JP2978765B2 - CDROM decoding device and CDROM decoded data transfer method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CDROM decoding device, and more particularly to a CD provided in a personal computer or the like and having a function of transferring decoded CDROM data.
The present invention relates to a ROM decoding device and a CDROM decoded data transfer method.

[0002]

2. Description of the Related Art Due to their large capacity, compactness, and ease of handling, CDROMs have become popular as large-capacity fixed storage media, and recent personal computers have been using CDROs for reading data from CDROMs.
An M drive / decoding device (hereinafter referred to as a CDROM decoding device) is becoming standard equipment.

A conventional CDROM decoding apparatus of this type decodes serial data supplied from a CDROM drive one frame at a time, and transfers the decoded data after completion of decoding to a transfer destination host for each frame. In this case, the decoding operation cannot be started until the data input for one frame is completed, and the transfer of the decoded data to the transfer destination host is performed after the input serial data becomes the data of the next frame. Therefore, C
There is a difference of two frames between the data of the frame being read by the pickup of the DROM drive and the data of the frame being transferred to the transfer destination host. If data transfer is interrupted due to a buffer overflow or the like at the transfer destination host during the data transfer for each frame, a CDROM drive seek is required to resume the data transfer.

Referring to FIG. 6, which shows a block diagram of a conventional CDROM decoding apparatus of this type, a conventional CDRO decoding apparatus is shown.
The M decoding device includes: a CD ROM drive 1 for driving a CD ROM in response to the supply of a drive signal DC and outputting read data as serial data DS;
A decoder 200 that decodes the serial data DS supplied from the M drive 1, transfers the transfer data DT for each frame of the decoded data, and transfers the data to the transfer destination host 400; a decoding memory 3 that temporarily stores the decoded data; A transfer host DT for receiving the transfer data DT and using the data, and a data bus 5 for transferring the transfer data DT.

[0005] A decoder 200 decodes serial data DS and outputs decoded data DD.
And the decoded data DD are transferred in units of frames.
And a decode data transfer (DMA) unit 22 for transferring to the host 400 via the bus 5 as T.

Next, the operation of the conventional CDROM decoding apparatus will be described with reference to FIG. 6 and FIG. 7 which is a flowchart showing a transfer resuming procedure, that is, a decode data transfer method. First, the serial data supplied from the CDROM drive 1 will be described. The decoder 200 decodes the DS by the decoding unit 21 and outputs decoded data DD. The DMA section 22 transfers the decoded data DD as transfer data DT for each frame unit to the transfer destination host 400 via the data bus 5.

When the host 400 cannot receive data due to buffer overflow or data processing, that is, a data transfer interruption factor occurs (step P1).
Therefore, the flow of data on the data bus 5 stops. However, since there is no signal indicating the interruption of the output, if the input of the serial data DS does not become the head of the next frame of the frame being read at the time of the above-mentioned transfer interruption, the existence of untransferred data cannot be known. Cannot determine that the data transfer has been interrupted. On the other hand, host 40
0 recognizes the data transfer interruption by the status signal SR (step P2) of the decoder 200, and then issues a stop command to the decoder 200 by the CDROM decoder control signal CR (step P3). next,
After the host 400 itself can resume the data transfer, the address value of the interrupted frame is reset in the decoder 200 by the CDROM decoder control signal CR (step P5), and the seek command is sent to the CDROM drive 1 by the CDROM drive signal DC. (Step P6), and re-read (Step P7, Step P8) is started.

Further, even when the host 400 forcibly stops the decoder 200 at the time of the occurrence of the data transfer interruption factor, the data frame being transferred by the decoder 200 and the data being read from the CDROM drive 1 are being read at that time. There is a two-frame difference between the two frames, and the already-read frame becomes invalid when the decoder 200 is stopped, so that re-reading is required, and thus seek is required.

Next, referring to FIG. 8 which schematically shows the operation timing of each signal in a time chart, a conventional CDROM
Explaining the timing relationship of the operation of the decoding device, the host process H of the normal transfer processes the end of the transfer of the transfer data DT (T1, T4) and the end of the decode (T2, T5). At this time, when a data transfer interruption factor occurs during the transfer (T7), as described above, the host 4
Since 00 has no means to notify the decoder 200 of the data interruption, the decoder 200 cannot determine the occurrence of the interruption of the data transfer until the head of the next frame (here, the (n + 2) -th frame) is found (T9). At time T9, the decoder 200 determines that the transfer has been interrupted because untransferred data remains, and notifies the host 400 of the transfer interrupt status with the status signal SR indicating the status of the CDROM. The host 400 receives the status signal SR and instructs the decoder 200 to stop (T10).
Is issued to the CDROM drive 1 by the CDROM drive control signal DC (T11).

When the data transfer becomes resumable, the host 400 instructs the decoder 200 to reread the frame in which the data transfer was interrupted (transfer interrupted frame).
The restart is performed by the DROM decoder control signal CR (T12). Further, the pickup of the CDROM drive 1 has to perform a seek since the frame to be read has already been read once. For this reason, the host 400 issues a command to the CDROM drive 1 to seek the pickup to the transfer interrupted frame (here, the (n-1) th frame) as the CDROM drive control signal DC (T13). In this case, when the error status is indicated by the decoder 200, since the pickup of the CDROM drive 1 has advanced ahead of the target frame, an operation of returning the pickup is required, and therefore, the seek time of about 500 ms is required. Will occur.

When the above-described seek is completed and the decoder 200 finds the head of the designated frame, the process returns to the normal transfer process. The read frame data is decoded and transferred to the host 400 for two frames thereafter. (Approximately 27 ms at standard speed).

[0012]

The conventional CDR described above.
In the OM decoding device, since the data transfer interruption recognizing means has only an error that occurs due to the presence of untransferred data at the time of input of the head data of the next frame, any data transfer stop factor occurs in the data transfer destination. However, since the interruption of data output cannot be recognized until the data of the next frame is input from the CDROM drive, the data input cannot be stopped.

Further, when the input of the CDROM decoder is stopped, the output is also stopped, and the remaining data in the memory becomes invalid, so that the data already read and undergoing the decoding process becomes invalid. If the input of the CDROM decoder is forcibly stopped on the side, it is necessary to re-read the data being read, and if an error status occurs, the CDR
Since the pickup of the OM drive is ahead of the target frame, there is a disadvantage that a seek time for returning the pickup position is required.

[0014]

According to the present invention, there is provided a CD-ROM decoding apparatus which responds to a drive signal by supplying a CD-ROM.
CDROM drive comprising: a CD-ROM drive for driving and outputting read data as serial data; and a decoding means for decoding the serial data to generate decoded data and transferring the decoded data to a host device as transfer data in frame units. In the device, the host device may cause a transfer interruption of transfer data to occur.
Generates a transfer interrupt signal to notify the occurrence of this transfer interrupt.
Data buffer for temporarily storing the transfer data.
In response to the occurrence of the transfer interruption factor including
Activating the transfer interrupt signal and responding to the disappearance of the factor
This transfer interruption signal is deactivated, and the decoding means
Wherein a decoding unit which serial data by decoding to generate the decoded data, and a data transfer unit which generates the transfer data in response to the supply of the decoded data, before
Activating the transfer interruption signal supplied from the host device
Responsive to the generated data retransmission control for controlling to start from the frame of the transfer break retransfer of the transferred data in response to the deactivation of the transfer interrupt signal to stop the input of the serial data in And a unit.

Further, according to the CDROM decoded data transfer method of the present invention, data read from a CDROM drive is output as serial data, the serial data is decoded to generate decoded data, and the decoded data is transferred for each frame unit. In a CDROM decoded data transfer method for transferring data to a host device,
Overflow of data buffer for temporarily storing the transfer data
Activating a transfer interruption signal indicating the transfer interruption in response to occurrence of the transfer interruption factor including a flow, and activating the transfer control signal in response to the activation of the transfer interruption signal.
Stopping the output of the serial data to the M drive; waiting for resumption of retransfer of the transfer data due to disappearance of the cause of the transfer interruption; and suspending the transfer in response to the disappearance of the cause of the transfer interruption. The method includes a step of deactivating a signal, a step of waiting for transfer of one frame of the transfer data, and a step of restarting the CDROM drive to output the serial data.

[0016]

Next, an embodiment of the present invention will be described with reference to FIG.
Referring to FIG. 1 in which the same components as those of FIG. 1 are denoted by the same characters and similarly denoted by blocks, the CDROM decoding apparatus of the present embodiment shown in FIG. And a data bus 5, a decoder 2 having a data retransfer control unit 23 in addition to a decoder unit 21 and a decoded data transfer (DMA) unit 22 which are common to the related art instead of the decoder 200, and a host And a host for generating a data transfer interruption signal OVF and supplying the data transfer interruption signal to the decoder when the data transfer is interrupted in place of the host.

Referring to FIG. 2 showing the details of the decoder 2 in blocks, the data re-transfer control unit 23 includes an address reset block 231 for resetting a DMA transfer address.
A counter clear block 232 for clearing a DMA transfer internal counter of the DMA unit 22 and a DM in response to activation of a data transfer interruption signal OVF from the host 4.
A transfer stop / restart control block 233 for stopping the DMA transfer to the A unit 22, and an input stop for stopping the input of the serial data DS in response to the supply of the input end report signal ER of the currently input frame from the decoding unit 21. Signal HI
And a data input control block 234 that outputs

Next, the operation of the present embodiment will be described with reference to FIGS. 1 and 2 and FIGS. 3 and 4 which are flowcharts showing the transfer restart procedure of each of the host 4 and the decoder 2, that is, the decode data transfer method. First, as in the conventional case, the decoder 2 decodes the serial data DS supplied from the CDROM drive 1 by the decoding unit 21 and outputs the decoded data DD. The DMA unit 22 transfers the decoded data DD as transfer data DT for each frame to the transfer destination host 4 via the data bus 5.

Here, the main control signals used in the present embodiment will be described. The data transfer request signal DMQ and the data transfer response signal DMK, which constitute a handshake signal for data transfer between the decoder 2 and the host 4, are described below. , A data transfer interruption signal OVF indicating interruption of data transfer, a CDROM status signal SR indicating the status of the decoder 2, a decode control signal CR,
And a drive control signal DC for controlling the ROM drive.

Next, when the interruption of the transfer of the data D occurs, the host 4 determines when the interruption factor occurs (step S1).
Then, the data transfer interruption signal OVF is activated, and the decoder 2 recognizes this activation (step S2).
Step S21). Also, a pause command is issued to the CDROM drive 1 by the CDROM drive control signal DC so that a pause is applied after the currently read frame is read (step S3). The data retransfer control unit 23 stops the data transfer of the DMA unit 22 in response to the activation of the data transfer interruption signal OVF (step S22), and completes the input of the serial data DS of the frame currently being input from the CDROM drive 1. At this point, the input of the serial data DS is stopped (step S23). When the transfer of the data D can be resumed (step S4), the host 4 inactivates the data transfer interruption signal OVF (step S5), and waits for the data transfer completion status SR from the decoder 2 (step S6). ). The data retransfer controller 23 controls the DMA 22 in response to the deactivation of the data transfer interruption signal OVF (step S25), and transfers the transfer data DT corresponding to the transfer interrupted frame from the beginning (step S2).
6). When the transfer is completed, the input from the CDROM drive 1 is enabled (step S27), and the transfer is indicated by sending a status signal SR to the host 4 (step S28). The host 4 responds to the supply of the end status SR (YES in step S6), and
A pause release command is issued to the drive 1 by the CDROM drive control signal DC (step S7), and the process returns to the normal data transfer process (steps S8 and S2).
9).

Referring to FIG. 2 again, the internal operation of the decoder 2 will be described in detail. When the host 4 activates the data transfer suspension signal OVF, the transfer stop / restart control block 233 of the data retransfer control unit 23 transfers the data. The stop signal HH is supplied to the DMA unit 22 to stop the DMA transfer. Further, the counter clear block 232 supplies a clear signal RC to the DMA unit 22 to clear the internal counter for DMA transfer. Data input control block 234
Responds to the supply of the input end report signal ER of the currently input frame from the decoding unit 21 in response to the input stop signal HI.
To the decoding unit 21 to stop the input of the serial data DS.

When the data transfer interruption signal OVF is deactivated, the address resetting block 231 reads the transfer start address AT stored from the DMA 22 at the start of transfer of each frame, and reads the transfer start address AT from the DMA 22 and issues a DMA reset signal RA.
Set to. The transfer stop / resume control block 233 outputs a signal H
H is supplied to the DMA unit 22 to restart the DMA transfer. The data input control block 234 supplies the input control signal HI to the decoding unit 21 and outputs the serial data DS to the decoding unit.
Resumes input.

Next, the operation timing of each signal is schematically shown in a time chart with reference to FIG.
The timing relationship of the operation of the DROM decoding device will be described.
The end of transfer of T (T1, T4, T22, T25) and the end of decoding (T2, T5, T23, T26) are processed. At this time, when a data transfer interruption factor occurs during the transfer (T7), the host 4 activates the data transfer interruption signal OVF at that time (T7). CD at the same time
When a pause command is issued to the ROM drive 1 and the input of the serial data DS of the frame being input is completed, the CD
The ROM drive 1 is paused (T11). When the decoding of the frame being decoded is completed (T8), the decoding operation is temporarily stopped because the input of the data DS is stopped.

When the data transfer can be resumed, the host 4 inactivates the data transfer interruption signal OVF (T20). In response to the deactivation of the data transfer suspension signal OVF, the decoder 2 retransfers the data of the suspended frame from the beginning. The data retransfer control unit 23 responds to the confirmation of the end of the transfer (T18)
The pause of the drive 1 is released (T12), and the process returns to the normal transfer process from the frame next to the frame for which input has been completed.

As described above, the CD of the present embodiment
Since the ROM decoding device transfers the input serial data taken in the decoder in response to the activation of the data transfer interruption signal line without invalidating the input serial data, it is not necessary to newly read the same serial data from the CDROM drive. Since the host can control the CDROM drive in advance, the drive status at the time of data transfer interruption can be maintained.
It is only necessary to release the holding state of the OM drive, and no seek operation is required.
It is possible to reduce the reading time for second + 2 frames (about 27 msec at standard speed).

[0026]

As described above, the CDRO of the present invention is
The M decoding device and the CD ROM decoded data transfer method are characterized in that the host detects when the data transfer is interrupted and generates a data transfer interrupt signal, and the decoder responds to the supply of the data transfer interrupt signal to input serial data. And the retransmission control means that controls retransmission when the decoding data can be retransmitted is stopped, so that the transfer destination host can easily control the data retransmission and seek time. Since it becomes unnecessary, there is an effect that the transfer time can be shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a CDROM decoding device of the present invention.

FIG. 2 is a block diagram showing a configuration of the decoder of FIG.

FIG. 3 is a flowchart showing processing of a host in a CDROM decoded data transfer method according to the embodiment.

FIG. 4 is a flowchart showing the operation of the decoder in the CDROM decoded data transfer method of the present embodiment.

FIG. 5 is a time chart showing an example of a retransfer operation in the CDROM decoding device of the present embodiment.

FIG. 6 is a block diagram showing an example of a conventional CDROM decoding device.

FIG. 7 is a flowchart showing processing in a conventional CDROM decoded data transfer method.

FIG. 8 is a time chart showing an example of a retransfer operation in a conventional CDROM decoding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CDROM drive 2,200 decoder 3 Decoding memory 4,400 Host 5 Data bus 21 Decoding unit 22 Decoded data transfer (DMA) unit 23 Data retransfer control unit 231 Address reset block 232 Counter clear block 233 Transfer stop / restart control block 234 Data input control block

Claims (4)

(57) [Claims] A CDRO is provided in response to a supply of a drive signal.
A CDROM drive for driving M and outputting read data as serial data; and a CDROM comprising: decoding means for decoding the serial data to generate decoded data and transferring the decoded data to the host device as transfer data in frame units. In the decoding device, the host device may determine that the transfer of the transfer data has been interrupted.
Generates a transfer interrupt signal to notify the transfer
Overflow of data buffer for temporarily storing the transfer data
In response to the occurrence of the transfer interruption factor including the flow, the
Activates the transfer interrupt signal and responds to
A decoding unit that deactivates a transfer interruption signal, the decoding unit decodes the serial data to generate the decoded data, and a data transfer unit that generates the transfer data in response to the supply of the decoded data. Activation of the transfer interruption signal supplied from the host device
Response to response to data retransmission be controlled so as to start the re-transfer of the transferred data from the generated frame of the transfer interruption to deactivation of the transfer interrupt signal to stop the input of the serial data of A CDROM decoding device, comprising: a control unit. 2. The data retransfer control unit instructs to stop inputting the serial data in response to activation of a transfer interruption signal for notifying occurrence of the transfer interruption, and instructs the transfer interruption signal to be inactive. Data input control means for instructing restart of the input in response thereto; transfer stop / restart control means for controlling transfer stop and transfer restart of the transfer data in response to activation and deactivation of the transfer interrupt signal, respectively 2. A transfer address resetting means for resetting a transfer start address of a frame in which the transfer is interrupted to the data transfer unit in response to deactivation of the transfer interrupt signal. The CDROM decoding device according to the above. 3. The CDROM decoding apparatus according to claim 2, wherein said data input control means stops and restarts the input of said serial data by issuing each of a pause command and a pause release command of said CDROM drive. . 4. A CDROM decode data which outputs data read from a CDROM drive as serial data, decodes the serial data to generate decode data, and transfers the decode data to a host device as transfer data in frame units. In the transfer method, an overflow of a data buffer for temporarily storing the transfer data is performed.
Activating a transfer interruption signal indicating the transfer interruption in response to the occurrence of the transfer interruption factor including a flow; and activating the transfer of the serial data to the CDROM drive in response to the activation of the transfer interruption signal . Stopping output, waiting for resumption of retransfer of the transfer data due to disappearance of the cause of the transfer interruption, and deactivating the transfer interruption signal in response to disappearance of the cause of the transfer interruption. Waiting for transfer of the transfer data for one frame; and restarting the serial data output to the CD ROM drive.
ROM decode data transfer method.