KR20230145767A - Method of switching interface in optical disc drive - Google Patents

Abstract

This specification relates to a method for switching interfaces of an optical disk drive. A method for switching an interface of an optical disk drive according to an embodiment includes the steps of: receiving a request to transmit a USB descriptor from a host, transmitting a default USB descriptor whose interface class is defined as a vendor-specific class to the host; waiting for transmission of a vendor-specific command from the host; If a vendor specific command is not sent, performing a USB reset; and transmitting a second USB descriptor whose interface class is defined as a mass storage class to the host.

Description

{Method of switching interface in optical disc drive}

This specification relates to a method of switching interfaces in an optical disk drive, and more specifically, to a method of connecting an optical disk drive to various types of hosts to be compatible.

An optical disk device or optical disk drive that can play or record optical disks such as CD (Compact Disc), DVD (Digital Versatile Disc), and BD (Blu-ray Disc) that can record and store data. ODD) is used as a peripheral device for desktop computers (PCs) or laptop computers.

Recently, optical disk devices have been released as external rather than built into PCs or laptops, and are used by connecting to PCs or laptops through a USB interface.

The USB device driver, which enables connection of an external optical disk device to a PC or laptop computer, has been designed to be compatible with existing operating systems such as Windows OS (Operating System), Mac OS, and Linux OS.

Recently, as the specifications of smart devices such as smart phones and smart pads have increased, users are using smart devices as replacements for or in addition to PCs and laptop computers. Accordingly, the need to connect external optical disk devices to smart devices is increasing.

To connect an optical disk device to smart devices such as Android-based tablets and smartphones, iOS-based iPhones and iPads, or Chrome Books, it is compatible with new OS-based devices such as smart devices and Chromebooks. Development of USB device drivers is required.

This specification takes this situation into consideration, and the purpose of this specification is to provide an optical disk device that is compatible with new OS-based devices.

The specific purpose of this specification is to provide an interface that allows an optical disk device to be connected to various types of devices.

An interface conversion method of an optical disk drive according to an embodiment for realizing the above-mentioned problem includes the steps of: receiving a request for transmission of a USB descriptor from a host, transmitting a default USB descriptor whose interface class is defined as a vendor-specific class to the host; waiting for transmission of a vendor-specific command from the host; If a vendor specific command is not sent, performing a USB reset; And transmitting a second USB descriptor whose interface class is defined as a mass storage class to the host.

An optical disk drive according to another embodiment includes a disk drive unit for writing data to or reading data from an optical disk; An interface unit for connecting to a host to exchange data or commands; and a control unit for controlling the disk drive unit and the interface unit to record data transmitted from the host to an optical disk or to read data from the optical disk and transmit it to the host. The interface unit defines the interface class as a vendor-specific class. Store the default USB descriptor and a second USB descriptor that defines the interface class as a mass storage class, first transmit the default USB descriptor to the host during USB enumeration with the host, and configure the default USB descriptor based on the response from the host. It is characterized by determining to convert the descriptor to a second USB descriptor.

Accordingly, the optical disk device can be connected not only to computers employing conventional operating systems such as Windows, Mac, and Linux, but also to smart devices such as smart phones and tablets.

In addition, the hardware cost of the optical disk device can be reduced by eliminating the need to add a hardware switch for switching the interface class to connect the optical disk device to various devices.

In addition, user convenience can be improved because the user of the optical disk device can eliminate the inconvenience of having to manually operate the switch by directly distinguishing the OS of the device to be connected.

Figures 1A and 1B respectively illustrate the connection between an optical disk device and a laptop and the connection between an optical disk device and a smart phone;
Figure 2 shows the communication process for USB Enumeration when an optical disk device is connected to a host via USB.
Figure 3 shows a USB descriptor of a conventional optical disk device;
Figure 4 shows the USB device setup process when a conventional optical disk device is connected to a PC.
Figure 5 shows a process in which USB device setup fails when a conventional optical disk device is connected to a smart device running a new OS.
Figure 6 shows the class code defined in the USB specification,
Figure 7 conceptually shows an example in which an optical disk device has two or more sets of USB descriptors according to an embodiment of this specification;
Figure 8 shows the configuration of an optical disk device to which an embodiment of this specification is applied in functional blocks;
Figure 9 shows the USB device setup process when the optical disk device according to an embodiment of this specification is connected to a smart device;
Figure 10 shows the configuration of vendor-specific commands,
FIG. 11 illustrates a USB device setup process when an optical disk device according to an embodiment of this specification is connected to a PC.

Hereinafter, an embodiment of an interface switching method of an optical disk drive will be described in detail based on the accompanying drawings.

Figures 1A and 1B illustrate the connection between an optical disk device and a laptop and the connection between an optical disk device and a smart phone, respectively.

The optical disk device or optical disk drive according to an embodiment of this specification is connected to a PC or laptop with Windows OS, Mac OS, or Linux OS installed through a USB (Universal Serial Bus) interface without a separate hardware switch, It can also be connected to smart devices running Android OS, iPhones and iPads running iOS, and Chromebooks running Chrome OS.

Figure 2 shows the communication process for USB Enumeration when an optical disk device is connected to a host via USB. USB Enumeration detects whether a new device is connected to the bus of the USB interface, recognizes the device, and This means loading the appropriate driver.

The USB Enumeration process can be briefly summarized as follows. When a USB device is connected to a host, the host's controller uses temporary information to request information from endpoint 0 of the device, receives device descriptor information from the device, and assigns an appropriate address to the device. The USB enumeration process is completed when all descriptor information is received by requesting the remaining descriptor information using the address.

The USB interface is a standard that supports operation by connecting devices to a host. PC peripheral devices such as keyboards and mice, external storage devices, and smart phones connected to a PC also use the USB protocol.

The USB interface supplies power to connected devices, and USB 2.0 and higher have data transmission and reception speeds of tens of megabytes per second, so there is no problem with connecting a large number of USB devices to one host.

The host identifies connected USB devices using vendor ID and product ID, which can be processed separately by grouping them into classes. For example, peripheral devices such as a mouse or keyboard can use the functions of the already existing HID (Human Interface Device) class without the need to write a separate device driver.

Basic information about the USB device is contained in the descriptor. When a USB device is connected to a host, configuration information is exchanged. During this process, the USB device transmits descriptor information to the host, and based on this, the host learns the type of connected USB device and determines the characteristics of the USB device. You can set the data transmission speed or polling cycle accordingly.

As shown in FIG. 2, when an optical disk drive, which is a USB device, is connected to a host, for example, a PC, the host detects that the device is connected to the bus of the USB interface and checks the data transfer speed of the device.

Afterwards, the host requests a device descriptor from the USB device, and the USB device transmits the device descriptor to the host.

Afterwards, the host resets the connection with the USB device and reassigns the address.

The host requests a configuration descriptor from the USB device, and the USB device transmits the configuration descriptor.

Additionally, the host requests an interface descriptor from the USB device, and the USB device transmits the interface descriptor.

Afterwards, the host loads the driver appropriate for the connected USB device based on the transmitted descriptor, and the USB device is ready to be used.

There are several types of USB descriptors, such as device descriptor, configuration descriptor, interface descriptor, and endpoint descriptor, because the USB interface can support various functions.

The device descriptor contains the most basic information about the device. A USB device has one device descriptor, which contains product ID (ProductID) and vendor ID (VendorID) information. Additionally, the device descriptor contains information about how many configurations the device has and class information.

The configuration descriptor contains information related to environmental settings. A USB device can have multiple configuration descriptors, which contain information such as the number of interfaces and power consumption information. One USB device generally has one setting, and for a specific USB device, multiple setting information may exist.

An interface descriptor contains information about one function. One USB device can provide multiple functions, such as mouse, keyboard, and scanner, and one interface can be assigned to each function. The interface descriptor contains information such as the interface number and number of endpoints, and one interface can have multiple endpoints.

An endpoint descriptor can contain information about one endpoint. An endpoint corresponds to a passage or pipe through which actual communication occurs between a host and a device. The endpoint descriptor contains information such as the endpoint number, transmission type, and direction. The endpoint transmission type includes Control, Interrupt, Isochronous or Bulk, and by default, endpoint number 0 is the Control type. It is used as.

Figure 3 shows a USB descriptor of a conventional optical disk device, and the endpoint descriptor is omitted.

All USB devices have a unique interface class depending on the type and function of the device, and when connected to a host, the host recognizes the connected device by reporting this to the host in the form of a USB descriptor during setup or control.

In the USB descriptor of the conventional optical disk device of FIG. 3, the device descriptor defines the number of settings as 1 (bNumConfigurations = 1), and the configuration descriptor defines the setting value as 1 (bConfigurationValue = 1) The number of interfaces is defined as 1 (bNumInterfaces = 1), the interface descriptor defines the number of endpoints as 2 (bNumEndpoints = 2), and the interface class is defined as Mass Storage Class (MSC). There is (bInterfaceClass = Mass Storage Class).

An optical disk device that is generally connected to a PC and used as an external storage device has an MSC interface class, as shown in Figure 3, and conventional OSs such as Windows OS, MacOS, and Linux OS recognize it as a storage device. Applications running on the corresponding OS can communicate with the optical disk device.

Figure 4 shows the USB device setup process when a conventional optical disk device is connected to a PC, and Figure 5 shows a process in which USB device setup fails when a conventional optical disk device is connected to a smart device running a new OS. .

During the USB enumeration process, the host PC requests a descriptor from the optical disk device, which is a USB device (GET_DESCRIPTOR), and the optical disk device transmits the device descriptor, configuration descriptor, and interface descriptor to the PC as shown in FIG. 3. At this time, the interface descriptor transmitted to the host may define the interface class as MSC.

Next, in the case of FIG. 4 where the PC is the host, the application running on the PC opens a connection with the optical disk device for transmitting and receiving large amounts of data, and the optical disk device can communicate with the application.

On the other hand, in the case of Figure 5 where a mobile terminal such as a smart device is the host, an application running on the operating system of the mobile device cannot open a connection for transmitting and receiving large amounts of data to the optical disk device.

The host can define the USB device type, the type of data transfer to be used, the interval at which data will be sent, or the communication speed. When the USB Enumeration process is successfully completed, the user application installed on a host running a conventional OS such as Windows OS, Mac OS, or Linux OS can communicate with the connected USB device without any particular restrictions. However, in the case of iOS, Android OS, and Chrome OS, when a USB device with the MSC class is connected, communication between the connected USB device and the user application may not be allowed depending on the operating system's policy.

Figure 6 shows the class code defined in the USB specification.

Base Class 08h is defined for Mass Storage devices and can be used in interface descriptors. Base Class FFh is defined for a vendor (vendor-specific) and can be used in both device descriptors and interface descriptors.

In order for an optical disk device, which is a USB device, to access a smart device that runs on iOS, Android OS, or Chrome OS rather than the conventional OS, a vendor-specific Type that can be specified by the vendor rather than the typical Device Type during the USB enumeration process is required. It must be recognized as. For this purpose, the class code of the optical disk device can be defined as Vendor-specific, and the interface class can be defined as Vendor-Specific Class in the interface descriptor. However, in this case, it becomes difficult to use the optical disk device on a PC running Windows OS, Mac OS, or Linux OS.

In order to solve this problem, the optical disk device according to an embodiment of this specification supports not only the MSC class but also the Vendor-Specific class, so that it can be used not only on traditional OA-based hosts but also on mobile or smart devices with new OSs. Make it possible to operate accordingly.

That is, the optical disk device according to an embodiment of this specification stores two or more sets of USB scripts and allows switching the settings of the USB scripter depending on the connected host, and sends information of the application running on the host. Based on this, you can change the settings of the USB scripter.

FIG. 7 conceptually illustrates an example in which an optical disk device includes two or more sets of USB descriptors according to an embodiment of this specification.

As shown in Figure 7, the optical disk device includes a first USB descriptor set and Windows OS for delivery to a host running iOS, Android OS, Chrome OS, etc. applied to Apple mobile terminals such as iPhone, iPad, and iPod. , a second USB descriptor set can be prepared for delivery to a host running a traditional OS such as Mac OS or Linux OS.

The first USB descriptor set may define an interface class as a Vendor-Specific class in the interface descriptor, and the second USB descriptor set may define an interface class as a Mass Storage class in the interface descriptor.

The optical disk device can switch between two or more sets of USB descriptors based on information transmitted from a connected host during the USB enumeration process.

For example, during the USB enumeration process, the optical disk device transmits a first USB descriptor set whose interface class is defined as the Vendor-Specific class to the connected host, and when information corresponding to the Vendor-Specific class is transmitted from the host, Based on this, it can be determined that the host is a host that corresponds to the Vendor-Specific class, for example, an iPhone, iPad, or iPod loaded with iOS or a Chromebook with Chrome OS installed, and the interface class can be kept as is.

On the other hand, the optical disk device transmits the first USB descriptor set whose interface class is defined as the Vendor-Specific class to the connected host during the USB enumeration process, and if information corresponding to the Vendor-Specific class is not delivered from the host, Based on this, it was determined that the host was not a host corresponding to the Vendor-Specific class, but a PC or laptop running Windows/Mac/Linux OS, and USB enumeration was performed by converting the interface class to a second USB descriptor set defined as Mass Storage class. You can perform the process again.

Figure 8 shows the configuration of an optical disk device to which an embodiment of this specification is applied in terms of functional blocks.

The optical disk device or optical disk drive (ODD) 100 may be configured to include a control unit 110, a disk driver 120, and an interface unit 130.

The control unit 110 transmits data on an optical disk to the host according to a command from a host connected through the interface unit 130, for example, a smart device or a PC, or records data transmitted by the host on the optical disk. 120).

The disk drive unit 120 drives the optical pickup, spindle motor, sled motor, etc. under the control of the control unit 110 to record data transmitted from the host to the optical disk or read data from the optical disk and transmit it to the host. You can.

The interface unit 130 connects the ODD 100 to the host to serve as a conduit for exchanging data or commands and can also receive power from the host.

The interface unit 130 stores two or more sets of USB descriptors, including a default USB descriptor, and transmits the data to the host based on feedback from the host when it is connected to the host via a USB cable and performs a USB enumeration process. You can switch the USB descriptor.

That is, when the interface unit 130 is connected to the host via a USB cable and performs a USB enumeration process, it first targets connection with the mobile terminal and sets the vendor-specific class as the interface class. The first USB descriptor including, that is, the default USB descriptor, may be transmitted to the host.

If the host is an iOS smart device such as iPhone/iPad/iPod or a Chromebook, it opens a connection with the ODD (100) in response to the default USB descriptor and transmits a response to the default USB descriptor, and accordingly the interface unit (130) ) determines that the USB enumeration process is complete and maintains the interface class as is.

On the other hand, a laptop or PC-type host does not respond to the default USB descriptor, and if no response is sent from the host for a predetermined time (Timeout), the interface unit 130 determines that the host is a PC or laptop and mass storage A second USB descriptor including a class (Mass Storage Class) as an interface class may be transmitted to the host.

The host that has received the second USB descriptor opens a connection with the ODD (100), and the application running on the host can communicate with the ODD (100).

Figure 9 shows a USB device setup process when an optical disk device according to an embodiment of this specification is connected to a smart device.

In the USB enumeration process, the mobile smart device, which is the host, requests a descriptor from the optical disk device, which is a USB device (GET_DESCRIPTOR), and the optical disk device includes an interface descriptor with a vendor-specific class as the interface class. Transmits the default USB descriptor to the host.

The mobile smart device, which is the host, receives the USB descriptor transmitted by the USB device connected through the USB connector, checks the interface class defined in the interface descriptor of the USB descriptor, and determines that the interface class is a vendor-specific class. If so, the host's application opens a connection with the USB device to enable mass transfer of data to the optical disk device, and the host's application can transmit vendor-specific commands to the USB device. there is.

The optical disk device that has transmitted the default USB descriptor to the host waits for a vendor-specific command to be transmitted from the host for a predetermined time (timeout).

If a vendor-specific command is sent from the host before the timeout elapses, the optical disk device maintains the interface class as the vendor-specific class and communicates with the host's application. can be performed.

Figure 10 shows the configuration of vendor-specific commands.

When a host that has received a USB descriptor whose interface class is defined as a vendor-specific class opens a connection with a USB device, the host's application executes a pre-agreed vendor-specific command. is transmitted to the USB device, and the application is a program distributed by the company that released the optical disk device, so when receiving the USB descriptor defined as a vendor-specific class, a pre-negotiated vendor-specific command is sent. (Vendor-specific command) can be transmitted to a USB device.

When a connection with a USB device is opened, the application checks the USB descriptor transmitted by the connected USB device, and if the interface class is defined as a vendor-specific class in the interface descriptor of the USB descriptor, the vendor-specific class is Vendor-specific commands can be transmitted to connected USB devices.

As shown in FIG. 10, the vendor-specific command is an 8-byte long setup packet that can define the Device to Host direction and vendor type in the tmRequestType field.

Figure 11 shows a USB device setup process when an optical disk device according to an embodiment of this specification is connected to a PC.

During the USB enumeration process, the host PC requests a descriptor from the optical disk device, which is a USB device (GET_DESCRIPTOR), and the optical disk device contains a default interface descriptor with a vendor-specific class as the interface class. Send the USB descriptor to the host.

The host PC receives the USB descriptor transmitted by the USB device connected through the USB connector, checks the interface class defined in the interface descriptor of the USB descriptor, and, if the interface class is a vendor-specific class, No action can be performed because the connection with the USB device cannot be opened.

The optical disk device that has transmitted the default USB descriptor to the host waits for a vendor-specific command to be transmitted from the host for a predetermined time (timeout), but the host PC does not open a connection with the USB device. Because no action is taken, including sending a vendor-specific command, a timeout of, say, 5 seconds elapses.

Accordingly, the optical disk device performs a USB reset through software.

The host PC performs the USB enumeration process again and requests a descriptor from the USB device (GET_DESCRIPTOR), and the optical disk device changes the interface class from vendor-specific class to Mass Storage Class. ), and transmits the second USB descriptor including an interface descriptor with the interface class as Mass Storage Class to the host.

The host PC receives the USB descriptor transmitted by the USB device, checks the interface class defined in the interface descriptor of the USB descriptor, and if the interface class is Mass Storage Class, the host's application is connected to the USB device. Opens a connection with a USB device to enable mass data transfer with a phosphorescent disk device.

Afterwards, the optical disk device opens a USB connection with the host and can communicate with the host's application.

Therefore, the optical disk device according to the embodiment of this specification can be used not only on PCs but also on mobile devices by simply modifying the firmware without a hardware switch for switching interface classes.

The interface switching method of the optical disk drive described in this specification can be described as follows.

A method for switching an interface of an optical disk drive according to an embodiment includes the steps of: receiving a request to transmit a USB descriptor from a host, transmitting a default USB descriptor whose interface class is defined as a vendor-specific class to the host; waiting for transmission of a vendor-specific command from the host; If a vendor specific command is not sent, performing a USB reset; and transmitting a second USB descriptor whose interface class is defined as a mass storage class to the host.

In one embodiment, the method of switching an interface of an optical disk drive may further include performing data communication with an application of a host.

In one embodiment, when a vendor-specific command is sent, the interface class may remain a vendor-specific class.

In one embodiment, a USB reset may be performed when no vendor-specific commands are sent for a predetermined timeout.

In one embodiment, vendor-specific commands may be sent by an application running on the host.

In one embodiment, vendor-specific commands are not transmitted when the host is a terminal running on Windows OS, Mac OS, or Linux OS, and vendor-specific commands are not transmitted when the host is a terminal running on an OS other than Windows OS, Mac OS, and Linux OS. A command may be transmitted.

An optical disk drive according to another embodiment of this specification includes a disk drive unit for writing data to or reading data from an optical disk; An interface unit for connecting to a host to exchange data or commands; and a control unit for controlling the disk drive unit and the interface unit to record data transmitted from the host to an optical disk or to read data from the optical disk and transmit it to the host. The interface unit defines the interface class as a vendor-specific class. Store the default USB descriptor and a second USB descriptor that defines the interface class as a mass storage class, first transmit the default USB descriptor to the host during USB enumeration with the host, and configure the default USB descriptor based on the response from the host. You may decide to convert the descriptor to a second USB descriptor.

In one embodiment, the interface unit may transmit a default USB descriptor to the host when receiving a USB descriptor transmission request from the host, perform a USB reset if a vendor-specific command is not transmitted from the host, and transmit a second USB descriptor to the host. there is.

In one embodiment, the interface unit may maintain the interface class as a vendor-specific class when a vendor-specific command is transmitted.

In one embodiment, the interface unit may perform a USB reset when a vendor-specific command is not transmitted for a predetermined timeout.

The present invention is not limited to the described embodiments, and it is obvious to those skilled in the art that various modifications and changes can be made without departing from the spirit and scope of the present invention. Accordingly, such modifications or variations should be considered to fall within the scope of the claims of the present invention.

100: Optical disk drive (ODD) 110: Control unit
120: disk driving unit 130: interface unit

Claims (10)

Upon receiving a request to transmit a USB descriptor from a host, transmitting a default USB descriptor whose interface class is defined as a vendor-specific class to the host;
waiting for transmission of a vendor-specific command from the host;
If the vendor-specific command is not transmitted, performing a USB reset; and
An interface switching method of an optical disk drive comprising transmitting a second USB descriptor in which the interface class is defined as a mass storage class to the host. According to claim 1,
An interface switching method for an optical disk drive, further comprising performing data communication with an application of the host. According to claim 1,
When the vendor-specific command is transmitted, the interface switching method of an optical disk drive is characterized in that the interface class is maintained as the vendor-specific class. According to claim 1,
The USB reset is performed when the vendor-specific command is not transmitted for a predetermined timeout. According to claim 1,
An interface switching method for an optical disk drive, wherein the vendor-specific command is transmitted by an application running on the host. According to claim 1,
When the host is a terminal running on Windows OS, Mac OS, or Linux OS, the vendor-specific command is not transmitted, and when the host is a terminal running on an OS other than Windows OS, Mac OS, and Linux OS, the vendor-specific command A method for switching interfaces of an optical disk drive, characterized in that the is transmitted. a disk drive unit for recording data to or reading data from an optical disk;
An interface unit for connecting to a host to exchange data or commands; and
It is configured to include a control unit for controlling the disk drive unit and the interface unit to record data transmitted from the host to an optical disk or to read data from the optical disk and transmit it to the host,
The interface unit stores a default USB descriptor that defines the interface class as a vendor-specific class and a second USB descriptor that defines the interface class as a mass storage class, and transmits the USB descriptor to the host during USB enumeration with the host. An optical disk drive characterized in that it transmits a default USB descriptor first and determines whether to convert the default USB descriptor to the second USB descriptor based on a response from the host. According to clause 7,
The interface unit transmits the default USB descriptor to the host when receiving a request to transmit a USB descriptor from the host, performs a USB reset if a vendor-specific command is not transmitted from the host, and transmits the second USB descriptor to the host. An optical disk drive characterized in that it transmits data. According to clause 8,
The interface unit maintains the interface class as the vendor-specific class when the vendor-specific command is transmitted. According to clause 8,
The interface unit performs the USB reset when the vendor-specific command is not transmitted for a predetermined timeout.

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