KR100496506B1 - Method For Providing Extended USB Functions Using Standard UMS Communication - Google Patents

Abstract

The present invention provides only a software stack for a standard UMS communication protocol, so that a USB device can be configured relatively simply, but also various basic functions using standard UMS communication as well as various extended functions using non-standard communication can be provided through a USB interface with a host system. The present invention relates to a method for providing an extension function of a USB device using standard UMS communication. According to a method of providing an extension function of a USB device of the present invention, by providing a software protocol stack for standard UMS communication to a USB device, both standard UMS communication and non-standard communication with a host system via USB are possible, and thus, standard UMS USB devices capable of both standard and non-standard communication can be configured simply and inexpensively in software. Also, since complicated software operations are performed on the host system, the communication speed increases with the performance of the host system. There is an advantage.

Description

{Method For Providing Extended USB Functions Using Standard UMS Communication}

The present invention provides only a software stack for a standard UMS communication protocol, so that a USB device can be configured relatively simply, but also various basic functions using standard UMS communication as well as various extended functions using non-standard communication can be provided through a USB interface with a host system. The present invention relates to a method for providing an extension function of a USB device using standard UMS communication.

In the past, various peripheral devices that exchange data with a host system generally used USB interfaces. To this end, system developers first define PC drivers and communication protocols for each USB device, and provide PC manager programs using them. In addition, the user has to be inconvenient to install a PC driver and an administrator program for each USB device for each host system.

In order to solve this problem, a USB standard called USB Mass Storage Class (UMS) has been proposed in the USB Forum, and many host operating systems such as Windows 2000 or Windows XP have PC drivers installed according to the standard UMS standard. Through this, if the USB device is designed to support the USB communication of the above-mentioned standard UMS standard, it is expected that the USB device can be easily used by using a Windows application because the PC driver for the standard UMS is installed in the operating system by default.

However, the standard UMS standard provides only basic functions such as file reading, disk format, file writing, etc. among the many functions provided by the existing non-standard communication protocols, and changes the font of the USB device or upgrades the firmware of the USB device. No special extensions have been considered, such as performing special DRM operations. Therefore, a USB device that wants to use such an extension function is insufficient as a communication protocol according to the standard UMS standard, and thus a non-standard communication protocol has to be additionally provided. Thus, the software protocol configuration of the USB device becomes more complicated.

1 shows a software protocol stack of a general USB device 110 and a host system 120 according to the prior art. The illustrated software protocol stack is a communication protocol of the standard UMS standard for basic functions as described above. It is designed to support all of the non-standard communication protocols for the extension, thereby making the protocol stack of the USB device 110 very complex.

First, functionally classify the protocol stack embedded in the USB device 110, and the File System Layer, the FAT layer, and the Non-UMS Protocol Layer may be used to support non-standard communication protocols. The UMS Protocol Layer is a part for supporting a communication protocol of a standard UMS standard, and the FTL System Layer and the FTL I / O layer are parts for supporting a mass storage medium.

In addition, if the functional stack of the protocol stack embedded in the host system 120 is functionally classified, the Windows UI, the USB protocol layer, and the USB driver layer on the left side are for supporting non-standard communication protocols, and the Windows UI, file system layer, The FAT layer, the UMS protocol layer, and the USB driver layer are parts for supporting the communication protocol of the standard UMS standard.

As described above, in the software protocol stack according to the USB communication method of the prior art, not only the communication protocol according to the standard UMS standard but also the non-standard communication protocol for the extension function must be installed together, so that there are quite a lot of software modules in the USB device 110. There is a problem that must be included, in particular, since the file system layer and the FAT layer are very complicated, the operation of building them in the USB device 110 takes considerable development time and the operation speed of the USB device 110 is also significantly slowed down. There is a problem.

Accordingly, the present invention provides a USB device with only a software stack for a standard UMS communication protocol, but also supports various extended functions using non-standard communication as well as basic functions using standard UMS communication through a USB interface with a host system. Its purpose is to provide a method for providing an extension function of a USB device that can easily configure a USB device.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

2 is a diagram illustrating a software protocol stack of the USB device 210 and the host system 220 according to the extended function providing method of the USB device of the present invention. First, looking at the protocol stack embedded in the USB device 210, the UMS protocol layer is provided to support the communication protocol of the standard UMS standard, and the FTL system layer and FTL I / O layer are provided to support mass storage media. On the other hand, it can be seen that the USB device 210 of FIG. 2 is not provided with a communication protocol layer at all to support the non-standard communication protocol.

In addition, when looking at the protocol stack built into the host system 220, the Windows UI, file system layer, FAT layer, UMS protocol layer, and USB driver layer on the right side are provided to support the communication protocol of the standard UMS standard. The Windows UI, file system layer, FAT layer, USB protocol layer and USB driver layer on the left are provided to support the protocol. According to the preferred embodiment of the present invention shown in FIG. 2, the host system 220 supporting the extended USB communication method is provided with a full set of software protocol stacks for the standard UMS standard communication protocol and the non-standard communication protocol.

Compared with the related art of FIG. 1, in the software protocol stack according to the present invention shown in FIG. 2, the USB communication related program installed in the USB device 210 only needs to support a standard UMS protocol. As described above, the USB communication program to be installed at 220) needs to have a full set of software protocol stacks, particularly, a file system layer and a FAT layer corresponding to the non-standard communication protocol, for the standard UMS standard communication protocol and the non-standard communication protocol. It gets complicated.

However, the host system 220 has a more convenient program development environment such as a development tool than the USB device 210, and the host system 220 has a superior program operating environment such as processing performance or available memory. It doesn't matter if the communication program gets more complicated. In addition, the USB communication speed between the USB device 210 and the host system 220 may increase in accordance with the performance improvement of the host system 220 in the future.

3 is a diagram showing the field configuration (310, 320, 330) of the command packet and the ACK packet in accordance with the standard UMS standard, CBW field configuration 310 and CSW field configuration 330 is a UMS-related standard of the USB Forum, Universal Serial Bus Mass Storage Class-Bulk Only Transport, Revision 1.0, September 31, 1999, pp. 13-15, CBW command block field configuration 320 is a UMS-related standard of the USB Forum, Universal Serial Bus Mass Storage Class-UFI Command Specification, Revision 1.0, December 14, 1998, pp. 12-14. For the matters that are not described in the protocol operation and packet configuration according to the standard UMS standard, refer to the UMS related standard provided by the USB forum.

First, the host system 120, 220 briefly describes the CBW field configuration 310, which is a kind of command packet transmitted to the USB devices 110, 210 according to the communication protocol of the standard UMS standard, the dCBWSignature field is fixed at 0x43425355. It indicates that the data packet is a command block wrapper packet according to the standard UMS standard. The dCBWTag field is used to indicate a combination of a CBW packet and a CSW packet pair. The CBWCB field is a CBW command block. Field contains details of a command sent by the USB devices 110 and 210.

Subsequently, the CBW command block field configuration 320 will be briefly described, and the Operation Code field, which is a command identification code, indicates the type of operation that the USB device 110 or 210 should perform, for example, reading a file, formatting a disk, writing a file, or the like. The contents of the following fields are defined according to the type of operation according to the Operation Code field. In this specification, as described above, the UMS-related standard provided by the USB forum is referred to.

Next, the CSW field configuration 330, which is an ACK packet provided by the USB devices 110 and 210 in response to the CBW command packet 310, is briefly described. The dCSWSignature field has a fixed value of 0x53425355. Indicates that this is a Command Status Wrapper packet according to the standard UMS standard, the dCSWTag field indicates the pair combination with the CBW packet by using the same value as the dCBWTag field of the corresponding CBW packet, and the bCSWStatus field indicates Indicates whether the operation according to the Operation Code field was successful.

4 is a diagram illustrating a general UMS flow used in a method for providing an extension function of a USB device of the present invention. First, the user selects a desired specific command (ST410), which may be a basic function that was conventionally provided using standard UMS communication, or various extended functions implemented using a separate non-standard communication. . Subsequently, it is determined whether the specific command is an available command (ST420), and the determining step ST420 is optional, for example, whether the command is available in the current operation mode of the USB device 210. Judgment can be made based on other criteria.

Subsequently, the manager program of the host system 220 generates a command packet, that is, a CBW packet 310 so as to be compatible with the field format of the communication protocol of the standard UMS standard described above with reference to FIG. 3 in response to the selected command (ST430). The CBW packet 310 is transmitted to the target USB device 210 (ST440). In the CBW packet 310, each field of the CBW command block 320, in particular, an operation code field, which is a command identification code, is set corresponding to the selected specific command. Subsequently, a process of transmitting / receiving a series of data packets between the USB device 210 and the host system 220 (ST450) is performed. For example, file data, control data, font data, Assume firmware code data and the like.

In setting the value of each field of the CBW command block 320, when the value of the command identification code is a value defined in the standard UMS standard, it provides a "basic function" and is less than or equal to the operation code in the CBW command block 320. The field of is set as specified in the standard UMS standard. On the other hand, when the value of the command identification code is a value not defined in the standard UMS standard, the "extended function" is provided according to the present invention. In the CBW command block 320, the field below the operation code is separately defined by the designer of the product. It is set according to one rule. However, the separate rule applied in providing the "expansion function" is commonly applied to the host system 220 and the USB device 210 in the present invention, so there is no communication problem.

Subsequently, the USB device 210 generates a CSW packet 330 and transmits it to the host system 220 so as to be compatible with the field format of the communication protocol of the standard UMS standard described above with reference to FIG. 3 as a kind of ACK packet. The host system 220 may determine whether a specific operation corresponding to the command identification code Operation Code was successfully performed in the USB device 210, and accordingly, the host system 220 may provide a user with a display screen of the host system 220. Information about whether the specific command succeeds can be provided.

Although not shown in FIG. 4, a step of selectively receiving a specific device operation of the USB device 210 from a user may be added before or after step ST460. For example, in the case of the firmware upgrade operation, when a transmission / reception operation for the firmware code data is performed, whether or not a valid firmware code data is received on the screen of the USB device 210 is displayed, and then the display waits for a start input for the firmware upgrade. A screen is provided, and when the user inputs a firmware upgrade command through a button input, the USB device 210 may be configured to start the firmware upgrade. Of course, these steps may not be included and the firmware upgrade may be configured as soon as the transmission and reception of the firmware code data is completed.

5 is a diagram illustrating a method of changing a font of a USB device by using the method for providing an extension function of the USB device of the present invention. The illustrated font change function is an extended function provided by the present invention without being included in the basic function of the standard UMS standard, but the interface between the manager program 620 and the device firmware 610 may be made by the standard UMS communication protocol. Designed. Since the font change command is an extended function, a code value not defined in the standard UMS standard is used in an operation code field which is a command identification code of the CBW command block 320.

First, a CBW packet designating a font erasing area from the manager program 620 is transmitted to the device firmware 610 (ST610). In this case, it is possible to change the font erasing area so that one of a plurality of fonts supported by the USB device 210 can be changed, only some data of the current fonts can be changed, or the entire font area can be erased. . When the device firmware 610 receives the CBW packet designating the font erasing area (ST615), it first erases the font data from the area designated in the CBW packet, and transmits a CSW packet, which is a kind of ACK packet, in response to the erasure result (ST620). )do. Upon receiving the CSW packet (ST625), the manager program 620 parses an internal field, for example, a bCSWStatus field, to determine whether the font data erasing operation of the designated area is successful, and determines whether to retry in response thereto.

After erasing the font area of the USB device 210, the manager program 620 transmits a CBW packet for setting an environment for transferring the font data to be recorded (ST630), and the device firmware 610 sends the CBW packet. Receive (ST635) to set the reception environment of the font data and wait for the reception of the data. In the standard UMS communication, data transmission is performed in units of pages, and as shown, font data is typically of a considerable size, so font data is divided into several packets, and the administrator program 621 transmits the data in several times. The device firmware 610 receives them several times and then recombines them.

Meanwhile, the device firmware 610 records the received font data in the erased font area. In some implementations, the device firmware 610 may record the corresponding font data in the erased font area whenever each font data packet is received. Alternatively, the entire font data may be recombined and then recorded in the erased font area. The device firmware 610 records the received font data in the erased font area and then transmits a CSW packet, which is a kind of ACK packet, in response to the result (ST640), and the manager program 620 receives the CSW packet to receive the packet. Parsing the internal field of to determine whether it is successful, and whether or not to retry accordingly. Subsequently, the device firmware 610 sets the display screen of the USB device 210 using the received font data. (Not shown)

In order to provide the font changing function shown in FIG. 5, the manager program 620 transmits font data by performing a two-step operation, that is, a first operation of erasing the font area of the USB device 210 and font data to the erased font area. A second operation of recording is performed, and it is also possible to assign a separate operation code to each of these operations, or the command identification code can be one but the other field of the CBW command block is replaced by a subfunction field. It is also possible to specify the first operation and the second operation separately by setting a separate sub function field value.

6 is a diagram illustrating a method of upgrading firmware of a USB device by using the method for providing an extension function of the USB device of the present invention. The firmware upgrade function is also an extension provided by the present invention without being included in the basic functions of the standard UMS standard. However, the firmware upgrade function is designed such that an interface between the manager program 720 and the device firmware 710 can be made by the standard UMS communication protocol. . Since the firmware upgrade command is also an extension function, a code value not defined in the standard UMS standard is used in the Operation Code field of the CBW command block 320.

First, the manager program 720 generates and transmits a CBW packet specifying a firmware upgrade operation according to the extension function (ST710), and the device firmware 710 of the USB device 210 receives the CBW packet (ST715). The system operation mode then switches to the firmware upgrade mode. Subsequently, the manager program 720 transmits an information packet including information necessary for downloading the download program DN_PGM to perform the download operation of firmware code data to the device firmware 710 (ST720), and the device firmware 710. ) Sets the environment for downloading the download program by receiving and parsing the DN_PGM information packet (ST725).

Subsequently, the download program DN_PGM is transferred to the device firmware 710 through a series of data packet transmissions and receptions between the manager program 720 and the device firmware 710. While the data transmission is performed in units of pages, the code size of the download program DN_PGM will exceed one page, so that a plurality of DN_PGM packets are transmitted from the manager program 720. Preferably, the device firmware 710 copies the data to the internal memory of the USB device 210 when each DN_PGM data packet is received, and combines the respective data when all data packets have been transmitted and received. The reconstructed download program DN_PGM is preferably executed in the internal memory of the USB device 210.

Subsequently, the manager program 720 transmits a code information packet including various types of information to be referred to by the download program in transmission and reception of firmware code data (ST730), and the device firmware 710 receives the code information packet ( ST735) to obtain and check the included information from the code information packet. If such various kinds of information are included in the aforementioned DN_PGM information packet, the process of transmitting / receiving code information packets ST730 and ST735 may be deleted. Then, the device firmware 710 transmits the CSW packet corresponding to the above-described CBW packet (ST740), and after receiving the CSW packet (ST745), the manager program 720 parses an internal field to obtain information of the firmware code data. Determines whether the was successfully delivered and whether or not to retry.

Subsequently, firmware code data is transmitted and received between the manager program 720 and the device firmware 710 (ST750, ST755), and the USB device 210 performs an operation of replacing the firmware using the received firmware code data. In order to replace the firmware, the firmware code existing in a firmware memory area such as a flash memory or an EEPROM is erased, and the received firmware code data is recorded in the firmware memory area. Preferably, the recorded firmware code data is verified.

On the other hand, when the firmware code data is delivered in a plurality of data packets, when each data packet is received, the device firmware 710 transmits a CSW packet (ST760), and the manager program 720 receives the CSW packet ( ST765) and parse to determine whether to send the next packet or retry transmission of this packet. The data transmitted and received between the manager program 720 and the device firmware 710 as the firmware code data is preferably unchangeable data.

The manager program 720 and the device firmware 710 may determine whether transmission / reception of the firmware code data is completed based on the code information. After rebooting (ST770-1), the upgraded firmware code data is used, and in the manager program 720, the firmware download program ends (ST770-2).

The download program DN_PGM is a program downloaded from the host system 220 and executed on the USB device 210. The download operation of the firmware code data to be performed in the future, the loading location of the firmware code, and the recording and erasing method for the flash memory are performed. Etc. to enable the designer of the USB device 210 to perform the desired manner. That is, since the download program (DN_PGM) is provided by the design company of the USB device 210, DN_PGM for the USB device 210 after the DN_PGM is responsible for the download operation, the loading operation, and the installation of the actual firmware code data Optimum design is to provide the user with the USB device 210 or over the Internet. On the other hand, since the USB device 210 according to the present invention is installed a software stack for standard UMS communication, the DN_PGM receives the firmware code data through standard UMS communication.

Meanwhile, in order for the USB device firmware 610 or 710 to provide a specific extension function as described above with reference to FIGS. 5 and 6, the lowest communication layer conforms to a standard UMS standard but a non-standard operation must be performed in a higher layer. do. On the other hand, in order to provide the basic functions such as file reading, disk format, file writing, etc. by the USB device firmware 610 and 710, the lowest communication layer and more layers all operate according to the standard UMS standard. As such, depending on the situation, the USB device firmware 610 or 710 switches the operation according to the standard UMS standard and the non-standard operation, and before and after the important information of the device firmware 610 and 710, for example, Vendor_ID, Product_ID, Interface class, It may be implemented so that values of Interface subclass, Interface protocol, etc. are changed.

In order to facilitate the switching, it is preferable that the user recognizes whether the basic function or the extended function is set when the user commands a specific function through the menu of the USB device 210, and also preferably. When a user commands a specific function through the manager programs 620 and 720, whether the basic function or the extended function is recognized and set using the initial CBW packet can be set.

According to the method of providing an extension function of a USB device of the present invention, by providing a protocol stack for standard UMS communication to a USB device, it is possible to support both standard UMS communication and non-standard communication through a USB interface with a host system. USB devices capable of supporting both UMS and non-standard communications can be configured simply and inexpensively in software, and they do not need to design non-standard communication protocols for each USB product, making product design simpler and more complex. Since the work is performed in the host system, the communication speed increases with the performance of the host system.

1 is a diagram illustrating a software protocol stack according to the prior art USB communication method.

2 is a diagram illustrating a software protocol stack in accordance with a method for providing an extension function of a USB device of the present invention.

3 is a diagram showing field configurations of a command packet and an ACK packet according to the standard UMS standard.

4 is a diagram illustrating a general UMS flow used in a method for providing an extension function of a USB device of the present invention.

5 is a diagram illustrating a method of changing a font of a USB device by using the method for providing an extension function of the USB device of the present invention.

6 is a diagram illustrating a method of upgrading firmware of a USB device by using the method for providing an extension function of the USB device of the present invention.

<Explanation of symbols for the main parts of the drawings>

210: USB device

220: host system

310: CBW field configuration

320: CBW command block field configuration

330: CSW field configuration

610, 710: device firmware

620, 720: manager program

Claims (9)

A method for providing an extension function of a USB device using standard UMS communication, the method comprising: receiving a first CBW packet specifying a font erasing area from an administrator program; Parsing the first CBW packet and deleting font data corresponding to the designated area; Transmitting a first CSW packet to the manager program indicating a result of the font data erasing operation corresponding to the first CBW packet; Receiving a second CBW packet for setting a transfer environment of recording target font data from the manager program; Parsing the second CBW packet; Setting a reception environment of the record target font data and waiting for reception of the font data from the manager program; Receiving at least one data packet including font data in units of pages from the manager program and recording font data included in the at least one data packet in the font erasing area; Transmitting a second CSW packet to the manager program indicating a result of the font data recording operation corresponding to the second CBW packet; And setting a display screen of the USB device by using the received font data. The method of claim 1, wherein the receiving and recording the font data from the manager program comprises: a a step of receiving a data packet including font data in page units from the manager program; B) parsing the data packet to obtain the included font data; C) recording the obtained font data in order in the font erasing area; And determining whether the reception of the font data has been completed based on the set reception environment, and if the completion of the font data is not completed, proceeding to step a). Way. The method of claim 1, wherein the receiving and recording the font data from the manager program comprises: a a step of receiving a data packet including font data in page units from the manager program; Determining whether the reception of the font data has been completed based on the set reception environment, and if not, proceeding to step a; C) recombining the received one or more font data when the reception of the font data is completed; And d) recording the recombined font data into the font erasing area. A method for providing an extension function of a USB device using standard UMS communication, the method comprising: receiving a first CBW packet specifying a firmware upgrade operation from an administrator program; Parsing the first CBW packet and switching an operation mode to a firmware upgrade mode; Receiving an information packet for configuration of a firmware upgrade from the manager program; Parsing the information packet to set a delivery environment of the DN_PGM; Receiving one or more DN_PGM packets including DN_PGM data in page units from the manager program and reconfiguring the DN_PGM from the DN_PGM data; Executing the reconstructed DN_PGM on internal memory; Transmitting a CSW packet indicating a result of the downloading and executing operation of the DN_PGM to the manager program; Receiving at least one data packet including firmware code data in units of pages from the manager program; Replacing firmware code of the USB device with firmware code data included in the one or more data packets; And rebooting the USB device. The method of claim 4, further comprising: receiving a code information packet for setting a delivery environment of the firmware code data from the manager program; And parsing the code information packet and setting, by the DN_PGM, a delivery environment of the firmware code data. 5. The method of claim 4, wherein the firmware code data is unmodifiable data. The method of claim 1, further comprising: receiving a command for the extension function from a user of the USB device; And changing, by the device firmware of the USB device, the identifier information used in the standard UMS communication in response to the command provision. The extended function of claim 1 or 4, further comprising: changing, by the device firmware of the USB device, identifier information used in the standard UMS communication in response to the first CBW packet. How to Provide. A computer-readable information recording medium having recorded thereon a program for implementing a method for providing an extension function of a USB device using the standard UMS communication according to claim 1.