CN109660894B

CN109660894B - Terminal peripheral and audio signal transmission method

Info

Publication number: CN109660894B
Application number: CN201710948957.2A
Authority: CN
Inventors: 蒋益相; 柴峻; 黄宗伟
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2017-10-12
Filing date: 2017-10-12
Publication date: 2020-09-15
Anticipated expiration: 2037-10-12
Also published as: CN109660894A; WO2019072244A1

Abstract

The embodiment of the invention provides a terminal peripheral and an audio signal transmission method, wherein the terminal peripheral comprises: the device comprises a USB plug, an audio module and an equipment control module; the device control module is used for controlling a transmission channel adopted for signal transmission between the USB plug and the audio module, wherein the channel comprises a first transmission channel and a second transmission channel, the first transmission channel comprises a USB audio UAC audio channel, and the second transmission channel comprises a low-power consumption inter-chip serial media SLIM bus audio channel.

Description

Terminal peripheral and audio signal transmission method

Technical Field

The invention relates to the field of electronic equipment, in particular to a terminal peripheral and an audio signal transmission method.

Background

At present, the USB Type-C earphone mainly has two types of realization structures: UAC digital headphones and analog-to-digital hybrid headphones.

UAC digital earphone:

the UAC earphone comprises four parts: USB to I2S bridge module, audio CODEC module, drive-by-wire, earphone and microphone body. Following the USB Audio Device Class Specification.

The UAC is a USB Audio Class, and a universal data interface such as a USB, and can have various modes for realizing digital Audio data transmission. Different developers can define parameters such as any control mode, transmission mode, audio format and the like according to own preference and requirements.

USB is well suited as a PC-based audio (including voice and music) transport protocol, and PC-based telephony systems have been an important consideration and driving force for the development of USB interfaces from the beginning. On the other hand, the USB interface has a bandwidth much higher than the audio requirement, and can transmit audio data of extremely high quality (high sampling rate, high coding rate, multi-channel). Therefore, audio functions such as telephone, music playback, recording, etc. can be easily implemented on the USB interface.

The Google Android 5.0 system has also supported USB DAC devices and digital headsets. Google android6.0 has added support for USB VOICE calls.

The USB Type C earphone is realized in a mixed mode. The envisaged working mode is: during voice communication, a USBType-C passive analog earphone Adapter framework is used to follow the Audio Adapter Access model specification; the UAC structure is adopted when the music is played, and the USB Audio Device Class Specification is followed.

However, the above-described technical solutions have the following problems:

1) the call delay is large, and the UAC earphone can not meet the delay requirement of voice call under the cellular mobile network.

2) The analog audio signal has poor anti-jamming capability, and the audio signal of the analog-digital mixed earphone is easily interfered when the analog-digital mixed earphone works in an analog mode, so that the conversation quality and the music effect are influenced.

3) The existing USB Type-C earphone structure has large power consumption, a USB-I2S bridge I2S OVER USB mode is adopted, and an audio signal flows away through a USB physical channel. The power consumption of the USB channel is large, and an application processor on the host side cannot sleep when the USB channel is used, so that the power consumption overhead is increased.

In order to solve the above problems, a scheme of using a low-power-consumption low-delay data bus to directly pass through a USB interface to connect with an audio module is provided in the related art, however, the problem of poor signal interference resistance due to compatibility with an existing earphone architecture is not considered, and the application scenarios of the product are limited.

Disclosure of Invention

The embodiment of the invention provides a terminal peripheral and a transmission method of an audio signal, which at least solve the problem that a low-power-consumption low-delay solution in the related technology cannot simultaneously have signal anti-interference performance.

According to an embodiment of the present invention, there is provided a terminal peripheral including: the device comprises a Universal Serial Bus (USB) plug, an audio module and an equipment control module; the device control module is used for controlling a transmission channel adopted for signal transmission between the USB plug and the audio module, wherein the channel comprises a first transmission channel and a second transmission channel, the first transmission channel comprises a USB audio UAC audio channel, and the second transmission channel comprises a serial media SLIM bus audio channel between low-power consumption chips.

According to another embodiment of the present invention, there is provided a transmission method of an audio signal, including: after the terminal peripheral is connected with the terminal, the terminal peripheral determines a channel type adopted by a USB plug for signal transmission with an audio module, wherein the channel type comprises a first transmission channel and a second transmission channel which are arranged between the USB plug and the audio module, the first transmission channel comprises a USB audio UAC audio channel, and the second transmission channel comprises a second transmission channel which comprises a low-power inter-chip serial media SLIM bus audio channel; and the terminal peripheral equipment performs signal transmission between the USB plug and the audio module according to the determined channel type.

According to an embodiment of the present invention, there is provided a terminal peripheral including: the device comprises a Universal Serial Bus (USB) plug, an audio module and a device control module, wherein the device control module is connected with the USB plug and the audio module; the terminal peripheral further includes: the first conversion bridge module is connected with the USB plug and the equipment control module and is used for converting the audio signals received from the USB plug from the USB format into the I2S format; and the second conversion bridge module is connected with the USB plug and the device control module and is used for converting the audio signals received from the USB plug from the SLIMbus format into the I2S format.

According to the invention, the channel type between the USB plug and the audio module can be controlled through the equipment control module, so that the compatibility of the architecture of the new terminal peripheral and the existing architecture of the terminal peripheral can be realized, the problem that the low-power-consumption low-delay solution cannot simultaneously have signal anti-interference performance can be solved, and the application scene of the product is expanded.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

fig. 1 is a block diagram of a configuration of a terminal peripheral according to an embodiment of the present invention;

FIG. 2 is a block diagram of an alternative terminal peripheral according to an embodiment of the present invention;

fig. 3 is a block diagram of a digital dual mode audio signal transmission system according to an embodiment of the present invention;

FIG. 4a is a schematic diagram of the audio channel and USB channel setup when the headset plug is inserted in the forward direction according to the embodiment of the present invention;

fig. 4b shows the corresponding relationship between the socket and the plug pin when the earphone plug is inserted in the forward direction according to the embodiment of the present invention;

FIG. 5a is a schematic diagram of the audio channel and USB channel set up with a reverse insertion of an earphone plug according to an alternative embodiment of the present invention;

fig. 5b shows the corresponding relationship between the socket and the plug pin when the earphone plug is inserted reversely according to the alternative embodiment of the present invention;

fig. 6a is a circuit schematic of an alternative CC module according to an alternative embodiment of the invention;

FIG. 6b is a circuit schematic of another alternative CC module in accordance with an alternative embodiment of the invention;

FIG. 7 is a flowchart of the interaction between a SLIM BUS Over USB Type-C host and a peripheral device, in accordance with an alternative embodiment of the present invention;

FIG. 8 is a flow diagram of dual mode peripheral UAC mode operation when a host supports the UAC architecture in accordance with an alternative embodiment of the present invention;

FIG. 9 is a schematic diagram of a dual mode audio signal transmission system architecture in accordance with an alternative embodiment of the present invention;

fig. 10 is a schematic diagram of a dual mode headset circuit in accordance with an alternative embodiment of the present invention;

FIG. 11 is a flow chart illustrating interaction between a host and a headset according to an alternative embodiment of the present invention;

fig. 12 is a flowchart of the dual mode earpiece UAC mode operation according to an alternative embodiment of the present invention;

fig. 13 is a flowchart of a transmission method of an audio signal according to an alternative embodiment of the present invention.

Detailed Description

The invention will be described in detail hereinafter with reference to the accompanying drawings in conjunction with embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

The UAC headset and the analog-digital hybrid headset in the related art have the problems of long call delay, poor anti-interference capability, large power consumption and the like, and therefore, to solve the problems, the adopted scheme must have the following characteristics: the mobile communication has low time delay, pure digital mode and low power consumption.

On the current mainstream terminal platform, the SLIMbus digital audio bus perfectly realizes the transmission of control signals, audio signals and data signals between the SOC (including an application processor AP, a baseband processor DBB and the like) and the audio CODEC by using two wires. And has a series of characteristics for solving the inherent problems of the UAC architecture earphone: low time delay, pure digital and low power consumption. The method is a very simple scheme for signal transmission between chips.

To solve the above problem, in this embodiment, the SLIMbus is directly pulled out from the terminal and used as a bus for transferring signals between the terminal and the headset, so as to implement a headset scheme of SLIMbus Over (pass through) USB Type-C? And has been demonstrated to be feasible.

The english full name of SLIMbus is: serial Low-power Inter-chip Media Bus, English definition is: the Serial Low-power Inter-chip Media Bus (SLIMbus)^SM) The serial media bus SLIMbus between low power consumption chips is a standard interface between the baseband or application processor and the peripheral components in the mobile terminal.

In addition to low power consumption and meeting the requirement of call delay, the SLIMbus can be hung with a plurality of peripheral devices like an I2C bus. Thus, an audio CODEC can be hung in the host and an audio CODEC can be hung outside the host.

Simultaneously, as a USB Type-C earphone, the basic attribute requirements of the USB earphone must be met: and hot plug and USB Type-C interface crossing are supported.

That SLIMbus supports how hot swappable? The answer is affirmative. SLIMbus is not designed to increase hot-swap capacity, but rather is intended to complete communications within a single client terminal, such as a mobile phone. However, the SLIMbus device allows dynamic "drop" and "re-access" of the bus according to system usage requirements arising from the appropriate protocol in the SLIMbus specification. This can just satisfy the hot plug requirement of USBType-C earphone

That SLIMbus can cross USB Type-C port? The answer is affirmative. SLIMbus is a serial bus that has only two wires: the clock line CLK and the DATA line DATA, the control signal, the audio signal and the line control signal are transmitted by using the two lines, and the USB Type-C interface is easy to pass through in a pin multiplexing or port expansion mode.

Therefore, the earphone architecture, namely the earphone of the SLIMbus Over USB Type-C, can be designed based on the SLIMbus.

In addition, the conventional UAC headset also has a huge user group, and in consideration of the application universality, the embodiment provides a dual-mode headset which supports both the SLIMbus Over USB Type-C architecture and the UAC architecture.

In addition, the SLIMbus bus and the SoundWire bus in the dual mode are both in a dual bus form, one is a clock line and the other is a serial data line, and are compatible in electrical characteristics. Both the SLIMbus bus and SoundWire are MIPI protocol standards.

Based on the design concept, the embodiment of the application provides a solution for the terminal peripheral, and the detailed description is provided in the following embodiments.

Example 1

The present embodiment provides a terminal peripheral, as shown in fig. 1, the terminal peripheral: a Universal Serial Bus (USB) plug 12, an audio module 14 and an equipment control module 10; wherein the content of the first and second substances,

the device control module 10 is configured to control a transmission channel used for signal transmission between the USB plug 12 and the audio module 14, where the channel includes a first transmission channel and a second transmission channel, the first transmission channel includes a USB audio UAC audio channel, and the second transmission channel includes a low-power inter-chip serial media SLIM bus audio channel.

Optionally, the UAC audio channel is configured to convert an audio signal received through the USB plug 12 from a USB format to an inter-IC audio I2S format; and the SLIM bus audio channel is used for converting the audio signals received by the USB plug from the low-power consumption inter-chip serial media SLIM bus format into the I2S format.

Optionally, as shown in fig. 2, the apparatus further includes: a first conversion bridge module 16 disposed on the first transmission channel for converting the audio signal received from the USB plug from the USB format into the I2S format

Optionally, the first bridge module 16 is built into the equipment control module 10.

Optionally, as shown in fig. 2, the apparatus further includes: a second conversion bridge module 18, disposed on the second transmission channel, for converting the audio signal received from the USB plug from the SLIMbus format to the I2S format. Optionally, the second translation bridge module includes a HUB.

Optionally, the second conversion bridge module 18 is a programmable circuit module, and is configured to obtain a firmware upgrade program from the device control module 10, where the firmware upgrade program is configured to convert the second conversion bridge module from a first function to a second function, where the first function is to convert an audio signal from a SLIMbus format to an I2S format, and the second function is to convert an audio signal received from the USB plug from a Soundwire bus format to an I2S format.

Optionally, the USB plug includes one of: USB Type-C plug, Micro USB plug.

For better understanding of the above embodiments, the following description will be made taking USB Type-C headphones as an example.

In order to solve the problems (call delay, power consumption and anti-interference) of the UAC digital earphone and the analog-digital mixed earphone, the invention provides a SLIMbus Over USB Type-C architecture scheme. The SLIMbus is used for passing through the USB Type-C interface, and audio, data and control signals are transmitted between the host and the audio peripheral of the USB interface by the SLIMbus.

Meanwhile, because the UAC protocol has more hosts and peripherals and has wide user foundation, the invention provides a solution for a dual-mode USB Type-C audio architecture, wherein the dual modes refer to a SLIMbus architecture mode and a UAC architecture mode. The problem is solved innovatively with the SLIMbus architecture mode, with the UAC architecture mode being inherited and adapted to a wide user base.

Mode 1 in dual mode is a conventional UAC audio architecture. UAC is an abbreviation for USB Audio Class, meaning USB Audio Class, following the USB Audio Device Class Specification standard protocol. And the UAC mode 1 is used as a general mode to be compatible with the existing UAC host and the existing peripheral.

Mode 2 in the dual mode is an innovative design SLIMbus Over USB Type-C architecture. The audio signal is transmitted between the host and the peripheral through the SLIMbus, and the control signal and the data signal can be transmitted through the SLIMbus after the SLIMbus channel is established. And the peripheral side SLIMbus-I2S translation bridge of mode 2, if implemented using programmable logic devices, may be reconfigured as a SoundWire-I2S translation bridge. The corresponding whole architecture can be reconstructed into a SoundWire Over (pass through) USB Type-C architecture.

Relationship of mode 1 to mode 2: the mode 1 and the mode 2 share the USB equipment control module and the peripheral AUDIO module. The USB device control module not only performs the UAC architecture USB-I2S conversion bridge function of mode 1, but also performs the device controller function of the SLIMbus architecture of mode 2: the mode 2 architecture AUDIO peripheral is designed into a special USB Device, shares the USB interface and the USB Device controller of the mode 1, and completes the initialization setting and control of the peripheral AUDIO module shared by the mode 1 and the mode 2.

Reconfigurable means that without changing hardware design, neither a PCB (printed circuit board) nor a patch is redesigned, but only a firmware upgrade manner is used to construct a digital audio transfer bridge with a low-power-consumption programmable logic device (such as an FPGA), and the transfer bridge circuit can be reconstructed according to the definition change.

Because the SLIMbus bus and the SoundWire bus are both in a dual-bus form, one is a clock line and the other is a serial data line, the electrical characteristics are compatible. The SLIMbus and SoundWire are MIPI protocol standards, but SLIMbus is a mature standard protocol, SoundWire is a well-established standard which is not yet published; SoundWire will have further advantages and adaptability as a successor.

Firstly, designing a digital audio switching bridge into a SLIMbus-I2S switching bridge to realize audio peripherals such as SLIMbus Over USBType-C architecture earphones and the like. After the SoundWire bus protocol is formally released in the future, the SLIMbus bridge can be reconstructed into the SoundWire bridge through a hardware programming technology, so that the peripheral becomes a SoundWire bus peripheral. The SLIMbus bus that traverses the USB interface also becomes a SoundWire bus. The whole architecture correspondingly becomes a SoundWire Over (crossing Over) USBType-C architecture.

A pure digital dual mode audio signal transmission system architecture, refer to fig. 3, a pure digital dual mode audio signal transmission system architecture diagram >

The framework is composed of a host, a peripheral and interactive signals between the host and the peripheral.

The host side part comprises a CC controller module, a power management module, a forward and reverse insertion channel switching module, a USB Type-C receive, a CPU system module and a host CODEC module.

The peripheral side part comprises a USB device control module, a SLIMbus conversion bridge module, a peripheral CC control module, a peripheral AUDIO module, a peripheral power supply module and a USB Type-C Plug.

Interaction signals between the host and the peripheral: USB D +/D-bus, mode 2 audio bus, channel configuration CC bus, power supply line, common ground.

A host-side section:

a CC controller module for completing the positive and negative insertion connection state of the host via the CC bus

And (5) identifying. As an option of this embodiment, signal handshake interaction may be performed between the CC bus and the peripheral CC control module on the peripheral side, so as to complete acquisition of the peripheral tag, initialization of the host identity and the peripheral AUDIO module. At this time, the CC controller is required to support the USB PD protocol, so that it can read the EMCA (Electronically Marked Cable Assembly) peripheral electronic tag in the peripheral identification module through the CC bus. The peripheral identification module can also identify whether the host supports the audio peripheral through the CC bus.

The power management module is responsible for the power management of the host and must support the USB OTG function,

with the ability to power the peripheral.

The forward and reverse channel switching module can switch the digital audio frequency sent by the host CODEC module

The physical signal lines are routed to corresponding pins of the USB Type-C Receptacle.

USB Type-C receive, physical connection interface between host and peripheral,

the function of physical connection with the USB Type-C Plug of the peripheral equipment is completed.

A CPU system module including an application processor, a baseband processor, a memory,

The hardware system platform chips for radio frequency transceiving and the like are responsible for completing the establishment control and signal interaction of a digital audio channel of a host besides the functions of signal transceiving conversion and the like between the hardware system platform chips and a mobile network base station.

A host CODEC module including an Audio CODEC, an Audio DSP, a SPEAKER,

RECEIVER, audio amplifier, etc. And the forward and backward plugging channel switching module is connected with the forward and backward plugging channel switching module by a digital audio bus.

Peripheral side portion:

the USB equipment control module completes 2 functions: mode 1 USB-I2S bridge conversion

A function; mode 1, mode 2 share the USB peripheral controller function. The system has a certain size of FLASH storage space, and stores firmware codes of the reconfigurable conversion bridge module and DSP codes and initialization setting data in the peripheral CODEC.

As a peripheral controller, the USB device control module has the capability of identifying peripheral basic information. These pieces of information are: this is firstly a peripheral for the SLIMbus bus, which also supports the UAC architecture.

As a peripheral controller, a USB device control module and a CPU system module on the host side carry out signal handshake interaction by using a USB bus; the control bus is connected with the peripheral AUDIO module to complete the initialization and register setting of the peripheral AUDIO module; and the reconfigurable conversion bridge module is connected with the reconfigurable conversion bridge module through the control bus to complete code downloading and setting control of the reconfigurable conversion bridge module. And loading of firmware codes and DSP codes is completed during power-on, and the control of the audio channel is established.

As a USB-I2S conversion bridge, the USB device control module also performs packing and unpacking conversion of the I2S data format and the USB data format of the mode 1.

And the peripheral CC control module completes the insertion and identification functions of the USB Device. Making

The main machine side CC controller module is optional and can also be used as a peripheral authentication function, has the capability of identifying peripheral basic information, and performs signal handshake interaction with the CC controller module on the main machine side CC bus; as an alternative, it can also be used as a controller for the digital audio bus channel setup of mode 2.

The conversion bridge module completes the digital audio bus conversion function of the mode 2,

such as SLIMbus-I2S bridge conversion, SoundWire-I2S bridge conversion, etc. When the conversion bridge is implemented by a hardware programmable circuit such as an FPGA (field programmable gate array), the conversion bridge module also has reconfigurable features. At this point, the conversion bridge circuit may be reconstructed according to the definition change. At present, a digital audio switching bridge is designed into a SLIMbus-I2S switching bridge, and a peripheral is constructed into a SLIMbus audio peripheral. After the SoundWire bus protocol is formally released in the future, the SLIMbus bridge can be reconstructed into the SoundWire bridge through a hardware programming technology, so that the peripheral equipment can be changed into the SoundWire bus audio peripheral equipment only through a software upgrading mode without changing hardware.

The peripheral AUDIO module comprises an AUDIO CODEC, a microphone DAC, an AUDIO DAC,

Audio amplifiers, man-machine interaction interfaces, speech, microphones, etc. The audio CODEC also includes an I2S HUB function and an ADSP audio signal processor function to perform the selection or fusion process of the I2S signal.

Peripheral power supply module obtained from USB Type-C Plug VBUS or VCONN pin

And taking a power supply and converting the power supply into the voltage required by each module at the peripheral side.

USB Type-C Plug, the physical connection interface between the peripheral and the host, accomplish and

the USB Type-C Receptacle of the host computer has the function of plugging.

Mode 2SLIMbus channel establishment for interactive signaling between a host and a peripheral

How the digital audio bus passes through the USB Type C interface in mode 2 is described as follows: in dual mode, there are two channels that can be used to establish the channel of the SLIMbus bus, see < fig. 3 a pure digital dual mode audio signal transmission system architecture diagram > mode 2 channel 1, mode 2 channel 2. X, y are defined in fig. 3 as SLIMbus clock and data lines of peripheral mode 2; let X, Y be defined as the SLIMbus clock and data lines of

host mode

2, 1, 2 representing two alternative channels: channel 1, channel 2. The SLIMbus is to pass through the USB Type-C interface, namely, four signal lines X1/Y1 and X2/Y2 are sent to X1/Y1 and X2/Y2 of the host side from B6, B7, A8 and B8 pins of the USB Type-C Plug of the peripheral side through the USB Type-C interface and the positive and negative insertion channel switching module. SLIMbus channel establishment is illustrated with reference to fig. 4a, 4b, 5a, 5 b. The forward and reverse insertion channel switching module is composed of three two-way single-pole double-throw switches MUX0, MUX1 and MUX2, wherein the two-way single-pole double-throw switches include a switch control signal SW and a channel on-off enable signal EN.

In fig. 4a and 4b, X1, Y1, X2, Y2 represent the four signal lines of the digital audio bus of the host-side module 2, X1, Y1, X2, and Y2 represent the four signal lines of the digital audio bus of the peripheral module 2, and when the switch SW0, the switch SW1, and the switch SW2 are thrown upward at the same time. In fig. 5a and 5b, X1, Y1, X2, Y2 represent the four signal lines of the digital audio bus of the host-side module 2, X1, Y1, X2, and Y2 represent the four signal lines of the digital audio bus of the peripheral module 2, and when the three switches SW0, SW1, and SW2 are thrown downward at the same time.

The USB Type-C interface supports monitoring of positive and negative insertion, positive insertion and reverse insertion, is completed by the CC controller and reports to the CPU system module; the switching command of the positive and negative interpolation channels is issued by the CPU system module and is executed by controlling 3 switch control lines SW0, SW1 and SW2 to simultaneously throw up or throw down. The on-off instruction of the positive and negative interpolation channels is given by the CPU system module, and the signal channels of the change-over switches are communicated or disconnected by controlling 3 enabling signal lines EN0, EN1 and EN 2. The initial state EN0 is an enabling state, namely the USB channel keeps a through state at any time; the initial states EN1 and EN2 are disable off states, that is, the mode 2 digital audio bus channel is turned off by default, and the mode 2 digital audio channel is turned on only when the inserted peripheral device is approved by the host.

Combining fig. 3, fig. 4a, fig. 4b, fig. 5a, fig. 5b and the USB Type-C interface specification, it seems that the channel 2 is the optimal channel scheme for SLIMbus traversal (OVER) USB Type-C. Because the SBU1/SBU2 of the A8/B8 pin of the USB Type-C interface has stronger self-defined attribute, is more standard and has relatively simple circuit structure, the forward and reverse insertion channel switching module at the host side can be realized by using a double-path single-pole double-throw switch.

CC bus for channel allocation of interactive signals between host and peripheral

The CC bus is used for finishing the identification of the positive and negative plug connection states of the host. As an option, when the peripheral CC control module is used as a device controller, the CC line can also be used as an interactive bus between a host and the peripheral to complete the control setting of the device identification and the audio module, and the like

Host positive and negative plug connection state identification and CC behavior, see fig. 6a and 6b for CC behavior description diagrams. FIGS. 6a and 6b are taken from USB Type-C Cable and Connector Specification Release 1.2/March25, 2016.

To define the behavior of CC, two resistors Rp, Rd are introduced; variations in the actual device are possible, e.g., Rp may be replaced with a current source; under the initial condition, an Rp pull-up is arranged at the DFP CC end, and an Rd pull-down is arranged at the UFP CC end; the Vconn pin of Power Cable has an Ra pull-down (in some cases a pure resistor, in some cases a load); the DFP has the ability to recognize Rd and Ra, that is, the DFP can distinguish the connection of UFP or the Power Cable and CC directions by recognizing Rd and Ra; the UFP determines the insertion direction by the voltages of two CC pins in sequence (CC over OV).

USB2.0 data line for interactive signals between host and peripheral

The D +/D-data line of USB2.0 is used as the interactive bus between the host and the control module of the peripheral USB device to complete the functions of code downloading, software debugging, signal transmission and the like between the host and the peripheral.

Power supply line and grounding line for interactive signals between host and peripheral

And completing power transmission between the host and the peripheral equipment, and providing signal mirror image loops of the USB D +/D-, mode 2 digital audio bus and the CC bus.

Table 1 is a USB Type-C host status identification table, a USB Type-C host connection status identification table, and describes that the host machine judges whether UFP or Power Cable is connected by sensing the resistance of two CC pins, and judges whether the UFP or Power Cable is connected, and judges whether the UFP or Power Cable is inserted or inserted, or whether the UFP or Power Cable is inserted or not. Wherein, DFP is an abbreviation of Downstream Facing Port, which may be understood as a host CC controller, and UFP is an abbreviation of Upstream Facing Port, which may be understood as an Upstream Port, which may be understood as a peripheral side device control module.

TABLE 1

Interaction flow between host and peripheral

When the host is a device that satisfies the SLIMbus Over USB Type-C architecture, the peripheral operates on the SLIMbus mode. See < interaction flow between SLIMbus Over USB Type-C host and peripheral > fig. 7 for peripheral usage flow.

And when the host does not satisfy the SLIMbus Over USB Type-C architecture but only satisfies the UAC architecture, the peripheral works in the UAC mode. At this time, the interaction between the peripheral and the host is completely designed according to the UAC specification. The interaction process in the UAC mode is shown in fig. 8 as a working flow diagram of the UAC mode of the dual-mode peripheral when the host only supports the UAC architecture.

In the flowchart of fig. 7, step S709 may also be implemented in another manner: the < SLIMbus transfers the peripheral configuration information > instead of the < USB bus transfers the peripheral configuration information >. The host side becomes: the CPU system module issues a peripheral configuration information device controller through a SLIMbus; the peripheral side becomes: the device controller obtains the configuration information from the SLIMbus bus and updates the setting of the peripheral AUDIO module.

Step S710: change from < USB bus pass peripheral configuration complete > to < SLIMbus bus pass peripheral configuration complete >. The peripheral side becomes: the peripheral AUDIO module informs the host through the SLIMbus, and the configuration of the peripheral AUDIO module is completed; the host side becomes: the CPU system module learns from the SLIMbus that the peripheral AUDIO module configuration is complete.

Step S711, the < SLIMbus channel transfers audio and USB bus transfers peripheral data > to < SLIMbus channel transfers audio, control and data information >.

Through the above description of the embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but the former is a better implementation mode in many cases. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (e.g., ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal device (e.g., a mobile phone, a computer, a server, or a network device) to execute the method according to the embodiments of the present invention.

Example 2

The present embodiment provides a pure digital SLIMbus/UAC dual mode audio signal transmission system.

The audio signal transmission system is described in fig. 9 as a pure digital SLIMbus/UAC dual-mode audio signal transmission system architecture >.

The architecture is composed of a peripheral, a host and interactive signals between the host and the peripheral. Peripheral equipment and

the host has two working modes, namely a UAC mode, and I2S is packaged into a USB data format (I2S OverUSB) for transmitting audio signals; mode 2, SLIMbus mode, uses SLIMbus directly across the USB Type-C interface to pass audio signals. The control signals and the data signals both travel through the USB D +/D-bus.

The peripheral side part comprises a USB device control module, a conversion bridge module, a peripheral AUDIO module, a peripheral power supply module, a USB Type-C Plug and Rd ground resistor.

The host side part comprises a CPU system module and a host CODEC module, and also comprises a CC controller module, a power management module, a forward-transmission-insertion channel switching module and a USB Type-C Receptacle. The forward and reverse interpolation channel switching module is realized by a simple double-channel single-pole double-throw switch. The USB D +/D-connection conforms to the USB Type-C Receptacle pin definition completely: a6 short circuit B6 connects with D + signal line, A7 short circuit B7 connects with D-signal line.

Interaction signals between the peripheral and the host: USB bus, SLIMbus, CC bus, power supply line, and common ground line. The SLIMbus goes through channel 2 and connects the SLIMbus to the A8/B8(SBU1/SBU2) pins of the USB Type-C Plug.

Example 3

Based on the audio signal transmission system architecture of embodiment 2, a scalable pure digital SLIMbus/UAC dual-mode earphone is designed. See < fig. 10SLIMbus & UAC dual mode headphone schematic >.

The earphone consists of two parts: one part is the SLIMbus & UAC dual-mode earphone adapter circuit board, and the other part is the traditional earphone body (including speaker, microphone, drive-by-wire button and earphone cable, i.e. the other parts of the traditional earphone except the plug).

The switching circuit board mainly comprises a USB device controller module, a reconfigurable switching bridge module, an earphone AUDIO module and an earphone power supply module, and six parts of USB Type-C Plug and Rd grounding resistors. The USB Type-C Plug is directly soldered on the adapter circuit board.

The dual mode earphone has the following features

Have UAC digital earphone function

Having SLIMbus digital earphone functionality

The earphone has two working modes: a UAC mode and a SLIMbus mode, the SLIMbus mode having priority.

In the SLIMbus mode, audio signals are transmitted between the earphone and the host through a SLIMbus, and control signals and man-machine interaction signals (volume increase and decrease, conversation, pause and the like of an earphone which is a wired control key) are transmitted through a USB D +/D-bus.

And when in the UAC mode, the UAC mode transmits control signals, audio signals and data signals to the host through a USB bus.

The Device tag is implemented in a USB Device tag manner.

The earphone conversion bridge module is realized by using an FPGA, and FPGA firmware codes can be downloaded into FLASH in a USB device controller module through a USB interface and loaded when being powered on. In order to shorten the firmware loading time, the loading bus selects an SPI bus.

The earphone can be upgraded through FPGA firmware, a SLIMbus-I2S bridge can be reconstructed into a SoundWire-I2S bridge, a SLIMbus is replaced by a SoundWire bus, and accordingly the earphone is changed into a dual-mode digital earphone with a USBType-C plug of another SoundWire bus.

The SLIMbus and UAC dual-mode earphone has the following module functions:

1) USB equipment control module: 2 functions are completed: mode 1 USB-I2S bridge conversion

A function; mode 1, mode 2 share the USB peripheral controller function. The device has a certain size of FLASH storage space, and stores FPGA firmware codes of the reconfigurable conversion bridge module and DSP codes and initialization setting data in the earphone AUDIO module. And loading of firmware codes and DSP codes is completed during power-on, and the control of the audio channel is established.

As a USB-I2S conversion bridge, the USB device control module completes the packaging and unpacking conversion between the I2S data format of the UAC module and the USB data format.

As a USB peripheral controller, the USB device control module has the capability of identifying the basic information of the headset. These pieces of information include: this is a SLIMbus & UAC dual mode headset, supporting both SLIMbus and UAC headset modes. The SLIMbus is defined at the A8/B8 pin of the USB Type-C Plug.

As a peripheral controller, a USB device control module and a CPU system module on the host side use a USB bus to carry out signal handshake interaction to complete the functions of code downloading, debugging, data updating and the like. The earphone AUDIO module is connected with the SPI control bus to complete initialization and register setting of the earphone AUDIO module; and the earphone AUDIO module transmits uplink and downlink data in a UAC mode by using an I2S bus I2S 1. The conversion bridge module is connected through the SPI bus, loading of FPGA firmware codes and register data updating, namely reporting of state information are completed when the power is on. As a peripheral controller, the USB device control module also performs a mode switching function between the SLIMbus earphone mode and the UAC mode.

2) The earphone body:

including earphone loudspeaker, MIC, drive-by-wire button, earphone cable etc. all parts except the plug of traditional 3.5mm earphone promptly.

3) The earphone power supply module:

and acquiring a power supply from the VBUS of the USB Type-C Plug, converting the power supply into voltages required by each module on the earphone side, and managing the power-on sequence.

4) Rd ground resistance: the identification is that the Device is a USB Device, and the CC bus of the host side completes the insertion identification of the earphone USB Device by detecting the grounding resistance.

5) Earphone AUDIO module:

including audio frequency I2S HUB, CODEC, MIC DAC, earphone amplifier, earphone drive-by-wire discernment and code etc. have the SPI interface, have two I2S interfaces, an I2S interface connects the conversion bridge module, and another I2S interface connects USB equipment controller module.

6) And the bridge module is converted to complete the SLIMbus-I2S conversion, and is realized by a low-power-consumption FPGA (field programmable gate array). Through the FPGA firmware upgrading mode, the SLIMbus-I2S bridge can be reconstructed into a SoundWire-I2S bridge, the SLIMbus is replaced by a SoundWire bus, and accordingly, the earphone is changed into another SoundWire/UAC dual-mode digital earphone only through the software upgrading mode.

The using process of the SLIMbus & UAC dual-mode earphone comprises the following steps:

when the host is a device that satisfies the SLIMbus Over USB Type-C architecture, the headset operates in mode 1, i.e., SLIMbus mode. See < interaction flow diagram between SLIMbus Over USB Type-C host and headset > of fig. 11 using flow.

When the host does not satisfy the SLIMbus Over USB Type-C architecture but only satisfies the UAC architecture, the headset operates in the UAC mode. See < fig. 12 dual mode earpiece UAC mode work flow diagram when host supports only UAC architecture >).

The technical effects of the SLIMbus and UAC dual-mode earphone are as follows:

1) the SLIMbus and UAC dual-mode earphone is good in universality, a SLIMbus mode is used when a host meets the SLIMbus Over USB Type-C framework, and a UAC mode is used when the host only meets the UAC framework.

2) The SLIMbus & UAC dual-mode earphone scheme has low power consumption when the SLIMbus mode is used, and a SLIMbus low-power digital audio bus is used for audio signal transmission; compared with the UAC scheme, the power consumption waste that the AP cannot sleep when the USB works and the USB is converted from I2S to USB and from USB to I2S is saved. Overall evaluation shows that SLIMbus mode may save power by half compared to UAC mode.

3) The SLIMbus & UAC dual mode headset scheme is low cost. Compared with the analog-digital hybrid earphone, the rear-stage circuit does not need to be added with a double-circuit earphone changeover switch chip; compared with the analog-digital hybrid earphone with time division multiplexing channels, the front-stage USB of a USB port and the earphone signal change-over switch are further omitted.

4) The HIFI performance of the SLIMbus & UAC dual-mode earphone is more guaranteed. Firstly, the scheme is purely digital, and digital signals are not easily interfered; secondly, compared with the analog-digital hybrid earphone, the rear-stage circuit does not need to be added with a double-circuit earphone change-over switch, and audio signal insertion loss caused by the switch is avoided. Compared with the analog-digital hybrid earphone with time division multiplexing channels, the earphone signal switching switch and the USB signal switching switch are further omitted, and audio signal insertion loss caused by the switch is further avoided.

5) The SLIMbus & UAC dual-mode earphone scheme can completely meet the requirement of mobile call delay when the SLIMbus mode is used. The audio channel is completely the same as the traditional mobile phone, and the natural call delay is also the same as the traditional mobile phone, so that the call delay requirement is met.

6) According to the earphone SLIMbus & UAC dual-mode earphone scheme, a traditional audio architecture is adopted in software, earphone development difficulty is relatively low, the whole digitalization process of the earphone is advanced, and a product can seize the market first-time machine easily. The digital earphone design which completely meets the mobile call delay requirement under the pure UAC architecture needs to wait for the improvement of the UAC standard and the optimization of a host hardware platform and a software architecture, and can be realized only in the future.

As an alternative, the SLIMbus channel may also be defined at the A6/A7 pin of the USB Type-C Plug, i.e., the multiplexing USB D +/D-channel. The peripheral equipment and the host equipment interact through a CC bus; the device controller is implemented using a peripheral CC controller.

Example 4

In this embodiment, there is also provided a method for transmitting an audio signal, as shown in fig. 13, the method includes the following processing steps:

step S1302, after a terminal peripheral is connected to a terminal, the terminal peripheral determines a channel type used by the USB plug for signal transmission with the audio module, wherein the channel type includes a first transmission channel and a second transmission channel arranged between the USB plug and the audio module, the first transmission channel includes a USB audio UAC audio channel, and the second transmission channel includes a low-power inter-chip serial media SLIM bus audio channel;

step S1304, the terminal peripheral performs signal transmission between the USB plug and the audio module according to the determined channel type.

Optionally, before the channel type used for signal transmission between the terminal peripheral USB plug and the audio module, the method includes: the method comprises the steps that a terminal peripheral sends first notification information to a terminal, wherein the first notification information is used for indicating that the terminal peripheral supports the adoption of a second transmission channel for transmitting audio signals; and the terminal peripheral receives second notification information of the terminal, wherein the second notification information is used for indicating that the terminal supports the transmission of the audio signal by adopting the SLIM bus audio channel.

Example 5

In the embodiment, a terminal peripheral is also provided, and the structure of the terminal peripheral may adopt the structure shown in fig. 2, but is not limited thereto, for example, the terminal peripheral in the embodiment may have more or less structural features than the structure shown in fig. 2. The terminal peripheral provided by the embodiment comprises: the device comprises a Universal Serial Bus (USB) plug, an audio module and a device control module, wherein the device control module is connected with the USB plug and the audio module; the terminal peripheral further includes:

the first conversion bridge module is connected with the USB plug and the equipment control module and is used for converting the audio signals received from the USB plug from the USB format into the I2S format;

and the second conversion bridge module is connected with the USB plug and the device control module and is used for converting the audio signals received from the USB plug from the SLIMbus format into the I2S format.

It should be noted that, reference may be made to the relevant description in embodiments 1 to 3 for a preferred implementation of this embodiment, and details are not described here again.

It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A terminal peripheral, comprising: the device comprises a Universal Serial Bus (USB) plug, an audio module and an equipment control module; wherein the content of the first and second substances,

the device control module is configured to control a transmission channel used for signal transmission between the USB plug and the audio module, where the channel includes a first transmission channel and a second transmission channel, the first transmission channel includes a USB audio UAC-like audio channel, the second transmission channel includes a low-power inter-chip serial media SLIM bus audio channel, and the SLIM bus audio channel has a priority.

2. The terminal peripheral of claim 1, wherein the UAC audio channel is configured to convert audio signals received via the USB plug from a USB format to an inter-integrated circuit, IC, audio I2S format; and the SLIM bus audio channel is used for converting the audio signal received by the USB plug from a low-power consumption inter-chip serial media SLIM bus format into an I2S format.

3. The terminal peripheral of claim 1, further comprising: the first conversion bridge module is arranged on the first transmission channel and used for converting the audio signals received from the USB plug from the USB format into the I2S format.

4. The terminal peripheral of claim 3, wherein the first translation bridge module is built into the device control module.

5. The terminal peripheral of claim 1, further comprising: and the second conversion bridge module is arranged on the second transmission channel and is used for converting the audio signals received from the USB plug from the SLIMbus format into the I2S format.

6. The terminal peripheral of claim 5, wherein the second translation bridge module comprises a HUB.

7. The terminal peripheral of claim 5, wherein the second conversion bridge module is a programmable circuit module configured to obtain a firmware upgrade program from the device control module, wherein the firmware upgrade program is configured to convert the second conversion bridge module from a first function to a second function, wherein the first function is to convert audio signals from a SLIMbus format to an I2S format, and wherein the second function is to convert audio signals received from the USB plug from a Soundwire bus format to an I2S format.

8. The terminal peripheral of any one of claims 1-7, wherein the USB plug comprises: USBType-C plug.

9. A method of transmitting an audio signal, characterized in that,

after a terminal peripheral is connected with a terminal, the terminal peripheral determines a channel type adopted by a USB plug for signal transmission with an audio module, wherein the channel type comprises a first transmission channel and a second transmission channel which are arranged between the USB plug and the audio module, the first transmission channel comprises a USB audio UAC (universal serial bus) audio channel, the second transmission channel comprises a low-power inter-chip serial media SLIM bus audio channel, and the SLIM bus audio channel has priority;

and the terminal peripheral equipment transmits signals between the USB plug and the audio module according to the determined channel type.

10. The method of claim 9, wherein before the determining the type of channel used by the USB plug for signal transmission with the audio module by the terminal peripheral device, comprises:

the terminal peripheral sends first notification information to the terminal, wherein the first notification information is used for indicating that the terminal peripheral supports the transmission of audio signals by adopting the second transmission channel;

and the terminal peripheral receives second notification information of the terminal, wherein the second notification information is used for indicating that the terminal supports the transmission of audio signals by adopting an SLIM bus audio channel.

11. A terminal peripheral, comprising: the device comprises a Universal Serial Bus (USB) plug, an audio module and a device control module, wherein the device control module is connected with the USB plug and the audio module; the terminal peripheral further comprises:

a first conversion bridge module connected with the USB plug connection and the equipment control module and used for converting the audio signals received from the USB plug from a USB format into an I2S format;

a second conversion bridge module connected with the USB plug connection and the device control module for converting audio signals received from the USB plug from a SLIMbus format to an I2S format, wherein the conversion of the audio signals from the SLIMbus format to the I2S format has priority.