring communication network system. This invention solves the problems of slow communication speed and short SPI communication distance in traditional communication methods such as CAN, RS-485, and UART. All I / O modules support hot-swapping, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of industrial automation, and more specifically to an SPI ring high-speed backplane communication network system based on LVDS. Background Technology

[0002] In the field of industrial automation, data exchange between the controller and I / O modules of a programmable logic controller (PLC) typically uses communication methods such as CAN, RS-485, SPI, and UART. However, with the continuous development of industry, the communication speed required for data exchange is increasing, the amount of communication data is also increasing, and the requirements for the anti-interference capability of the communication bus are also becoming more stringent. Traditional communication methods such as CAN, RS-485, and UART have problems with slow communication speeds, and SPI has problems with short communication distances, making it difficult to meet the information exchange needs of industrial control. Existing FPGA-based M-LVDS multi-node communication bus solutions suffer from the high cost of FPGAs, and the I / O modules must also support hot-swapping functionality for plug-and-play operation, ensuring that system maintenance does not affect normal system operation. Therefore, existing communication bus solutions are no longer sufficient. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies and provide an SPI ring high-speed backplane communication network system based on LVDS. This system not only solves the problems of slow communication speed and short SPI communication distance of traditional communication methods such as CAN, RS-485 and UART, but also requires each IO module to support hot-swapping, eliminates the need for address identification circuits, and has a lower cost.

[0004] To achieve the above, the technical solution of the present invention is as follows:

[0005] An LVDS-based SPI ring communication network system includes a master station, slave stations, and a terminal module. The master station includes a connected controller and a master station base. There are multiple slave stations, each of which includes a slave station base and an I / O module. Each slave station base is connected to its corresponding I / O module. The controller and each I / O module are equipped with SPI communication circuits. The master station base and each slave station base are equipped with LVDS communication circuits and SPI bus control circuits. The terminal module is equipped with an LVDS loopback circuit and an SPI communication control loopback circuit.

[0006] The controller's SPI communication circuit is connected to the LVDS communication circuit of the master station base to form the master station LVDS communication link LVDSX; in each slave station base, the SPI communication circuit of the IO module and the LVDS communication circuit of the corresponding slave station base form the slave station LVDS communication link LVDSN; the master station LVDS communication link LVDSX and each slave station LVDS communication link LVDSN are cascaded in sequence and then connected to the LVDS loop circuit of the terminal module to form an LVDS ring communication link.

[0007] The controller's SPI communication circuit and the master station's SPI bus control circuit are connected to form an SPI communication control link SPICTLX; in each slave station's base, the SPI communication circuit of the IO module ION is connected to the corresponding slave station's SPI bus control circuit to form an SPI communication control link SPICTLN; the SPI communication control link SPICTLX and the SPI communication control link SPICTLN of each slave station are cascaded in sequence and then connected to the SPI communication control loop circuit of the terminal module to form an SPI ring communication control link.

[0008] The LVDS ring communication link and the SPI ring communication control link together form the LVDS-based SPI ring communication network system.

[0009] Furthermore, the aforementioned master station base includes LVDS communication circuits DIFIX and DIFOX; the controller includes SPI communication circuit SIGX; each slave station base BN includes LVDS communication circuits DIFIN and DIFON, and the corresponding IO module ION includes SPI communication circuit SIGN, where N represents the slave station base number; the terminal module includes an LVDS loopback circuit.

[0010] The MOSI signal of the controller's SPI communication circuit SIGX is connected to the single-ended input port RIX of the master station's LVDS communication circuit DIFIX, converting the SPI single-ended signal into the LVDS differential signal RIX-LVDS; the MISO signal of the controller's SPI communication circuit SIGX is connected to the single-ended output port ROX of the master station's LVDS communication circuit DIFIX, converting the LVDS differential signal ROX-LVDS into the SPI single-ended signal; the two signal conversions form the master station LVDS communication link LVDSX.

[0011] The MOSI signal of the SPI communication circuit SIGN of each IO module ION is connected to the single-ended input port RIN of the LVDS communication circuit DIFIN of the corresponding slave base BN, converting the SPI single-ended signal into the LVDS differential signal RIN-LVDS; the MISO signal of the SPI communication circuit SIGN of each IO module ION is connected to the single-ended output port RON of the LVDS communication circuit DIFON of the corresponding slave base BN, converting the LVDS differential signal RON-LVDS into the SPI single-ended signal; the signal conversion forms the slave LVDS communication link LVDSN;

[0012] The LVDS differential signal RIX-LVDS of the master station LVDS communication link LVDSX is cascaded with the LVDS differential signal RON-LVDS of each slave station base in sequence, and then connected to the LVDS differential signal ROX-LVDS of the master station base through the LVDS loop circuit of the terminal module, finally forming an LVDS ring communication link.

[0013] Furthermore, the master station base also includes an SPI bus control circuit BUSX; each slave station base BN also includes an SPI bus control circuit BUSN; and the terminal module also includes an SPI communication control loop circuit.

[0014] The SCK-X, EN-X, and CK-X of the controller's SPI communication circuit SIGX are connected to the SPI bus control circuit BUSX of the master station base to form an SPI communication control link SPICTLX; the SCK-N, EN-N, and CK-N of the SPI communication circuit SIGN of each IO module ION are connected to the SPI bus control circuit BUSN of the corresponding slave station base BN to form an SPI communication control link SPICTLN; the SPI communication control link SPICTLX and each SPI communication control link SPICTLN are cascaded in sequence, and then connected to the SPI communication control loop circuit of the terminal module to form an SPI ring communication control link.

[0015] Furthermore, each slave station base BN also includes a single-pole double-throw switch SWN, which is connected to the corresponding LVDS communication circuits DIFIN and DIFON to form a hot-swappable circuit.

[0016] Furthermore, the number of stations is 16.

[0017] This invention also provides a communication method for the aforementioned LVDS-based SPI ring communication network system. The master station sends an address registration message through the LVDS-based SPI ring communication network system, with the message frame header consisting of one byte of address data. Each slave station sequentially adds an address digit to the message data frame header according to the connection order of the LVDS-based SPI ring communication network system, until the last slave station adds an address digit to the message data frame header and sends it back to the master station, thus enabling the master station to obtain the addresses of each slave station. After obtaining the slave station addresses, the master station sends an IO module parameter acquisition message through the LVDS-based SPI ring communication network system. Each slave station sequentially adds IO module parameters to the message data according to the connection order of the LVDS-based SPI ring communication network system, until the last slave station adds IO module parameters to the message data, and finally returns the message to the master station through the terminal module, thus achieving IO module parameter acquisition.

[0018] The present invention has the following advantages over the prior art:

[0019] This invention presents an LVDS-based SPI ring high-speed backplane communication network system, which not only solves the problems of slow communication speed and short SPI communication distance of traditional communication methods such as CAN, RS-485 and UART, but also supports hot-swapping of I / O modules, improving system stability. Compared with the M-LVDS multi-node bus communication system using FPGA, it has the advantage of lower cost. Attached Figure Description

[0020] Figure 1 This is an overall architecture diagram of an SPI ring high-speed backplane communication network system based on LVDS provided by the present invention;

[0021] Figure 2 This is a schematic diagram of an SPI ring high-speed backplane communication network system structure based on LVDS provided by the present invention;

[0022] Figure 3 This invention provides a network architecture diagram of an LVDS-based SPI ring high-speed backplane communication network, including an LVDS ring communication link and an SPI ring communication link.

[0023] Figure 4 This invention provides an LVDS ring communication link topology diagram for SPI ring high-speed backplane communication based on LVDS.

[0024] Figure 5 This invention provides an SPI ring communication control link topology diagram for LVDS-based SPI ring high-speed backplane communication.

[0025] Figure 6This is a diagram of a hot-swappable network architecture for an SPI ring high-speed backplane communication network based on LVDS, provided by the present invention. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0027] The LVDS-based SPI ring high-speed backplane communication network system provided by this invention includes a master station, a terminal module, and 16 slave stations (the number of slave stations can be selected according to requirements; this embodiment uses 16 slave stations as an example). The overall architecture diagram of the system is shown below. Figure 1 As shown in the diagram. The master station includes a controller and a master station base; the Nth slave station includes a slave station base BN and an IO module ION, where N is a natural number representing the slave station's number. The system's structural diagram is shown below. Figure 2 As shown.

[0028] Firstly, regarding the structure of the LVDS-based SPI ring high-speed backplane communication network system:

[0029] The master station base is located at the beginning of the system. The master station base is connected to slave station base B1, slave station base B1 is connected to slave station base B2, and so on, with slave station bases BN cascading sequentially. The 16th slave station base BN16 is connected to the terminal module. The controller is connected to the master station base. IO module IO1 is connected to slave station base B1, IO module IO2 is connected to slave station base B2, and so on. The Nth IO module ION is connected to the Nth slave station base BN, where N is a natural number representing the slave station number.

[0030] The communication network system design of the above system includes an LVDS ring communication link and an SPI ring communication control link. The specific communication link architecture diagram is shown below. Figure 3 As shown:

[0031] Regarding LVDS ring communication links:

[0032] The master station base includes LVDS communication circuits DIFIX and DIFOX, the controller includes SPI communication circuit SIGX, the Nth slave station base BN includes LVDS communication circuits DIFIN and DIFON and SPI bus control circuit BUSN, the Nth IO module ION includes SPI communication circuit SIGN; the terminal module includes LVDS loopback circuit and SPI communication control loopback circuit.

[0033] like Figure 4As shown, the MOSI signal of the controller's SPI communication circuit SIGX is connected to the single-ended input port RIX of the master station's LVDS communication circuit DIFIX, converting the SPI single-ended signal into the LVDS differential signal RIX-LVDS. The MISO signal of the controller's SPI communication circuit SIGX is connected to the single-ended output port ROX of the master station's LVDS communication circuit DIFIX, converting the LVDS differential signal ROX-LVDS back into an SPI single-ended signal. These two signal conversions form the master station's LVDS communication link LVDSX.

[0034] The MOSI signal of the SPI communication circuit SIGN of the Nth IO module ION is connected to the single-ended input port RIN of the LVDS communication circuit DIFIN of the Nth slave base BN, converting the SPI single-ended signal into the LVDS differential signal RIN-LVDS. The MISO signal of the SPI communication circuit SIGN of the Nth IO module ION is connected to the single-ended output port RON of the LVDS communication circuit DIFON of the Nth slave base BN, converting the LVDS differential signal RON-LVDS back into the SPI single-ended signal. These two signal conversions form the slave LVDS communication link LVDSN.

[0035] The master station LVDS communication link LVDSX is connected to the first slave station LVDS communication link LVDS1. The first slave station LVDS communication link LVDS1 is connected to the second slave station LVDS communication link LVDS2, and so on. The 16th slave station LVDS communication link LVDS16 is connected to the LVDS loop circuit of the terminal module to form an LVDS ring communication link. In detail, the LVDS differential signal RIX-LVDS of the master station base is connected to the LVDS differential signal RO1-LVDS of the first slave station base. The LVDS differential signal RI1-LVDS of the first slave station base is connected to the LVDS differential signal RO2-LVDS of the second slave station base. The LVDS differential signal RI2-LVDS of the second slave station base is connected to the LVDS differential signal RO3-LVDS of the third slave station base, and so on. The LVDS differential signal RI16-LVDS of the sixteenth slave station base is connected to the LVDS differential signal ROX-LVDS of the master station base through the LVDS loop circuit of the terminal module, thus forming an LVDS ring communication link.

[0036] Regarding the SPI ring communication control link:

[0037] like Figure 5As shown, the SCK-X, EN-X, and CK-X of the controller's SPI communication circuit SIGX are connected to the SPI bus control circuit BUSX of the master station base to form the SPI communication control link SPICTLX. The SCK-N, EN-N, and CK-N of the SPI communication circuit SIGN of the Nth IO module ION are connected to the SPI bus control circuit BUSN of the Nth slave station base BN to form the SPI communication control link SPICTLN. The SPI communication control link SPICTLX is connected to the SPI communication control link SPICTL1 of the first slave station. The SPI communication control link SPICTL1 of the first slave station is connected to the SPI communication control link SPICTL2 of the second slave station, and so on, cascading sequentially. The SPI communication control link SPICTL16 of the 16th slave station is connected to the SPI communication control loop circuit of the terminal module to form the SPI ring communication control link. SCK-X and SCK-N are SPI communication clock signals used to control the timing of SPI ring communication. EN-X and EN-N are SPI communication trigger signals used to notify the slave station that data is ready. CK-X and CK-N are SPI ring start signals used to start SPI ring communication.

[0038] The Nth slave station base BN includes a single-pole double-throw switch SWN. The single-pole double-throw switch SWN is connected to the LVDS communication circuits DIFIN and DIFON to form a hot-swappable circuit, as shown in the schematic diagram. Figure 6 As shown. When no IO module ION is installed on the slave base BN, the single-pole double-throw switch SWN shorts the LVDS communication circuits DIFIN and DIFON, which is equivalent to a signal bridging. When the IO module ION is installed on the slave base BN, the LVDS communication circuits DIFIN and DIFON are cascaded with other LVDS communication circuits to achieve LVDS signal transmission.

[0039] Regarding obtaining slave address and IO module parameters:

[0040] The master station sends an address registration message through the LVDS-based SPI ring communication network system described above. The header of the message contains one byte of address data, which is 0000 0000 at this time. The slave stations sequentially add address bits to the header of the message data frame according to the connection order of the LVDS-based SPI ring communication network system. For example, slave station 1 adds 1 to the header of the address registration message, becoming 0000 0001, slave station 2 adds 1 to the header of the address registration message, becoming 0000 0011, and so on, until slave station 16 adds 1 to the header of the address registration message, becoming 0001 0000, and sends it back to the master station, thus enabling the master station to obtain the addresses of each slave station.

[0041] After obtaining the slave station's address, the master station sends an IO module parameter acquisition message through the LVDS-based SPI ring communication network system of this invention. The slave station adds the IO module parameters to the message data sequentially according to the connection order of the LVDS-based SPI ring communication network system. Specifically, slave station 1 adds the IO module parameters after address bit 0000 0001, slave station 2 adds the IO module parameters after address bit 0000 0011, and so on, until slave station 16 adds the IO module parameters after address bit 0001 0001. Finally, the message is returned to the master station through the terminal module, thus realizing the acquisition of IO module parameters.

[0042] This invention provides an LVDS-based SPI ring high-speed backplane communication network system. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. An SPI ring communication network system based on LVDS, characterized in that, It includes a master station, slave stations, and a terminal module; the master station includes a connected controller and a master station base; there are multiple slave stations, each of which includes a slave station base and an I / O module, and each slave station base is connected to a corresponding I / O module; the controller and each I / O module are equipped with an SPI communication circuit, the master station base and each slave station base are equipped with an LVDS communication circuit and an SPI bus control circuit, and the terminal module is equipped with an LVDS loopback circuit and an SPI communication control loopback circuit; The controller's SPI communication circuit is connected to the LVDS communication circuit of the master station base to form the master station LVDS communication link LVDSX. In each slave station base, the SPI communication circuit of the IO module and the LVDS communication circuit of the corresponding slave station base form each slave station LVDS communication link LVDSN; the master station LVDS communication link LVDSX and each slave station LVDS communication link LVDSN are cascaded in sequence and then connected to the LVDS loop circuit of the terminal module to form an LVDS ring communication link. The controller's SPI communication circuit and the master station's SPI bus control circuit are connected to form an SPI communication control link SPICTLX; in each slave station, the SPI communication circuit of the IO module ION is connected to the corresponding slave station's SPI bus control circuit to form an SPI communication control link SPICTLN; the SPI communication control link SPICTLX and the SPI communication control link SPICTLN of each slave station are cascaded in sequence and then connected to the SPI communication control loop circuit of the terminal module to form an SPI ring communication control link. The LVDS ring communication link and the SPI ring communication control link constitute the LVDS-based SPI ring communication network system. The master station base includes LVDS communication circuits DIFIX and DIFOX; the controller includes SPI communication circuit SIGX; each slave station base BN includes LVDS communication circuits DIFIN and DIFON, and the corresponding IO module ION includes SPI communication circuit SIGN, where N represents the slave station base number; the terminal module includes an LVDS loopback circuit. The MOSI signal of the controller's SPI communication circuit SIGX is connected to the single-ended input port RIX of the master station's LVDS communication circuit DIFIX, converting the SPI single-ended signal into the LVDS differential signal RIX-LVDS; the MISO signal of the controller's SPI communication circuit SIGX is connected to the single-ended output port ROX of the master station's LVDS communication circuit DIFIX, converting the LVDS differential signal ROX-LVDS into the SPI single-ended signal; these two signal conversions form the master station's LVDS communication link LVDSX. The MOSI signal of the SPI communication circuit SIGN of each IO module ION is connected to the single-ended input port RIN of the LVDS communication circuit DIFIN of the corresponding slave base BN, converting the SPI single-ended signal into the LVDS differential signal RIN-LVDS; the MISO signal of the SPI communication circuit SIGN of each IO module ION is connected to the single-ended output port RON of the LVDS communication circuit DIFON of the corresponding slave base BN, converting the LVDS differential signal RON-LVDS into the SPI single-ended signal; the signal conversion forms the slave LVDS communication link LVDSN; The LVDS differential signal RIX-LVDS of the master station LVDS communication link LWDSX is cascaded with the LVDS differential signal RON-LVDS of each slave station base in sequence, and then connected to the LVDS differential signal ROX-LVDS of the master station base through the LVDS loop circuit of the terminal module, finally forming an LVDS ring communication link. The master station base also includes an SPI bus control circuit BUSX; each slave station base BN also includes an SPI bus control circuit BUSN; the terminal module also includes an SPI communication control loop circuit. The SCK-X, EN-X, and CK-X of the controller's SPI communication circuit SIGX are connected to the SPI bus control circuit BUSX of the master station base to form an SPI communication control link SPICTLX; the SCK-N, EN-N, and CK-N of the SPI communication circuit SIGN of each IO module ION are connected to the SPI bus control circuit BUSN of the corresponding slave station base BN to form an SPI communication control link SPICTLN; the SPI communication control link SPICTLX and each SPI communication control link SPICTLN are cascaded in sequence, and then connected to the SPI communication control loop circuit of the terminal module to form an SPI ring communication control link.

2. The LVDS-based SPI ring communication network system according to claim 1, characterized in that, Each slave station base BN also includes a single-pole double-throw switch SWN, which is connected to the corresponding LVDS communication circuits DIFIN and DIFON to form a hot-swappable circuit.

3. The LVDS-based SPI ring communication network system according to claim 1 or 2, characterized in that, The number of slave stations is 16.

4. The communication method of the LVDS-based SPI ring communication network system as described in claim 1 or 2, characterized in that: The master station sends an address registration message through the LVDS-based SPI ring communication network system, with the message frame header consisting of one byte of address data. Each slave station adds an address digit to the message data frame header sequentially according to the connection order of the LVDS-based SPI ring communication network system, until the last slave station adds an address digit to the message data frame header and then sends it back to the master station, thus enabling the master station to obtain the addresses of each slave station. After obtaining the slave station addresses, the master station sends an IO module parameter acquisition message through the LVDS-based SPI ring communication network system. Each slave station adds IO module parameters to the message data sequentially according to the connection order of the LVDS-based SPI ring communication network system, until the last slave station adds IO module parameters to the message data, and finally returns the message to the master station through the terminal module, thus achieving the acquisition of IO module parameters.

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