WO2018086458A1

WO2018086458A1 - Usb interface circuit, method and device for usb interface implementation, and computer storage medium

Info

Publication number: WO2018086458A1
Application number: PCT/CN2017/107511
Authority: WO
Inventors: 韩正渭
Original assignee: 中兴通讯股份有限公司
Priority date: 2016-11-11
Filing date: 2017-10-24
Publication date: 2018-05-17
Also published as: CN108073537A

Abstract

A universal serial bus (USB) interface circuit, a USB interface implementation method, and a device. The USB interface implementation method comprises: utilizing a difference between a VBUS voltage of an external USB device and a VBUS voltage of an external USB host to identify that a USB interface is connected to a USB host or a USB device, and processing, according to whether the USB interface is connected to a USB host or a USB device, signals on a signal line D+ and/or a signal line D-. Also provided is a computer storage medium.

Description

USB interface circuit, USB interface implementation method, device and storage medium

The present application is based on a Chinese patent application filed on Jan. 11, 2016, the filing date of

Technical field

The present invention relates to the field of communications technologies, and in particular, to a USB interface circuit, a USB interface implementation method, apparatus, and computer storage medium.

Background technique

Universal Serial Bus (USB) interface, a serial bus standard that can be connected to computer systems and external devices. It has been used for a long time in computer and communication terminal products. Among them, on the computer and customer premises equipment (CPE), the USB type (type A) type USB interface (ie, USB A type port) is very common, and it can realize power supply and communication to the device on one interface. In these applications, the USB interface acts as a host, and there are many types of connected devices, including printers, mobile hard disks, and card readers.

Many CPE products are equipped with a USB type A interface, which is a USB host interface for connecting devices such as USB flash drives and printers. However, CPE products often have another requirement, which requires a USB device interface for connecting to a PC, enabling debugging and downloading of software.

Since the traditional tpyeA type USB interface can only be used for the USB host interface, in order to connect the PC, the CPE device must add another USB device interface to connect with the PC, which will increase the product cost to a certain extent. To a certain extent, it affects the appearance of the product, that is, the existing tpyeA type USB interface cannot support the connection with the USB device and the USB host at the same time.

Summary of the invention

The embodiment of the invention provides a USB interface circuit, a USB interface implementation method, a device and a computer storage medium. It is desirable to solve the problem that the USB A port cannot simultaneously support the connection with the USB device and the USB host.

An embodiment of the present invention provides a USB interface circuit, including:

USB A port configured to connect to a USB device or USB host;

a comparison unit configured to compare the detected VBUS voltage of the USB A-type port with a preset first base voltage, and send the voltage comparison result to the processor;

The processor is configured to process the signal line D+ and/or the signal line D- according to the voltage comparison result.

Another aspect of the embodiments of the present invention provides a method for implementing a USB interface, including:

Comparing the detected VBUS voltage of the USB A port with a preset first base voltage;

The signal line D+ and/or the signal line D- are processed according to the voltage comparison result to match the USB interface circuit with the USB device or USB host to which the USB A port is connected.

Another embodiment of the present invention provides an apparatus for implementing a USB interface, including:

a comparison unit configured to compare the detected VBUS voltage of the USB A port with a preset first base voltage;

The processing unit is configured to process the signal line D+ and/or the signal line D- according to the voltage comparison result to match the USB interface circuit with the USB device or USB host connected to the USB Type A port.

A further aspect of the present invention further provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions are used in the implementation method of the USB interface provided by the foregoing technical solution.

In the embodiment of the present invention, the VBUS voltage is utilized by using an external USB device and a USB host. The difference is that the USB interface is connected to the USB host or the USB device, and the signal line D+ and/or D- is processed according to whether the USB host or the USB device is connected, so that the USB interface circuit is connected to the USB A port. The USB device or the USB host is matched, so that the same USB interface can simultaneously support the connection with the USB device and the USB host, thereby effectively solving the problem that the existing USB A-type port cannot simultaneously support the connection with the USB device and the USB host. problem.

DRAWINGS

1 is a schematic diagram of a USB interface circuit connection according to an embodiment of the present invention;

2 is a schematic diagram of another USB interface circuit connection according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of another USB interface circuit connection according to an embodiment of the present invention; FIG.

4 is a schematic flowchart of a method for implementing a USB interface according to an embodiment of the present invention;

FIG. 5 is a schematic flowchart diagram of another implementation method of a USB interface according to an embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of an apparatus for implementing a USB interface according to an embodiment of the present invention.

detailed description

The present invention provides a USB interface circuit and a method for sharing a USB interface between a USB device and a USB host, and the present invention implements the problem that the existing USB A-type port cannot support the connection with the USB device and the USB host at the same time. For example, by using the difference between the external USB device and the USB host on the VBUS voltage, it is recognized whether the USB interface is connected to the USB host or the USB device, and according to whether the USB host or the USB device is connected to the signal line D+ and/or D-. Processing, so that the USB interface circuit is matched with the USB device or USB host connected to the USB A port, so that the same USB interface can simultaneously support the connection with the USB device and the USB host, thereby effectively solving the existing USB A type. The port cannot support the connection with the USB device and the USB host at the same time. The embodiments of the present invention are further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not The invention is defined.

The embodiment of the invention provides a USB interface circuit. Referring to FIG. 1, the USB interface circuit includes:

USB A port configured to connect to a USB device or USB host;

a comparison unit configured to compare the detected VBUS voltage of the USB A port with a preset first base voltage, and send the voltage comparison result to the processor;

That is to say, in the embodiment of the present invention, by using the difference between the external USB device and the USB host on the VBUS voltage, it is recognized whether the USB interface is connected to the USB host or the USB device, and according to whether the USB host or the USB device is connected to the signal line. D+ and/or signal line D- are processed to match the USB interface circuit with the USB device or USB host connected to the USB A port, so that the same USB interface can simultaneously support the connection with the USB device and the USB host, and thus It effectively solves the problem that the existing USB A-type port cannot simultaneously support the connection with the USB device and the USB host.

The VBUS can be a power line of the USB A port, and can be configured to provide a working power by a USB device or a USB host connected by a USB A port, for example, to provide an operating voltage. A USB device connected to a USB A port can also be referred to as a USB external device.

That is, the embodiment of the present invention utilizes the low voltage requirement of the low power device to generate the VBUS voltage characteristic that not only conforms to the USB specification but also differs from the ordinary USB port, and utilizes the external connection by modifying the electrical characteristics of the USB interface. The difference between the USB device and the USB host on the VBUS voltage identifies whether the USB interface is connected to a USB host or a USB device.

It should be noted that, in the embodiment of the present invention, the USB device only transmits information and power through the USB port, and the corresponding computing work is completed by the computer, such as a USB flash drive, a USB interface printer, and the like. In this embodiment, the USB device may be connected to the processor through the USB A port. External electronic device.

The USB host is a USB interface. In addition to powering and transmitting information, the rest of the computing functions are done by itself, such as computers.

Optionally, the processor according to the embodiment of the present invention determines whether the USB A port is connected to a USB device or a USB host according to the voltage comparison result, and when the USB device is determined, the signal line is pulled through a pull-down resistor circuit. D+ and signal line D- are pulled low. When it is judged to be a USB host, the signal line D+ or D- is pulled high by a pull-up resistor circuit.

In this embodiment, the pulling down the signal line D+ and the signal line D by the pull-down resistor circuit may include: pulling down the signal line D+ and the signal line D to the low-lowed electrical signal through the pull-down resistor circuit, for example, The voltage at which the signal line D+ and the signal line D are pulled low by the pull-down resistor circuit is pulled low. The pulling up the signal line D+ or D by the pull-up resistor circuit may include: increasing the electrical signal to the signal line D+ or D through the pull-up resistor circuit, for example, boosting the signal line D+ or D through the pull-up resistor circuit To the voltage.

Optionally, in the embodiment of the present invention, when the USB device is determined, the signal line D+ or the signal line D- is connected to the ground through a pull-down resistor circuit, and when the USB host is determined, the signal line D+ is pulled through the pull-up resistor circuit. Or D-data transmission is connected to a high voltage power supply.

In this embodiment, the voltage of the high voltage power supply is higher than the voltage of the ground. The high voltage power source may be a power source having an output voltage greater than a preset voltage, for example, a power source having a voltage greater than 1.2V or 0V.

Optionally, in the embodiment of the present invention, the first base voltage is 4.4 to 4.75V, and the second base voltage is 4.75 to 5.25V.

Optionally, the circuit of the embodiment of the present invention further includes a DC power DC/DC circuit;

The DC/DC circuit is respectively connected to the processor and the USB A-type port, configured to output the first base voltage, and, under the trigger of the processor, convert the first base voltage into a second base voltage;

The processor is further configured to determine the USB A port according to the voltage comparison result When a USB device is connected, the DC/DC circuit is triggered to perform voltage conversion.

In an embodiment of the invention, the first base voltage is different from the second base voltage.

Wherein, the second base voltage is 4.75 to 5.25V.

For example, the embodiment of the present invention is a DC/DC circuit capable of outputting a first base voltage (4.4 to 4.75 V, that is, a voltage of a USB device) and a second base voltage (4.75 to 5.25 V, that is, a voltage of a USB host), in processing When it is determined that the USB A port is connected to a USB device, the DC/DC circuit can be switched to the voltage of the USB host to match the connected USB device.

Optionally, the circuit of the present invention further includes: a current limiting anti-backflow circuit; the current limiting anti-backflow circuit connecting the DC/DC circuit to the USB A port.

For example, the lowest voltage of the USB protocol to the host's VBUS output, the specific requirements are high power port minimum 4.75V to 5.25V, low power port is 4.4V to 5.25V. The USB protocol also stipulates that the device is considered to be a low-power device by default before the enumeration is recognized as a high-power device. The required current does not exceed 100 mA, and the supported operating voltage can be as low as 4.4V. Therefore, the embodiment of the present invention sets a special USB type A USB interface, and the initial voltage of the VBUS is between 4.4V and 4.75V. When a USB device is plugged into this interface, since the USB device defaults to a low-power device before the enumeration succeeds, this does not affect the identification and enumeration of the USB device. After identifying that the USB device is plugged in, the interface can internally switch the VBUS voltage to above 4.75V to meet the power supply requirements of the high-power device.

If the above interface is connected to a standard USB host interface, the host interface will output a voltage higher than 4.75V to reach the type A USB interface, and raise the VBUS voltage on the interface to 4.75V or higher. After the higher VBUS voltage is recognized by the processor, it can be judged that the opposite end is not a USB device, but a USB host, and then the pull-up resistor can be connected to the D+/D- and the protocol stack can be switched to allow the device to Enter the USB device mode to communicate with the external host.

The USB type A type USB interface can be as shown in Fig. 2. In Fig. 2, R1 = R2 = 15k and R3 = 1.5k. After power-on, the USB interface defaults to the host mode. At this time, the DC/DC outputs 4.5V voltage, and the switch control signal turns on the first resistor R1 and the second resistor R2, and disconnects the third resistor R3. The following description is based on the difference in the identity of the peer end of the USB interface.

When the USB device is inserted, the 4.5V power supply on the USB interface VBUS of the embodiment of the present invention supplies power to the inserted USB device through the type A type USB interface, and after the USB device is powered on, the D+ or D- is pulled according to the protocol. The level of the processor inside the interface of the present invention, after identifying the level signal, sends a voltage control signal to switch the output voltage to 5.0V, and the subsequent workflow is exactly the same as the standard USB specification. Since the VBUS voltage has been switched to the standard 5.0V voltage, the USB protocol can be followed, regardless of whether a low-power device or a high-power device is inserted.

When the user unplugs the USB device, it can be detected by the host according to the USB communication specification. At this time, the VBUS voltage is re-switched to 4.5V by the voltage control signal, and the initial state is returned.

When plugged into a normal USB host interface, the two VBUS power supplies are shorted together because both sides are USB hosts. Since the VBUS default voltage (4.5V) of the USB interface of the present invention is lower than the VBUS voltage (4.75 to 5.25V) on the common interface, the VBUS current of the external USB host will flow into the device, and the VBUS on the USB interface of the device is raised. Voltage, (due to the internal anti-current circuit of the device, it will not damage DC/DC). Inside the device, the comparison portion can detect the rise of the voltage, thereby judging that the USB interface has been connected to the external USB host.

After judging that there is an external host connection, the device switches the internal protocol stack into the USB device mode, and through the switch control signal, disconnects the resistors R1 and R2 from the USB signal line, and turns R3 on D+. Since the R3 is turned on, the D+ signal is pulled up, and the externally inserted host recognizes the signal, determines that a USB full-speed device is inserted, and then performs device identification and enumeration according to the USB specification. After the enumeration is successful, the inserted host and the device exchange data through the USB interface to complete the required services. After the user may unplug this USB host, the device can check The VBUS voltage is measured to reduce the switching protocol stack to the host state. At this time, the VBUS voltage on the interface is powered by the internal DC/DC, and the output is 4.5V, returning to the initial state.

When the USB HUB is inserted, that is, the standard USB HUB uplink port is inserted, the USB interface identification and enumeration process of the present invention is similar to the insertion of the USB device, and the 4.5V power supply on the local VBUS supplies power to the HUB through the type A interface. After power-on, the USB HUB will raise the D+ level. After the processor recognizes the level signal, it sends a voltage control signal to switch the output VBUS voltage to 5.0V. Other aspects are no different from the standard agreement.

Optionally, the comparing portion of the embodiment of the present invention may be specifically configured as a comparator or an analog-to-digital converter (ADC) to implement a function of comparing differences on the VBUS voltage.

2 is a schematic diagram of another USB interface circuit connection according to an embodiment of the present invention. As shown in FIG. 2, the non-inverting input terminal of the comparator of the embodiment of the present invention is connected to a USB A-type port, and the reverse input terminal and the DC/DC circuit are connected. Connecting, the output end is connected to the processor, for comparing a VBUS voltage of the USB A-type port with a first base voltage of the DC/DC circuit, and transmitting a voltage comparison result to the processor; the processor According to the voltage comparison result, it is judged whether it is a USB host or a USB device, and when it is determined that it is a USB host, the signal line D+ or the signal line D- is pulled up by the pull-up resistor circuit, and when the USB device is determined, the signal is pulled through the pull-down resistor circuit. Line D+ and signal line D- are pulled low and the first base voltage of the DC/DC circuit is converted to a second base voltage.

Optionally, at the beginning, the initial voltage of the VBUS of the USB interface of the present invention is between 4.4V and 4.75V. When a USB device is inserted into the interface, the comparator recognizes the VBUS voltage and sends the voltage comparison result. To the processor, the processor determines, according to the voltage comparison result, that the interface is inserted into the USB device, triggers the DC/DC circuit to perform voltage conversion, raises the VBUS voltage to above 4.75V, and satisfies the power supply requirement of the high-power device, and at D+/ Connect the pull-up resistor on the D- and switch the protocol stack to let the device enter the USB device mode to communicate with the external host. That is, after power-on, the USB interface defaults to the host mode. At this time, the DC/DC outputs 5V voltage, and the switch control signal turns on R1 and R2, disconnect R3.

After the user plugs in the normal USB host interface, the two VBUS power supplies are shorted together because both sides are USB hosts. The default VBUS voltage of this interface (4.5V) is lower than the VBUS voltage (4.75 to 5.25V) on the common interface, so the VBUS current of the external USB host will flow into the device and raise the VBUS voltage on the USB interface of the device. The device contains an anti-current back-up circuit that does not damage the DC/DC). Inside the device, the rise of the voltage can be detected by the comparator, thereby judging that the USB interface has been connected to an external USB host. After the processor determines that there is an external host connection, the internal protocol stack is switched to enter the USB device mode, and the connection between the resistors R1 and R2 and the USB signal line is cut off by the switch control signal, and R3 is connected to D+. Since the R3 is turned on, the D+ signal is pulled up, and the externally inserted host recognizes the signal, determines that a USB full-speed device is inserted, and then performs device identification and enumeration according to the USB specification. After the enumeration is successful, the inserted host and the device exchange data through the USB interface to complete the required services.

After the user may unplug the USB host, the device can detect the decrease of the VBUS voltage, thereby switching the protocol stack to the host state. At this time, the VBUS voltage on the interface is powered by the internal DC/DC, and the output is 4.5V, and the return is performed. To the initial state.

3 is a schematic diagram of another USB interface circuit connection according to an embodiment of the present invention. With respect to FIG. 2, FIG. 3 of the present invention performs all functions of the comparator of FIG. 2 through an analog-to-digital converter ADC, and optionally, the present invention. The analog-to-digital converter ADC of the embodiment is respectively connected to the USB A port and the processor, and compares the VBUS voltage of the USB A port with the first base voltage of the DC/DC circuit, and sends the voltage comparison result to The processor determines whether the USB host or the USB device is based on the voltage comparison result, and when the USB host is determined, the signal line D+ or D- is connected to the high voltage through the pull-up resistor circuit, and the determination is USB. In the case of the device, the signal lines D+ and D- are pulled high by a pull-down resistor circuit, and the first base voltage of the DC/DC circuit is converted to a second base voltage.

Alternatively, those skilled in the art can understand according to the example of the comparator of the present invention, and details are not described herein again.

In order to better illustrate the interface of the present invention, the present invention will be explained and illustrated by way of several specific application examples:

The application of the USB interface circuit of the invention on the CPE: On many CPE devices that handle wireless, wired and fiber access, it is often necessary to provide a USB A-type interface to the user, and an external USB device such as a USB flash drive and a printer. In addition to this, you need a USB interface, working in USB device mode, after connecting to the PC, for debugging and downloading upgrades. On this type of device, we can use the USB A-type interface of the present invention, and only need one interface to realize the above two functions at the same time, which saves cost and volume, especially when the number of USB ports of the CPE internal processor is limited. When you can save the relevant circuit of the USB interface expansion.

The type A USB interface defaults to the host mode. When the user inserts the USB device, the interface supplies power, identifies, and enumerates the inserted user USB device through VBUS to complete the required service.

When the after-sales or R & D personnel need to debug or download, you can directly connect the interface to the type A USB interface of the PC. At this time, because the default VBUS voltage of the PC is higher than that of the CPE device, the CPE will switch to the USB device mode according to the method described above, and implement the function of debugging or downloading and upgrading.

Of course, the special features of this interface can also be opened to users. After the user connects to the PC, the CPE device also works in the USB device mode. The user can directly access the Internet through the USB cable or access the stored content inside the CPE.

The application of the USB interface circuit of the embodiment of the invention on a PC and a tablet computer: a USB type A USB interface is widely used on the current PC, and only the host mode is supported. If the technology of the present invention can be used to transform it into an OTG interface, high-speed interconnection between two PCs without using other switching devices can be realized, and the storage of another PC can be accessed at a high speed on one PC. Storage space, practical. Since this interconnect does not require an IP address, it is faster and more convenient than a network cable.

In some embodiments, it is possible to indicate whether a type A USB interface supports the OTG (On-The-Go) function by means of color or characters. If the OTG is supported, the interface can be directly connected to the host interface of other devices. In this case, the local device will be regarded as a USB device externally connected to the USB host interface of the other device. If the type A type USB interface described in the present invention is interconnected, since the VBUS voltages on both sides are lower than the threshold of 4.75V after the interconnection, the insertion of the other party cannot be recognized, so that the host mode is maintained. The insertion of the other party could not be recognized. But this will not cause damage to the interface, compared to the traditional type A USB interface, is also an improvement. The traditional type A USB host interface is interconnected, which may cause damage to the interface.

The application of the USB interface circuit of the embodiment of the present invention on a tablet computer: since a large number of existing USB devices are type A type plugs, such as a U disk, a U key, etc., the type A type USB interface is also retained on the tablet computer. Necessary. In fact, a significant portion of the tablets currently on sale retain a type A USB interface, such as Microsoft's SURFACE series. However, the tablet computer has high requirements for portability. If the interface supports the OTG mode at the same time, the two functions of connecting the computer and connecting the peripheral device can be realized by one interface, which is very advantageous for controlling the size.

Generally, in the embodiment of the present invention, by using the difference between the external USB device and the USB host on the VBUS voltage, it is recognized whether the USB interface is connected to the USB host or the USB device, and according to whether the USB host or the USB device is connected to the signal line. D+ and/or D- are processed to match the USB interface circuit with the USB device or USB host connected to the USB A port, so that the same USB interface can simultaneously support the connection with the USB device and the USB host, thereby effectively solving the problem. The existing USB A-type port cannot support the connection with the USB device and the USB host at the same time.

An embodiment of the present invention provides a method for implementing a USB interface. Referring to FIG. 4, the method package is provided. include:

S401. Compare the detected VBUS voltage of the USB A port with a preset first base voltage;

S402. Process the signal line D+ and/or the signal line D- according to the voltage comparison result, so that the USB interface circuit matches the USB device or the USB host connected to the USB Type A port.

The invention recognizes whether the USB interface is connected to the USB host or the USB device by using the difference between the external USB device and the USB host on the VBUS voltage, and according to whether the USB host or the USB device is connected to the signal line D+ and/or D- Processing to match the USB interface circuit to the USB device or USB host connected to the USB A port, so that the same USB interface can simultaneously support the connection with the USB device and the USB host, thereby effectively solving the existing USB A. The port cannot support the connection to the USB device and the USB host at the same time.

In the embodiment, the step S402 processes the signal line D+ and/or the signal line D- according to the voltage comparison result, for example, adjusting the voltage value on the signal line D+ and/or the signal line D-, so that the D of the USB interface The voltage on the signal line matches the voltage required by the currently connected device. The device here can be an external USB device, or a USB host. The electrical signal herein is not limited to a voltage, and in some embodiments, may be a current. The D signal line here includes: a signal line D+ and a signal line D-.

For example, the step S402 of the present invention specifically includes: determining, according to the voltage comparison result, whether the USB A port is connected to a USB device or a USB host, and when determining that the USB device is a USB device, the signal line D+ is pulled through a pull-down resistor circuit. And the signal line D- is pulled low, and when it is judged to be the USB host, the signal line D+ or the signal line D- is pulled up by the pull-up resistor circuit.

Optionally, the present invention connects the signal lines D+ and D- to the ground through a pull-down resistor circuit when determining that it is a USB device, and connects the signal line D+ or D- with a high voltage through the pull-up resistor circuit when determining that the USB host is a USB host. Power connection.

Optionally, the method of the embodiment of the present invention further includes: outputting the first base voltage by using a DC/DC circuit, and determining, by the voltage comparison result, that the USB A port is connected to a USB device. In standby mode, the output of the DC/DC circuit converts the first base voltage into a second base voltage; wherein the second base voltage is 4.75 to 5.25V.

Optionally, the embodiment of the present invention connects the DC/DC circuit to the processor and the USB A port, and the DC/DC circuit outputs the first base voltage, and when the processor triggers, the first Converting a base voltage to a second base voltage; the processor triggering the DC/DC circuit to perform voltage conversion when determining that the USB A port is connected to the USB device according to the voltage comparison result.

FIG. 5 is a schematic flowchart of another method for sharing a USB interface between a USB device and a USB host according to an embodiment of the present invention. As shown in FIG. 5, the method includes:

S501, USB power on;

S502, VBUS default output 4.5V, turn on the pull-down resistors R1 and R2;

S503, judging the D+/D-level, having a high level to enter S504, otherwise entering S508; the high level may be a level higher than a preset reference level.

S504, switching VBUS voltage is 5V; switching VBUS voltage to 5V can be: switching the voltage on VBUS to 5V;

S505, working as a USB host to identify and enumerate peripherals;

S506. Transmitting data through a USB interface;

S507, unplug the USB cable, the USB communication is terminated, and return to S502;

S508, detecting a VBUS voltage;

S509, determining whether the VBUS voltage is higher than 4.5V, and if so, proceeding to the next step, otherwise proceeding to S502;

S510, having host access, disconnecting resistors R1 and R2, and turning on R3;

S511, working as a USB peripheral, cooperate with the host to complete the identification and enumeration of peripherals;

S512, the device and the inserted host transmit data through the USB interface;

S513. Unplug the USB cable, the USB communication is terminated, and the process returns to S502.

The related content in the embodiments of the present invention can be understood by referring to the circuit embodiment and the device implementation part, and details are not described herein again.

An embodiment of the present invention provides an apparatus for implementing a USB interface. Referring to FIG. 6, the apparatus includes:

a comparison unit configured to compare the detected VBUS voltage of the USB A-type port with a preset first base voltage; the comparison unit may include: a comparator or a comparison circuit having a comparison function

The processing unit is configured to process the signal line D+ and/or the signal line D- according to the voltage comparison result to match the USB interface circuit with the USB device or USB host connected to the USB Type A port. The processing unit can include a processor or processing circuitry. The processor can include a central processing unit, a microprocessor, a digital signal processor, an application processor, a programmable array, an application processor, or an application specific integrated circuit.

In the embodiment of the present invention, by using the difference between the external USB device and the USB host on the VBUS voltage, it is recognized whether the USB interface is connected to the USB host or the USB device, and according to whether the USB host or the USB device is connected to the signal line D+ and/or D- is processed to match the USB interface circuit with the USB device or USB host connected to the USB A port, so that the same USB interface can simultaneously support the connection with the USB device and the USB host, thereby effectively solving the existing The USB Type A port cannot support the connection to the USB device and the USB host at the same time.

Optionally, the processing unit of the embodiment of the present invention is further configured to determine, according to the voltage comparison result, whether the USB A port is connected to a USB device or a USB host, and when determining that the USB device is a pull-down resistor The circuit pulls the signal line D+ and the signal line D- low, in the judgment is When the USB host is used, the signal line D+ or the signal line D- is pulled up by the pull-up resistor circuit.

Optionally, the processing unit of the embodiment of the present invention is further configured to: when determining that the USB device is connected to the USB A-type interface, connect the signal lines D+ and D- to the ground through a pull-down resistor circuit, and determine the USB A type. When the interface is connected to a USB host, the signal line D+ or D- is connected to the high voltage power supply through a pull-up resistor circuit.

Optionally, the device according to the embodiment of the present invention further includes: a DC power supply unit; the DC power supply unit configured to output the first base voltage, and when the voltage comparison result determines that the USB A port is connected When it is a USB device, the output first base voltage is converted into a second base voltage.

Optionally, the embodiment of the present invention connects the DC/DC circuit to the processor and the USB A port, and the DC/DC circuit outputs the first base voltage, and when the processor triggers, the first The base voltage is converted into a second base voltage; the processor is further configured to trigger the DC/DC circuit to perform voltage conversion when determining that the USB A port is connected to the USB device according to the voltage comparison result.

For example, the embodiment of the present invention is a DC/DC circuit capable of outputting a first base voltage (4.4 to 4.75 V) and a second base voltage (4.75 to 5.25 V), when the processor determines that the USB A port is connected to a USB device. The DC/DC circuit can be switched to the voltage of the USB host to match the connected USB device.

The related content in the embodiments of the present invention can be understood by referring to the circuit embodiment and the method implementation part, and details are not described herein again.

In the embodiment of the present invention, by using the difference between the external USB device and the USB host on the VBUS voltage, it is recognized whether the USB interface is connected to the USB host or the USB device, and according to whether the USB host or the USB device is connected to the signal line D+ and / Or D- processing to match the USB interface circuit with the USB device or USB host connected to the USB A port, so that the same USB interface can simultaneously support the connection with the USB device and the USB host, thereby effectively solving the existing of The USB Type A port cannot support the connection to the USB device and the USB host at the same time.

The embodiment of the present invention further provides a computer storage medium, where the computer executable medium stores computer executable instructions, and the computer executable instructions are executed by a processor or the like, and the foregoing one or more embodiments may be implemented. The implementation of the provided USB interface.

The computer storage medium provided by the embodiment of the invention includes: a mobile storage device, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and the like, which can store program codes. Medium. Optionally, the computer storage medium can be a non-transitory storage medium. The non-transitory storage medium herein may also be referred to as a non-volatile storage medium.

While the preferred embodiments of the present invention have been disclosed for purposes of illustration, those skilled in the art will recognize that various modifications, additions and substitutions are possible, and the scope of the invention should not be limited to the embodiments described above.

Industrial applicability

In the embodiment of the present invention, the VBUS voltage of the USB A port is detected, and the comparison result is compared with the first base voltage to obtain a comparison result; and then the processor determines, according to the comparison result, that the current connection is to the USB. Whether the A-port connected device is a USB peripheral or a USB host, so that the signal line D+ and/or the signal line D- can be output to the currently connected device by adjusting the electrical signal on the signal line D+ and/or the signal line D-. The compatible electric signal enables the USB A-type port to be adapted to both the USB peripheral device and the USB host, thereby solving the problem of the limitation of the use of the USB A-type port, and expanding the USB A-type port. Connectable devices with positive industrial effects. And by detecting the voltage and comparison of the VBUS, and adjusting the electrical signal on the signal line D+ and/or the signal line D-, it has the characteristics of simple implementation, wide use in the industry, and thus industrially achievable. .

Claims

A USB interface circuit comprising:

USB A port configured to connect to a USB device or USB host;

a comparison unit configured to compare the detected VBUS voltage of the USB A port with a preset first base voltage, and send the voltage comparison result to the processor;

The processor is configured to process the signal line D+ and/or the signal line D- according to the voltage comparison result.
The USB interface circuit according to claim 1, wherein

The processor is further configured to determine, according to the voltage comparison result, whether the USB A-type port is connected to a USB device or a USB host, and when determining that the USB device is a USB device, the signal line D+ and the signal line D are connected through a pull-down resistor circuit. - Pull low, when the USB host is judged, the signal line D+ or the signal line D- is pulled up by the pull-up resistor circuit.
The USB interface circuit according to claim 2, wherein the USB interface circuit further comprises: a DC power supply DC/DC circuit;

The DC/DC circuit is respectively connected to the processor and the USB A port, configured to output the first base voltage, and after the processor is triggered, convert the first base voltage into a second Base voltage

The processor is further configured to trigger the DC/DC circuit to perform voltage conversion when it is determined that the USB A port is connected to the USB device according to the voltage comparison result.
The USB interface circuit according to claim 3, wherein

The first base voltage is 4.4 to 4.75 V, and the second base voltage is 4.75 to 5.25 V.
The USB interface circuit of claim 3, wherein the USB interface circuit further comprises: a current limiting anti-backflow circuit;

The current limiting anti-backflow circuit connects the DC/DC circuit to a USB Type A port.
The USB interface circuit according to claim 3, wherein the comparing portion comprises: a comparator;

The non-inverting input of the comparator is connected to the USB A port, the inverting input is connected to the DC/DC circuit, and the output is connected to the processor, and configured to connect the VBUS voltage of the USB A port with the DC/ Comparing the first base voltage of the DC circuit, and transmitting the voltage comparison result to the processor;

The processor is further configured to determine whether the USB host or the USB device is based on the voltage comparison result, and when the USB host is determined, the signal line D+ or the signal line D- is pulled up by the pull-up resistor circuit, and the USB device is determined to be At this time, the signal line D+ and the signal line D- are pulled low by a pull-down resistor circuit, and the first base voltage of the DC/DC circuit is converted into a second base voltage.
The USB interface circuit according to claim 3, wherein the comparing portion comprises: an analog to digital converter;

The analog-to-digital converter ADC is respectively connected to the USB A-type port and the processor, and is configured to compare the VBUS voltage of the USB A-type port with the first basic voltage of the DC/DC circuit, and send the voltage comparison result to the Processor

The processor is further configured to determine whether the USB host or the USB device is based on the voltage comparison result, and when the USB host is determined, the signal line D+ or the signal line D- is pulled up by the pull-up resistor circuit, and the USB device is determined to be At this time, the signal line D+ and the signal line D- are pulled low by a pull-down resistor circuit, and the first base voltage of the DC/DC circuit is converted into a second base voltage.
A method for implementing a USB interface includes:

Comparing the detected VBUS voltage of the USB A port with a preset first base voltage;

The signal line D+ and/or the signal line D- are processed according to the voltage comparison result, and the signal line D is matched with a USB device or a USB host that connects the USB interface circuit to the USB Type A port.
The method of claim 8 wherein said comparing according to said voltage comparison result The signal line D+ and/or the signal line D- are processed, including:

Determining, according to the voltage comparison result, whether the USB A port is connected to a USB device or a USB host, and when determining that the USB device is a USB device, pulling down the signal line D+ and the signal line D- through a pull-down resistor circuit, determining that the USB is At the time of the host, the signal line D+ or the signal line D- is pulled high by the pull-up resistor circuit.
The method according to claim 9, wherein the method further comprises: outputting the first base voltage through a DC/DC circuit, and when the voltage comparison result determines that the USB A port is connected to a USB device, The output of the DC/DC circuit converts the first base voltage into a second base voltage.
The method of claim 9 wherein

The first base voltage is 4.4 to 4.75 V, and the second base voltage is 4.75 to 5.25 V.
A device for implementing a USB interface, comprising:

a comparison unit configured to compare the detected VBUS voltage of the USB A port with a preset first base voltage;

The processing unit is configured to process the signal line D+ and/or the signal line D- according to the voltage comparison result to match the USB interface circuit with the USB device or USB host connected to the USB Type A port.
The device according to claim 12, wherein

The processing unit is further configured to determine, according to the voltage comparison result, whether the USB A port is connected to a USB device or a USB host, and when determining that the device is a USB device, the signal line D+ and the signal line D are connected through a pull-down resistor circuit. - Pull low, when the USB host is judged, the signal line D+ or the signal line D- is pulled up by the pull-up resistor circuit.
The device according to claim 13, wherein the implementation device of the USB interface further comprises: a DC power supply unit;

The DC power supply unit is configured to output the first base voltage when the voltage is compared As a result, it is judged that when the USB A port is connected to the USB device, the output first base voltage is converted into the second base voltage.
The device according to claim 14, wherein

The first base voltage is 4.4 to 4.75 V, and the second base voltage is 4.75 to 5.25 V.
A computer storage medium having stored therein computer executable instructions for performing the method of implementing the USB interface provided by any one of claims 8 to 11.