CN1981274A - Method for managing the plug-in or removal of a memory card into or from a card reader and apparatus for use in said method - Google Patents

Abstract

This solution involves the processing of inserting or pulling out a memory card into or out of a memory card reader (11) which itself is connected to a central device (10). The insertion or removal of a memory card into or out of the memory card reader (11) is not reported to the central device (10) via the bus connection (13), which may be a USB bus connection. This causes confusion for the user and the central device (10) such as a DVD player. This phenomenon can also be caused if the memory card is removed from the card reader (11). Although the card has been removed, however, the card's content or file directory is still displayed on the player's UI. Certain read errors may occur when a user attempts to access a file from the file or content directory. In order to overcome this problem, it is proposed to implement a polling method in the central device (10). At fixed time intervals, such as 100ms, the player (10) sends control commands to read the status of each slot (12) of the memory card reader (11).

Description

Method for managing insertion or removal of memory card into or out of card reader and device used in said method

technical field

The present invention relates to handling data access to mass storage devices such as memory cards.

Background technique

In the field of personal computers, the serial bus communication standard is known as USB = Universal Serial Bus. Various bus standards are known. Version 1.1 of USB supports two speed modes, 12Mbit/s and 1.5Mbit/s. Version 2.0 of USB supports high-speed data transfers up to 480Mbit/s. Most of the peripheral devices of today's personal computers, such as printers, scanners, keyboards, mice, digital cameras, etc., are equipped with USB ports. The USB interface is not only used in the PC field. Today, existing products from the CE field also have a USB interface.

An example is a DVD player with a USB interface for connecting peripherals such as cameras. Instead of a camera, a memory card reader can also be connected to a DVD player. There are already universal card readers that have slots for all existing memory cards such as Memory Stick, Compact Flash, Smart Media, SD Card and MultiMediaCard.

USB compliant devices are always marked with the USB class label. A USB class describes a group of devices or interfaces with similar attributes or services. The mass storage device class is one of the USB classes.

The mass storage device class supports two main interface protocols, namely bulk-only (Bulk-Only) transfer and control/bulk/interrupt (CBI) transfer. CBI is only certified for use with full-speed floppy drives. CBI should not be used on high-speed devices or devices other than floppy disk drives. For data transfer to and from memory cards/sticks, a bulk-only transfer protocol is provided.

A USB compatible device supports a plug-and-play attribute, which is also called a life insertion (lifeinsertion) attribute. When a USB device is plugged in, there will be an interrupt generated by the USB hardware, thus notifying the USB host controller. Similarly, when a USB device is unplugged, another interrupt will be generated by the USB hardware, signaling the unplug event to the USB host controller.

Application software for DVD players equipped with a USB interface supports the USB mass storage device class using a bulk-only interface protocol. There are mainly two types of devices under this category, namely U disk (USB thumb-drive) and USB memory card reader. Since the USB stick is an independent device, it is easier to manage; if the user wishes to access the contents of another USB stick, he has to perform an unplug and plug sequence.

Unfortunately, this is not the case with USB memory card readers; with the X-In-1 memory card reader, there is no need to unplug & insert the memory card reader in order to change a new memory card. In this case, the USB host controller will not be notified of the device state change, so it does not perform a directory/file scan to collect the table of contents again (ie no refresh of the table of contents occurs).

To make matters worse, volume information (containing directories and files) is buffered on insert events, and since the player is unaware of memory card removal, this buffered information is not cleared. This means that even if a previously inserted memory card is removed from the memory card reader, the user can still navigate its directory/file listing, which is confusing and undesirable.

During playback or scanning of the memory card's directory/file information, when unable to read any data from the device, the player will panic and block with an error condition, and usually it will continue to wait until it eventually times out .

Contents of the invention

In order to overcome the above-mentioned problems, the general idea of the present invention is a method for managing the insertion or removal of a memory card into or out of a card reader, periodically scanning at least one slot of the memory card reader for the presence of a memory card, and if detected inserted card, store it in the storage section of the device.

A central device including a USB host controller implements a polling method in order to ensure detection of memory card insertion/removal.

This polling method can be interrupted during playback of files on the inserted memory card. The polling method can also be interrupted during the scanning of the contents of the memory card. In summary, it is advantageous if polling is performed in the playback and disc scan engines.

The method is an extension of the USB Mass Storage Class-Bulk Transfer Only specification.

For the device used in the method according to the invention, advantageously said device comprises sending means for periodically sending control commands via the bus connection, scanning at least one slot of a memory card reader for the presence of a memory card , and includes registration means for registering the presence of the inserted memory card in the registration part.

Further advantageous embodiments are evident from the respective dependent claims.

Other advantageous embodiments of the playback and disc scan engine are listed below:

I. During the file scanning phase: When an error occurs while reading file information from the memory card, the memory card is considered to be removed. Erases all information belonging to the memory card.

II. During playback phase: The memory card is considered to be removed when an error occurs while reading data from the memory card for playback. Erases all information belonging to the memory card.

III. During the idle phase: when the application is idle, the checksum of the memory card is checked periodically. The memory card is considered to be removed when an error occurs while reading the data used to calculate the checksum from the memory. Erases all information belonging to the memory card.

Description of drawings

Exemplary embodiments of the invention will be described in more detail with reference to the accompanying drawings, which show:

Figure 1 is a DVD player and an external memory card reader connected to each other via a USB bus connection; and

Figure 2 is a state diagram of software running in a DVD player for managing the insertion and removal of a memory card into or from a memory card reader.

Detailed ways

In FIG. 1, reference numeral 10 denotes a DVD player. An external memory card reader is indicated by reference numeral 11 . The peripheral memory card reader 11 and DVD player 10 are connected to each other through a USB bus connection.

External memory card readers are known to have multiple slots 12 for different types of memory cards. Currently, there are different types of memory cards on the market: memory sticks, multimedia cards, SD cards, smart media cards and compact flash cards. These cards come in different shapes and sizes and different types of lands. Therefore, in order to be able to handle all these cards, the card reader 11 is provided with a plurality of slots 12 of different sizes as shown in FIG. 1 .

USB uses a time-sharing serial data stream. The addressing scheme allows up to 127 devices to be connected to the bus. A multi-card reader has only one address assigned to it. There is only one active device on the bus, which is usually the PC. The active device polls all connected peripherals at a fixed interval of one millisecond. Each peripheral device responds by placing its data on the time-multiplexed bus at its allotted time within the lms frame.

In an application according to the invention with a point-to-point connection between a DVD player 10 and a card reader 11, the DVD player is configured as an active device for bus management.

In order to simplify the processing of memory card reading, it can be provided that only one memory card can be inserted into the card reader at a time.

Polling the reader at a fixed interval of 1ms does not mean that the reader puts data on the wire if the DVD player does not request a read operation. Usually a DVD player invokes a read operation of the complete file (ie selected still picture or audio file). After requesting this read operation, the reader puts its data on the wire until the complete file is transferred. When the reader is idle, there is no data to transmit after the read operation is complete.

Each USB peripheral requires its own class of drivers. As stated in the constitution clause, the USB-equipped DVD player 10 supports the USB mass storage device class with a bulk-only interface protocol. A suitable low-level driver is installed on the DVD player 10 as an integral part of its software, or the driver is purchased together with the multi-card reader 11 at the time of purchase. In this case, the user must mount the driver.

Next, the structure of the application software using the low-level driver of the card reader 11 is explained with reference to FIG. 2 .

The USB application software is a state machine with 7 states and 8 state variables. Figure 2 shows this state diagram. In Fig. 2, the different states are indicated by circles. State transitions are shown with dashed arrows. The state variables causing the transition are shown in capital letters along the corresponding dashed arrows. Next, the different states are described.

USB_Ready

This state is entered after the DVD player is powered on but no USB peripherals are connected. If a USB device is connected, the USB hardware generates an interrupt, and in the service program, generates a USB_PLUGIN message, causing a transition to the USB_Enumeration state.

USB_Enumeration

The process of bus enumeration is the activity of identifying and assigning unique addresses to devices attached to the bus. If a supported USB device (USB card reader/U disk) is detected, a USB_SUPPORTED_DEVICE_FOUND message is sent, and the state changes to USB_Library_Scanning. The user interface UI will then display the message "Scanning Files".

If an unknown USB device is detected, a USB_UNKNOWN_DEVICE_FOUND message is sent and a transition to the USB_Enumeration_Fail state is performed. The UI will output the message "There is a problem with the card".

USB_Enumeration_Fail

If the USB device is unplugged in this state, an external interrupt is triggered, a USB_READER_REMOVED message is generated, and a transition to the USB_Reay state occurs. Since the card reader is not in playback mode when this event occurs, the UI will display either a "no card" message or a "card reader disconnected" message.

USB_Lib_Scanning

When a supported multimedia file (MMF) is detected, a USB_SUPPORTED_FORMAT message will be sent and a transition to the USB_With_Supported_MMF state will be performed.

When an unsupported MMF file is detected, a USB_UNSUPPORTED_FORMAT message is sent and a transition to the USB_Without_Memory_Card state is performed.

When no memory card connected to the card reader is detected, a USB_MEMORY_CARD_REMOVED message is generated, which causes a transition to the USB_Without_Memory_Card state.

If the USB device is pulled out in the USB_Lib_Scanning state, an external interrupt is triggered, and the USB_READER_REMOVED message is sent again, and the transition to the USB_Ready state is performed. The UI will display a "No Card" message.

USB_With_Supported_MMF

If the memory card is removed in this state, a USB_MEMORY_CARD_REMOVED message is generated and the state changes to USB_Without_Memory_Card at the same time. The UI will display "No Card".

If the USB device is pulled out, an external interrupt is triggered, and a USB_READER_REMOVED message is sent, and it changes to USB_Ready. Since it is not in playback when the card reader is removed, the UI will display a "no card" message.

USB_Without_MMF

If the memory card is removed, a USB_MEMORY_CARD_REMOVED message is sent and the state changes to USB_Without_Memory_Card at the same time. The UI will display "No Card".

If the USB device is pulled out, an external interrupt will be triggered, and the USB_READER_REMOVED message will be sent again, and it will change to the USB_Ready state. The UI will display "No Card".

USB_Without_Memory_Card

If the USB device is pulled out, an external interrupt is triggered, a USB_READER_REMOVED message is sent, and a transition to the USB_Ready state is performed. The UI will display "No Card".

When a memory card is inserted and the event is detected according to the polling method of the present invention, a USB_Memory_Card_Inserted message is sent and a transition to the USB_Lib_Scanning state is performed. The UI outputs a "scanning file" message.

Polling is always performed, ie polling is performed in all the above states except the USB_Ready state. For example, polling may be performed every 100 ms, even during playback of a DVD.

Each slot 12 of the multi-card reader is checked for a change in the status of the memory card (removal of a card or insertion of a new card). For this purpose, the multi-card reader has at least one register for each slot, in which it is indicated whether a card is inserted. These registers can be read independently via USB control commands. The USB driver software for multi-card readers supports this operation. So the device is always aware of the current status and will not give the user "wrong" status information about available files. This is also the case during playback of multimedia files from an inserted card, since data reception from a memory card that has been removed is no longer expected, i.e. the device does not enter an error state.

The state variables are listed below and briefly explained:

USB_PLUGIN

This message is sent when a USB device is connected.

USB_READER_REMOVED

Whenever the USB card reader or device is disconnected from the USB port, an interrupt is triggered and a USB_READER_REMOVED message is sent.

USB_SUPPORTED_DEVICE_FOUND

This message is sent when a USB storage device (ie, a USB card reader or a USB flash drive) is successfully detected.

USB_UNKNOWN_DEVICE_FOUND

This message is sent when no USB storage device (ie USB card reader or USB flash drive) is detected.

USB_SUPPORTED_FORMAT_FOUND

This message is sent if a supported multimedia file (ie MP3/JPEG) is found in the memory card.

USB_UNSUPPORTED_FORMAT_FOUND

This message is sent if an unsupported multimedia file (ie MP3/JPEG) is found in the memory card.

USB_MEMORY_CARD_INSERTED

This message is sent when the explained USB polling method detects that a memory card is inserted.

USB_MMORY_CARD_REMOVED

This message is sent whenever the memory card is removed.

Various modifications of the described embodiments are possible and fall within the scope of the following claims. For the solution according to the invention, a multi-card reader is not necessarily required. Additionally, single card readers can also benefit from the present invention. A USB connection is not necessarily required between the DVD player and the card reader. Different bus connections can be used, such as ATA/IDE or IEEE 1394. It is not necessary for a DVD player to implement the invention. The same solution can also be used in some other CE devices like PCs including HDD recorders, STBs etc.

Claims (10)

1. A method for managing the operation of inserting or extracting a memory card into or out of a card reader (11), wherein the card reader (11) is connected to the central device (10) via a bus connection (13) without inserting the memory card or report the unplugging operation to the central device (10), It is characterized in that the central device (10) periodically scans at least one slot (12) of the memory card reader (11) for the presence of a memory card, and if an inserted card is detected, registers it in the central device (10) the registered part. 2. The method according to claim 1, wherein the card reader (11) is a peripheral device of the central device (10). 3. The method according to claim 1 or 2, wherein when the removal of the memory card is detected during the scanning operation, the file or content directory of the memory card is deleted. 4. The method according to one of claims 1 to 3, wherein an audible/visual warning message is generated for the user when removal of the memory card is detected during the scanning operation. 5. Method according to one of the preceding claims, wherein the bus connection (13) is a serial bus connection, in particular of the USB or ATA or IDE type. 6. Method according to one of the preceding claims, wherein the registered part is part of a boot sector in a memory of the central device (10). 7. A device for use in the method according to one of claims 1 to 6, comprising a bus connection (13) for connecting the device to a memory card reader (11), characterized in that the The device comprises: sending means for periodically sending control commands via said bus connection (13) for scanning at least one slot (12) of a memory card reader (11) for the presence of a memory card; and registering Means for registering the presence of the inserted memory card in the register section. 8. The apparatus according to claim 7, comprising deleting means for deleting the file information or the contents directory of the memory card stored in the memory of the apparatus when it is detected that the memory card is detached during the scanning operation. 9. A device as claimed in claim 7 or 8, wherein the registered portion is part of a boot sector in a memory of the device. 10. Device according to one of claims 7 to 9, wherein the bus part (13) is a serial bus connection, in particular of the USB or ATA or IDE type.

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