JP2009199140A - Data transfer method, data transfer program and recording medium storing data transfer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data transfer method, a data transfer program and a recording medium storing the data transfer program, reducing influence by noise without adding specific hardware. <P>SOLUTION: In a USB (Universal Serial Bus) apparatus 1 wherein a body part 3 and a USB memory 2 recording music data are connected by a USB interface, it is detected by abnormal data not prescribed as data that the electric noise is made to be applied onto a signal line of the USB interface, a USB frame wherein the abnormal data are detected is made to be retransmitted when the USB frame detected with the abnormal data is one frame or below, the USB frame detected with the abnormal data is masked to make reproduction be performed from the next USB frame when the USB frame detected with the abnormal data is not less than one frame and not more than the number of maskable frames, and resetting is performed to the USB memory 2 to perform resetup when it is more than the number of the maskable frames. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a data transfer method, a data transfer program, and a recording medium storing a data transfer program, in which data is transferred using an interface defined by a USB (Universal Serial Bus) protocol.

  In recent years, a USB memory, which is a recording medium using a semiconductor memory having an interface (USB interface) defined in the USB protocol, has been used for various purposes.

  In addition to using this type of USB memory as an external storage device such as a personal computer, for example, music data and video data can be recorded and attached to an electronic device such as a stereo device or a television equipped with a USB interface. It may be used for the purpose of reproducing music data or video data recorded in a memory.

  When noise due to the influence of electromagnetic waves of wireless communication such as static electricity or wireless LAN is applied to a signal line of a USB interface that connects a device such as a USB memory and an electronic device (host) such as a stereo device or a television set. There are problems such as a problem in the sound and video being played back, or the playback itself being stopped.

For the above-described problem, for example, a USB device described in Patent Document 1 has been proposed. The USB device described in Patent Literature 1 is initialized by resetting the USB device when the USB device runs away by the added reset circuit.
JP 2002-373036 A

  However, since the USB device described in Patent Document 1 adds hardware called a reset circuit, it is necessary to verify the increase and complexity of the hardware and the electrical adverse effects of the reset circuit itself. As a result, there was a problem of increased development costs.

  Accordingly, an object of the present invention is to provide a data transfer method, a data transfer program, and a recording medium storing the data transfer program that reduce the influence of noise without adding hardware, for example.

  In order to solve the above-mentioned problem, the data transfer method according to claim 1 is a data transfer method between a device and a host using an interface defined in the USB protocol, and is externally connected to a signal line of the interface. If abnormal data due to the influence of electrical noise applied from the device is detected and the length of the abnormal data is equal to or shorter than a predetermined first time, the abnormal data is read from the device again, When the length of the abnormal data exceeds the first time and is equal to or less than a predetermined second time, the next data of the abnormal data is read from the device, and the length of the abnormal data is the first time When the time of 2 is exceeded, a reset operation is performed to read data from the head of the device.

  7. The data transfer program according to claim 6, which is a data transfer program for causing a computer to function as data transfer means for transferring data to and from a device using an interface defined by the USB protocol, the signal line of the interface And detecting means for detecting abnormal data due to electrical noise applied from the outside, and if the length of the abnormal data is equal to or shorter than a first time, the data transfer means again receives the abnormal data. When the abnormal data is read from the device and the length of the abnormal data exceeds the first time and is equal to or shorter than the second time, the data transfer unit reads the next data of the abnormal data from the device. If the length of the abnormal data exceeds the second time, the data transfer means performs a reset operation to As control means for controlling to read data from the beginning of the scan, and characterized by causing the computer to function.

  Hereinafter, a data transfer method according to an embodiment of the present invention will be described. In the data transfer method according to an embodiment of the present invention, when the length of abnormal data due to the effect of applied electrical noise is equal to or shorter than a predetermined first time, the data is read again, If the time exceeds 1 time and is less than or equal to the predetermined second time, the next data of the data is read. If the time exceeds the time, the reset operation is performed to read the data from the top of the device. , Resend, skip (mask), reset, and operation can be changed depending on the magnitude (length) of the influence of noise, and the influence of noise can be reduced by reducing measures according to the influence of noise . In addition, noise application is detected based on whether or not the data is abnormal, and only the handling of the data is changed. This eliminates the need for additional hardware and reduces the impact of noise while reducing development costs. can do.

  In addition, data transfer from the device to the host may be performed by bulk transfer defined by the USB protocol. By doing so, it is possible to reduce the influence of noise in data transfer using bulk transfer.

  In addition, the first time and the second time may be determined in advance by the number of frames determined in the USB protocol. In this way, the first time and the second time can be measured by using a counter that simply counts the number of frames without using a special timer. Can be easily determined.

  Further, the second time may be less than the time for which the forced reset is performed in the host. By doing so, it is possible to initialize only the data transfer with the device without forcibly resetting and initializing the host.

  In addition, audio data or video data may be recorded on the device. In this way, when audio data and video data are transferred and reproduced, the influence of noise application can be reduced while continuing reproduction as much as possible.

  In the data transfer program according to the embodiment of the present invention, when the length of the abnormal data due to the influence of the applied electrical noise detected by the detection unit is equal to or less than the predetermined first time, , When the data transfer means reads the data again, and when the second time exceeds the first time and is equal to or less than the predetermined second time, the data transfer means reads the next data of the data, If this time is exceeded, the control means controls the data transfer means to perform a reset operation so that data is read from the beginning of the device. Therefore, retransmission and skipping are performed depending on the magnitude (length) of the influence of noise. (Mask), reset, and operation can be changed, and the influence of noise can be reduced by a reduction measure corresponding to the influence of noise. In addition, noise application is detected based on whether or not the data is abnormal, and only the handling of the data is changed. This eliminates the need for additional hardware and reduces the impact of noise while reducing development costs. can do.

  Further, the above-described data transfer program may be stored in a computer-readable recording medium. In this way, the data transfer program can be distributed alone as well as incorporated into the device, and version upgrades can be easily performed.

  A data transfer method according to an embodiment of the present invention will be described with reference to FIGS. A data transfer method according to an embodiment of the present invention is applied to a USB device 1 as shown in FIG. As shown in FIG. 1, the USB device 1 includes a USB memory 2 and a main body 3, and the USB memory 2 and the main body 3 are connected by an interface defined by the USB protocol.

  The USB memory 2 as a device is a recording device using a non-volatile memory such as a flash memory, and includes a connection terminal conforming to a USB interface. In this embodiment, music data encoded by MP3 (MPEG Audio Layer-3), AAC (Advanced Audio Coding), or the like is recorded in the USB memory 2. Of course, it goes without saying that the music data is not limited to encoded data.

  The main body unit 3 as a host includes a USB host unit 4, a microcomputer 5, a memory 6, a decoder 7, and an audio output terminal 8.

  The USB host unit 4 includes a connection terminal conforming to the USB interface, performs communication defined by the USB protocol with the USB memory 2 in accordance with an instruction from the microcomputer 5, reads data from the USB memory 2, and controls the USB memory 2. And so on.

  The microcomputer 5 as data transfer means, detection means, and control means is a microcomputer incorporating a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like, and controls the entire main body 3. In addition, data transfer between the USB host unit 4 and the USB memory 2 and control at the time of detecting abnormal data due to noise are performed.

  The memory 6 is a semiconductor memory that temporarily stores music data read from the USB memory 2.

  The decoder 7 reads and decodes the music data stored in the memory 6, converts it into an analog signal, and outputs it from the audio output terminal 8.

  Next, in the USB device 1 configured as described above, processing when an abnormality occurs due to noise during data transfer between the USB memory 2 and the main body 3 will be described with reference to the flowcharts of FIGS. The flowcharts shown in FIGS. 2 to 4 are constituted by programs recorded in the ROM in the microcomputer 5 and are executed by the CPU in the microcomputer 5.

  First, in step S1, the connection state with the USB device is periodically checked, and the process proceeds to step S2. In this step, the USB host 4 is made to read music data from the USB memory 2 by bulk transfer defined by the USB protocol, and when the music data is received, an ACK or NAK command is sent to the USB memory 2 in units of frames. . The ACK and NAK commands are defined in the USB protocol, and indicate that ACK has been successfully received and NAK has not been received normally.

  Next, in step S2, it is determined whether or not abnormal data has been received. If abnormal data has been received (in the case of YES), the process proceeds to step S3. If not (in the case of NO), the process returns to step S1. Abnormal data refers to the case where DP (also referred to as D +) and DM (also referred to as D-), both of which are USB interface signal lines, are in a low level state. In the USB protocol, a combination of DP and DM, which means “0” or “1” of data to be transferred, is defined, and there is no combination of DP and DM Low as data to be transferred. Therefore, when such a combination that is not possible as data is detected, it is recognized as abnormal data. In particular, when noise caused by static electricity or electromagnetic waves from wireless communication is applied to the signal line from the outside, this abnormal data often appears on the USB interface signal line as such abnormal data. By doing so, noise can be detected. That is, abnormal data due to the influence of electrical noise applied from the outside is detected.

  Next, in step S3, it is determined whether or not the abnormal data detected in step S2 is within one frame as the first time. If it is within one frame, the process proceeds to step S4. If it exceeds one frame, step S6 is performed. Proceed to The determination in this step is performed for each USB frame. That is, if abnormal data is detected even with one bit in one USB frame, it is determined that the USB frame is abnormal. Therefore, the case of exceeding one frame means whether or not two or more USB frames in which abnormal data is detected even with one bit are detected continuously. The first time is not limited to within one frame, but must be at least shorter than the second time described later.

  Next, in step S4, NAK is returned to the USB memory 2, the same one frame is requested again, and the process proceeds to step S5. That is, it requests re-transmission of the USB frame in which abnormal data is detected.

  Next, in step S5, the frame data retransmitted in response to the NAK is overwritten, changed to normal data, and the process returns to step S1. That is, the retransmitted USB frame is overwritten on the address in the memory 6 where the USB frame is written. In this way, if the noise is about one frame period, it is retransmitted and the data in the memory 6 is overwritten, so that the audio signal is not interrupted and the reproduction continues without affecting the decoding operation of the decoder 7. Is done.

  In step S6, it is determined whether or not the abnormal data detected in step S2 is the number of frames that can be masked as the second time. If the number of frames that can be masked is reached, the process proceeds to step S7 and mask processing is impossible. If the number of frames is greater (exceeds the number of frames that can be masked), the process proceeds to step S8. Masking means that USB frames that have become abnormal data are skipped without being reproduced, and the number of frames that can be masked is a predetermined number of frames. However, the predetermined number of frames is based on the specifications of the bus connecting the microcomputer 5 and the USB host 4, and the microcomputer 5 is not in a normal state such as the microcomputer 5 running out of control without bus communication. The time is shorter than the time for forcibly resetting by an interrupt or the like. In other words, if the time is set longer than the time for forcibly resetting, the microcomputer 5 is forced to be reset and playback cannot be continued, and when the microcomputer 5 itself is reset, the program of the microcomputer 5 is also initialized. Therefore, there is a possibility that it will take a recovery time, so that the processing can be performed on the program by making it shorter than the time for forcibly resetting.

  Next, in step S7, a predetermined number of frames are masked, the next SOF, Address, and StreamData are requested, and the process returns to step S1. SOF (Start Of Flame), Address, and StreamData are data included in the USB frame. That is, the frame determined to be abnormal data is not subjected to decoding processing by the decoder 7. The USB memory 2 is requested for data at the next address of the masked frame, and reproduction is continued from the data at the next address.

  In step S8, the USB host unit 4 sends a USB reset to the USB memory 2, and the process proceeds to step S9. USB reset means that both DP and DM signals are set to low level. By doing so, the operation of the USB memory 2 is initialized.

  Next, in step S9, the USB host unit 4 sends a Get Descriptor to the USB memory 2, and the process proceeds to step S10. In this step, a command for obtaining information for re-recognizing the USB memory 2 such as information for identifying the USB memory 2 stored at address 0 of the USB memory 2 is transmitted.

  Next, in step S10, the USB reset is sent again, and the process proceeds to step S10. By performing the second reset in this step, the USB memory 2 can be surely initialized.

  Next, in step S11, a USB address is allocated from the USB host unit 4 to the device (USB memory 2), Set Address is sent to the USB memory 2, and the process returns to step S1. Thus, the re-setup of the USB memory 2 is completed, and the music data reading can be resumed.

  According to the present embodiment, in the USB device 1 in which the main body unit 3 and the USB memory 2 in which music data is recorded are connected via the USB interface, electrical noise is applied to the signal line of the USB interface. Detected by abnormal data not defined as data, if the USB frame in which the abnormal data is detected is 1 frame or less, the USB frame in which the abnormal data is detected is retransmitted, and the USB frame in which the abnormal data is detected If the number exceeds the number of frames that can be masked and is less than the number of frames that can be masked, the USB frame in which abnormal data is detected is masked and reproduced from the next USB frame. By resetting and performing re-setup, the number of frames in which abnormal data is detected is increased. Flip and it is possible to carry out measures to reduce the impact of noise. Further, since the noise application is detected depending on whether or not the data is abnormal, it is not necessary to add hardware and the development cost can be reduced.

  In addition, since data transfer is performed by bulk transfer defined in the USB protocol, it is possible to reduce the influence of noise in transferring music data or the like using bulk transfer.

  Further, since the number of USB frames is used to determine the influence of noise (abnormal data length), it is only necessary to count the number of frames, and the determination can be facilitated.

  Further, by making the number of maskable frames shorter than the time required for the forced reset from the outside of the microcomputer, it is possible to continue the reproduction as much as possible and prevent the initialization of the microcomputer 5 due to noise.

  The data recorded in the USB memory 2 is not limited to music data (audio data) but may be video data. In the present invention, since masking (skipping skipping) is performed, data such as music or video that has little influence even if data is lost (sound skipping or video disturbance occurs but at least playback can be continued) is used. Can be applied if present.

  According to the embodiment described above, the following data transfer method and data transfer program can be obtained.

(Supplementary note 1) A data transfer method between the USB memory 2 and the main unit 3 using an interface defined in the USB protocol,
If abnormal data due to the effect of electrical noise applied to the interface signal line from the outside is detected and the length of the abnormal data is one frame or less, the abnormal data is read from the USB memory 2 again. If the length of abnormal data is less than the time that can be masked beyond iframe, the next data of the abnormal data is read from the USB memory 2 and the length of abnormal data exceeds the maskable time A data transfer method characterized in that data is read from the head of the USB memory 2 by performing a reset operation.

  According to this data transfer method, operations such as retransmission, skipping (masking), and reset can be changed according to the magnitude (length) of the influence of noise, so that the influence of noise can be reduced. In addition, noise application is detected based on whether or not the data is abnormal, and only the handling of the data is changed. This eliminates the need for additional hardware and reduces the impact of noise while reducing development costs. can do.

(Supplementary Note 2) A data transfer program for causing a computer to function as the microcomputer 5 that performs data transfer between the USB memory 2 and the main body 3 using an interface defined in the USB protocol,
A microcomputer 5 for detecting abnormal data due to electrical noise applied to the interface signal line from the outside;
If the length of the abnormal data is 1 frame or less, the microcomputer 5 is caused to read the abnormal data again from the USB memory 2, and the length of the abnormal data exceeds the i-frame and can be masked. In some cases, the microcomputer 5 is caused to read the next data of the abnormal data from the USB memory 2, and when the length of the abnormal data exceeds the maskable time, the microcomputer 5 is caused to perform a reset operation and the USB memory 2. A data transfer program for causing a computer to function as the microcomputer 5 that controls to read data from the head of the data.

  According to this data transfer program, it is possible to reduce the influence of noise because the operation can be changed, such as retransmission, skipping (masking), and reset, depending on the magnitude (length) of the influence of noise. In addition, noise application is detected based on whether or not the data is abnormal, and only the handling of the data is changed. This eliminates the need for additional hardware and reduces the impact of noise while reducing development costs. can do.

  In addition, the Example mentioned above only showed the typical form of this invention, and this invention is not limited to an Example. That is, various modifications can be made without departing from the scope of the present invention.

1 is a block diagram of a USB device to which a data transfer method according to an embodiment of the present invention is applied. FIG. 3 is a first part of a flowchart illustrating processing when an abnormality occurs due to noise during data transfer between the USB memory 2 and the main body unit 3 in the USB device shown in FIG. 1. FIG. 6 is a second part of a flowchart illustrating processing when an abnormality occurs due to noise during data transfer between the USB memory 2 and the main body unit 3 in the USB device illustrated in FIG. 1. FIG. 6 is a third part of a flowchart illustrating processing when abnormality occurs due to noise during data transfer between the USB memory 2 and the main body unit 3 in the USB device illustrated in FIG. 1.

Explanation of symbols

1 USB device 2 USB memory (device)
3 Main body (host)
5 Microcomputer (data transfer means, detection means, control means)

Claims (7)

A data transfer method between a device and a host using an interface defined in the USB protocol,
When abnormal data due to the influence of electrical noise applied from the outside to the signal line of the interface is detected and the length of the abnormal data is equal to or shorter than a predetermined first time, the abnormal data Is read from the device again, and when the length of the abnormal data exceeds the first time and is equal to or shorter than a predetermined second time, the next data of the abnormal data is read from the device, and the abnormal data When the data length exceeds the second time, the data transfer method is characterized in that the data is read from the head of the device by performing a reset operation.   The data transfer method according to claim 1, wherein data transfer from the device to the host is performed by bulk transfer defined by a USB protocol.   3. The data transfer method according to claim 1, wherein the first time and the second time are determined by the number of frames defined in a USB protocol.   4. The data transfer method according to claim 1, wherein the second time is less than a time during which a forced reset is performed in the host. 5.   The data transfer method according to any one of claims 1 to 3, wherein audio data or video data is recorded in the device. A data transfer program for causing a computer to function as data transfer means for transferring data to and from a device using an interface defined in the USB protocol,
Detecting means for detecting abnormal data due to electrical noise applied from the outside to the signal line of the interface;
When the length of the abnormal data is equal to or shorter than the first time, the data transfer unit is caused to read the abnormal data again from the device, and the length of the abnormal data is equal to the first time. If it is less than or equal to the second time, the data transfer means reads the next data of the abnormal data from the device, and if the length of the abnormal data exceeds the second time, A data transfer program that causes the computer to function as control means for controlling the data transfer means to perform a reset operation so as to read data from the head of the device.   A computer-readable recording medium storing the data transfer program according to claim 6.

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