Fault state information acquisition interface with hot plug capability

Abstract

The invention provides a fault state information acquisition interface with hot plug capability, and belongs to the technical field of airborne computers, the fault state information acquisition interface specifically comprises a long and short pin connector, an interface protection circuit and an RS422 transceiver which are connected in sequence, and the RS422 transceiver is provided with an ESD protection module; the long and short pin connector comprises a long pin and a short pin, the long pin is defined as a shielding ground, and the short pin is defined as a differential signal in an RS422 bus interface; the interface protection circuit comprises a receiving end and a transmitting end, the receiving end is provided with a receiving end transient voltage protection device and a receiving end terminating resistor, and the transmitting end is provided with a transmitting end transient voltage protection device and a transmitting end terminating resistor. Through the processing scheme provided by the invention, the fault site information can be conveniently obtained, the later troubleshooting and reproduction work of the fault is facilitated, and the interface security is improved.

Description

Technical Field

[0001] The present application relates to the technical field of airborne computers, and in particular to a fault status information collection interface with hot-swap capability. Background Art

[0002] In the field of avionics, the testability requirements for airborne computer equipment are very high. When an airborne computer fails, it must be able to accurately locate and store the reported fault to facilitate later troubleshooting and maintenance. In most cases, the airborne computer uses an external high-speed bus to communicate with the host computer and report its own working conditions. When the external bus communication is interrupted, the host computer cannot obtain the working and health status of the lower computer, and cannot obtain relevant fault information.

[0003] Ordinary airborne computer maintenance interfaces do not support hot-swap operations. When using this type of interface to establish an external bus path, the airborne computer must be powered on and off, which may cause damage to the fault site of sporadic faults. Even if the bus data path is established after the product is powered on again, the fault site information of the sporadic fault cannot be obtained, which makes subsequent troubleshooting and fault reproduction difficult. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a fault status information collection interface with hot-swappable capability. When an external bus communication fails, this interface can be used. While avoiding powering on and off the product and destroying the fault site, the on-board computer fault information collection interface technology that supports hot-swappable operation can be used to obtain the current product status information at any time through the interface, and the fault site information can be retained. The interface can be used to monitor the status of the product including the power supply, FPGA, CPU and the internal periodic self-detection of the on-board computer, and the historical fault information retained in the NVRAM can also be obtained, which greatly helps in on-site troubleshooting of the product.

[0005] An embodiment of the present application provides a fault status information collection interface with hot-swappable capability, the fault status information collection interface comprising: a long-short pin connector, an interface protection circuit and an RS422 transceiver connected in sequence, the RS422 transceiver being provided with an ESD protection module; the long-short pin connector comprising a long pin and a short pin, the long pin being defined as a shielded ground, and the short pin being defined as a differential signal in an RS422 bus interface; the interface protection circuit comprising a receiving end and a transmitting end, the receiving end being provided with a receiving end transient voltage protection device and a receiving end termination resistor, the transmitting end being provided with a transmitting end transient voltage protection device and a transmitting end termination resistor.

[0006] According to a specific implementation of the embodiment of the present application, the receiving end is provided with pull-up and pull-down resistors.

[0007] According to a specific implementation of the embodiment of the present application, the receiving-end transient voltage protection device is configured as a receiving-end transient voltage suppression diode, and the sending-end transient voltage protection device is configured as a sending-end transient voltage suppression diode.

[0008] According to a specific implementation method of an embodiment of the present application, the model of the transient suppression diode at the receiving end is SY5639A, the maximum operating voltage is 15V, and the breakdown voltage is 18V; the model of the transient suppression diode at the transmitting end is SY5647A, the maximum operating voltage is 33.8V, and the breakdown voltage is 39V.

[0009] According to a specific implementation of the embodiment of the present application, the receiving end termination resistor includes a receiving end positive end series resistor, a receiving end negative end series resistor and a resistor located between the receiving end positive end and the receiving end negative end.

[0010] According to a specific implementation of the embodiment of the present application, the ESD protection module is configured as a MAX13080EASD+ chip.

[0011] Beneficial effects:

[0012] The fault status information collection interface with hot-swappable capability in the embodiment of the present application uses a special electrical connector to provide signal connection to the outside. The length of the internal contact of the connector is different, and it is designed with long and short pins. In the interface definition design, all long pins are defined as shielded grounds, and the short pins of the connector can be defined as differential signals in the RS422 bus interface. When the bus interface connector on the product side is plugged into the external connector, it is ensured that all long pins are in contact first to discharge the voltage, and then the short pins used for signal transmission are in contact again to avoid the voltage difference between different devices from damaging the bus interface circuit; the differential output signal and differential output signal of the bus interface to the outside should use appropriate transient voltage suppression diodes for interface protection; the bus interface should use a transceiver device with high-level ESD protection capability to ensure that the bus interface will not be damaged by instantaneous discharge during live contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 The figure is a structural block diagram of a fault status information collection interface with hot-swap capability according to an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0016] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0017] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0018] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show the components related to the present application rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0019] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0020] The embodiment of the present application provides a hot-swappable fault status information collection interface. When an onboard computer fails, the interface can directly access the onboard computer and establish a bus data path without having to power on or off the onboard computer, thereby avoiding damage to the fault site caused by power on and off operations, facilitating the acquisition of fault site information, and facilitating later troubleshooting and reproduction of faults. Figure 1A detailed description is given, the fault status information acquisition interface includes: a long and short pin connector, an interface protection circuit and an RS422 transceiver connected in sequence, the RS422 transceiver is provided with an ESD protection module; the long and short pin connector includes a long pin and a short pin, the long pin is defined as a shielded ground, and the short pin is defined as a differential signal in the RS422 bus interface; the interface protection circuit includes a receiving end and a transmitting end, the receiving end is provided with a receiving end transient voltage protection device and a receiving end termination resistor, and the transmitting end is provided with a transmitting end transient voltage protection device and a transmitting end termination resistor.

[0021] In one embodiment, the receiving end is provided with pull-up and pull-down resistors.

[0022] In one embodiment, the receiving end transient voltage protection device is set as a receiving end transient voltage suppression diode, and the transmitting end transient voltage protection device is set as a transmitting end transient voltage suppression diode. Specifically, the receiving end transient voltage suppression diode model is SY5639A, the maximum operating voltage is 15V, and the breakdown voltage is 18V; the transmitting end transient voltage suppression diode model is SY5647A, the maximum operating voltage is 33.8V, and the breakdown voltage is 39V.

[0023] In one embodiment, the receiving end terminating resistor includes a receiving end positive end series resistor, a receiving end negative end series resistor, and a resistor located between the receiving end positive end and the receiving end negative end.

[0024] In one embodiment, the ESD protection module is configured as a MAX13080EASD+ chip.

[0025] The fault status information collection interface with hot-swappable capability in the present application is mainly composed of three parts: a specially made long and short pin connector, an interface protection circuit, and a bus transceiver with ESD protection function.

[0026] (1) Special long and short pin connector

[0027] The voltage difference of the device is the energy source of serial port hot plug. In order to achieve hot plug and avoid device damage, it is necessary to ensure that the voltage difference between the two cannot be discharged through the serial port signal line. Therefore, a customized long and short pin connector is used to ensure that the ground signals of the two are in contact first to discharge the voltage difference between the two.

[0028] The connector is a special long-short pin connector, which controls the power-on and power-off sequence of the shield ground and the signal line between the interfaces by different power-on contact times of the long and short pins, so as to realize controllable power-on timing of the hot-swap interface.

[0029] (2) Interface protection circuit

[0030] Interface protection circuit design of hot-swappable airborne computer fault information collection interface Figure 1The positive line of the receiving differential is pulled up by a 500Ω resistor, and the negative end is pulled down by a 500Ω resistor; the termination impedance of the receiving end is 120Ω (the resistor between the positive end and the negative end of the receiving end), and a 25Ω resistor is connected in series on the receiving end line; the transmitting end only needs a 50Ω resistor in series on the line. The pull-up and pull-down resistors are to ensure that the product can maintain a certain state when the external interface is floating or the voltage changes transiently, avoiding the acquisition of erroneous signals. The termination resistor and the series resistor are designed to ensure the impedance matching of the RS422 interface.

[0031] When the two devices connected by the hot-swap interface are connected to a common ground through a special long-short pin connector, the transient spikes caused by hot-swap between the two devices will be discharged through the signal line. In order to suppress the spike voltage of hot-swap, transient suppression diodes (JT) SY5639A and "G" SY5647A are used for bidirectional protection of the lines for the receiving and transmitting lines of the interface. (JT) SY5639A is used at the receiving end of the interface, with a maximum operating voltage of 15V and a breakdown voltage of 18V. "G" SY5647A is used at the transmitting end of the interface, with a maximum operating voltage of 33.8V and a breakdown voltage of 39V.

[0032] (3) Bus transceivers with ESD protection capabilities

[0033] After the signal voltage is processed by the special long and short pin connector and the interface protection circuit, it is still possible that it is higher than the voltage limit that ordinary transceivers can withstand. To solve this problem, this interface circuit uses the bus transceiver chip MAX13080EASD+ with ESD protection capability. All pins of this chip are protected by ESD, so that it can withstand up to ±15k V ESD shock. After being hit by ESD, MAX13080EASD+ can continue to work without locking or damage.

[0034] MAX13080EASD + includes a Fail-Safe function. When the receiver input pin is in a short-circuit or open-circuit state during hot-swap, or the driver transmitter is in a transmit-disabled state, the receiver output will ensure the output logic "high" level.

[0035] When using hot-swap operation with external device interface, differential interference on the transmitted data line may cause data errors. When the external device is inserted and VCC rises, the internal pull-down circuit of the chip keeps DE at a low level and RE at a high level. After completing the initialization power-on process, the pull-down circuit does not work and resets the hot-swap input terminal.

[0036] The three parts of the above-mentioned long and short pin connector, interface protection circuit, and bus transceiver with ESD protection function work together to ensure that the hot-swappable airborne computer fault information collection interface maintains stable data transmission capabilities under repeated hot-swappable working conditions.

[0037] The embodiments provided by the present invention have the following advantages:

[0038] The bus interface uses a special electrical connector to provide signal connection. The length of the internal contact of the connector is different, and it is designed with long and short pins. In the interface definition design, all long pins are defined as shielding ground, and the short pins of the connector can be defined as differential signals in the RS422 bus interface. When the bus interface connector on the product side is plugged into the external connector, ensure that all long pins are in contact first to discharge the voltage, and then the short pins used for signal transmission are in contact to avoid the voltage difference between different devices damaging the bus interface circuit;

[0039] The external differential output signal and differential output signal of the bus interface should use appropriate transient voltage suppression diodes for interface protection;

[0040] The bus interface should use a transceiver device with a high level of ESD protection to ensure that the bus interface will not be damaged by instantaneous discharge during live contact.

[0041] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A fault status information collection interface with hot-swap capability, characterized in that: The fault status information acquisition interface includes: a long and short pin connector, an interface protection circuit and an RS422 transceiver connected in sequence, and the RS422 transceiver is provided with an ESD protection module; the long and short pin connector includes a long pin and a short pin, the long pin is defined as a shielded ground, and the short pin is defined as a differential signal in the RS422 bus interface; the interface protection circuit includes a receiving end and a transmitting end, the receiving end is provided with a receiving end transient voltage protection device and a receiving end termination resistor, and the transmitting end is provided with a transmitting end transient voltage protection device and a transmitting end termination resistor.

2. The fault status information collection interface with hot-swap capability according to claim 1, characterized in that: The receiving end is provided with pull-up and pull-down resistors.

3. The fault status information collection interface with hot-swap capability according to claim 1, characterized in that: The receiving end transient voltage protection device is set as a receiving end transient voltage suppression diode, and the sending end transient voltage protection device is set as a sending end transient voltage suppression diode.

4. The fault status information collection interface with hot-swap capability according to claim 3, characterized in that: The model of the transient suppression diode at the receiving end is SY5639A, with a maximum operating voltage of 15V and a breakdown voltage of 18V; the model of the transient suppression diode at the sending end is SY5647A, with a maximum operating voltage of 33.8V and a breakdown voltage of 39V.

5. The fault status information collection interface with hot-swap capability according to claim 1, characterized in that: The receiving end terminating resistor comprises a receiving end positive end series resistor, a receiving end negative end series resistor and a resistor located between the receiving end positive end and the receiving end negative end.

6. The hot-swappable fault status information collection interface according to claim 1, characterized in that: The ESD protection module is configured as a MAX13080EASD+ chip.

Images