JPH0414679A - Data reproducing processor - Google Patents

Abstract

PURPOSE:To surely start read of a data from an object address (AD) by designating an AD smaller than a current AD by a prescribed AD again when the current AD is larger than an object AD at the start of read after search. CONSTITUTION:A processor uses a head AD of a map data corresponding to an inputted map number as an object AD, designates it as a header AD and gives it to a player controller 13 together with a read command. The controller 13 searches the object AD based on a sub code AD obtained from read information while moving a pickup 6 in the direction of the object AD. When the current AD obtained from a decoder 16 is coincident with the object AD, the processor gives a read start command of a disk to the controller 13. When the current AD is larger than the object AD, an AD smaller than the current AD by a prescribed AD is designated as a new object AD again, a designation flag is set and the search processing of the object AD is executed again.

Description

TECHNICAL FIELD The present invention relates to a data reproducing processing device, and more particularly to a data reproducing processing device that performs processing for reproducing data read from a memory disk conforming to the CD format.

BACKGROUND ART There is a CD-ROM as a storage medium of a read-only memory (ROM) for digital information, which utilizes a CD (compact disc), which has been established as a digital audio disc (hereinafter simply referred to as an audio disc). FIG. 3(A) shows the frame structure of the CD subcode, FIG. 3(B) shows the format of the subcode Q signal, and FIG. 4(A) shows the frame structure of the CD-ROM data. (B) l::cD-ROM data format and header format are shown, respectively.

As is clear from these figures, CD-ROM (hereinafter referred to as
(referred to as a memory disk) has the same signal format as a CD, so a CD-ROM cannot be used in a conventional disk player.
Data read from a memory disk can be reproduced by simply adding a decoder. That is, a disc player that reads data stored on a memory disc, and a CD-RO that decodes data read from this disc player.
A data reproduction processing device is constituted by the M decoder.

In this data reproducing processing device, read commands from the system controller, which controls the entire device,
The disc player reads the recorded data at the target address according to the process described below. In other words, when the system controller uses header address information (hereinafter referred to as header address) to specify a target address to start reading data and sends a read command,
In response to the read command, the controller on the disc player side (hereinafter referred to as the player controller) reads the specified target address from the address information in the subcode obtained from the read information from the memory disk (hereinafter referred to as the subcode address). ), and then begins the performance operation.

In this way, when specifying the target address by the header address and actually searching for the target address based on the subcode address, the header address and the subcode address do not necessarily match, so the subcode If the address is later than the header address in the time axis direction, the system controller may start reading data past the requested target address.
There is a possibility that it will be stored away. For example, when a memory disk is used as a storage medium for map data, map data has no meaning unless it is read from the beginning of one map unit, so if data reading is started past the target address, , this will cause a problem that the specified map cannot be displayed.

SUMMARY OF THE INVENTION C OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to provide a data reproduction processing device that can reliably start reading data from a memory disk from a designated target address.

[Structure of the Invention] The data reproduction processing device according to the present invention includes a reading means for reading recorded information on a memory disk conforming to the CD format, and a decoder for decoding data in the information read from the memory disk by the reading means. A data reproduction processing device comprising: means for specifying a target address indicating a search destination position of the reading means by a header address indicating a recording position of data recorded in blocks on a memory disk; and a means for specifying a target address indicating a search destination position of the reading means; means for controlling the reading means to move to the search destination position based on a subcode address obtained from the reading information in response; and means for controlling the reading means to move to the search destination position based on the subcode address obtained from the reading information; and means for re-designating an address smaller than the current address by a predetermined address as the target address when the obtained current address is larger than the target address.

[Operation of the Invention] In the data reproduction processing device according to the present invention, when a target address indicating a search destination position is specified by a header address and a search is performed based on a subcode address obtained from information read from a memory disk, When the current address obtained from the decoder output is larger than the target address at the start of reading after the search, an address smaller than the current address by a predetermined address is re-designated as a new target address.

EXAMPLE Hereinafter, an example of the present invention will be explained in detail based on the drawings.

In FIG. 1, the disc player is a so-called slot-in-cube audio disc/memory disc into which a disc (hereinafter referred to as audio disc and memory disc) 2 is inserted through a slot (not shown) formed on the front surface of the housing. It is a dual-purpose player. In this disc player, a disc 2 inserted through the slot is roped by a loading mechanism 3, loaded into a table 4 serving as a playing position, and rotated by a spindle motor 5.

Recorded information on the disc 2 is read by an optical pickup 6. The pickup 6 is mounted on a slider (not shown) that moves in the radial direction of the disk 1 using a slider motor 7 as a driving source.

In the case of a CD format signal, the output signal of the pickup 6 is E F M (Eight to Fourth
n Modulatlon) signal, and this read EF
The M signal passes through the RF amplifier 8 and is EF'd by the EFM demodulation circuit 9.
After the M demodulation, it is supplied to the subcode decoder 10, error corrected by the error correction circuit 11, and D/
The A converter 12 converts the signal into an analog signal and outputs it as a reproduced audio signal. The subcode decoder 10 decodes subcode information inserted in each frame, such as the song number, index, time and frame number within the song, and absolute time and frame number within the disc. is performed, and the decoded data is supplied to the player controller 13. In this embodiment, it is assumed that map data, for example, is stored in the memory disk.

The player controller 13 is constituted by a microcomputer, and the drive control of the loading mechanism 3 and the slider drive circuit 14 are controlled by the processor.
The position of the pickup 6 in the disk radial direction is controlled by driving the slider 7-tough via the spindle drive circuit 15, and the drive of the spindle motor 5 is controlled via the spindle drive circuit 15.

The demodulated output of the EFM demodulation circuit 9 is also supplied to the CD-ROM decoder 16. CD-ROM
The decoder 16 decodes map data obtained by reading from a memory disk (CD-ROM) and demodulating it with the EFM demodulation circuit 9, and supplies the decoded map data to the image display controller 20 via a path line BL made of, for example, an optical fiber. The image display controller 20 performs control to display images such as maps on a display unit 19 such as a liquid crystal display based on display information signals such as map data supplied from the CD-ROM decoder 16.

The system controller 17 is constituted by a microcomputer and controls the entire system. A player controller 13 and a CD-ROM decoder 16 are connected to the system controller 17 via a path line BL, respectively, so that information is exchanged with the controller 17. The pass line BL is further connected to an operation unit 18 that issues various commands such as designation of a map number and designation of an audio disc/memory disc by manual keystrokes by the user.

Next, the processing procedure executed by the processor of the system controller 17 when reading the map data of a desired map from the memory disk will be explained with reference to the flowchart of FIG.

It is assumed that this routine is called and executed, for example, when the user issues a reading command by manually inputting a desired map number on the operation unit 18.

First, the processor specifies the header address of the map data corresponding to the map number keyed by the user as the target address and sends it to the player controller 13 along with a read command (step S1), and then the CD-decoder 16 reads the map data from the memory. Waiting for the start of decoding of data read from the disk (step S2). At this time, the player controller 13 searches for the target address based on the subcode address obtained from the read information while moving the pickup 6 in the direction of the target address in response to the read command. control to start reading.

When the CD-decoder 16 starts decoding the read data, the processor determines whether the current address (header address) obtained from the decoded output matches the target address (step S3), and if it is determined that they match - In step S4), a command to start reading the disc is issued to the player controller 13, and then, based on the header address obtained from the decoder output, it is monitored until the reading of the necessary data is completed (step S5).
After reading the necessary data, a pause command is sent to the player controller 13 (step S6). This pause command causes the disc player 1 to enter a pause state.

If it is determined in step S3 that the current address and the target address do not match, the processor determines whether the current address is larger than the target address (step S7), and if it is smaller, both addresses Repeat the process of returning to step S3 until they match, and if they are large,
It is determined whether a re-designation flag, which will be described later, is set (step S8). If the re-designation flag is not set, the processor calculates the difference between both addresses (current address - target address) (step S9), and re-designates the address that is smaller than the first target address by the difference between the two addresses as a new target address. In step 510), a re-designation flag indicating that the target address has been re-designated is set (step 511), and then the process returns to step S1 to execute the target address search process again.

If it is determined in step S8 that the re-designation flag is set, this means that the two addresses did not match in the second search process (the target address could not be searched), so the processor , to reset the re-designation flag (step 512), and the image display controller 2 to display a message on the display unit 19 stating, for example, "operation stopped due to inability to search for target address".
0 (step 813), then step S6
to move to.

In the above embodiment, the series of processes described above are executed by the processor of the system controller 17, but for example, the processor of the image display controller 20 may be in charge of executing the processes described above.

As described in detail, the data reproduction processing device according to the present invention specifies a target address indicating a search destination position using a header address, and performs a search based on a subcode address obtained from information read from a memory disk. When the current address obtained from the decoder output becomes larger than the target address at the start of reading after the search, the configuration is such that when the current address obtained from the decoder output is larger than the target address, an address smaller than the current address by a predetermined address is re-specified as the new target address. , it is possible to reliably start reading data from the memory disk from the specified target address.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a flowchart showing the processing procedure when reading data executed by the processor of the system controller, and Fig. 3 (A) is a subcode of the CD. 4(B) shows the format of the subcode Q signal, FIG. 4(A) shows the frame structure of CD-ROM data, and FIG. 4(B) shows the CD-ROM data format and header. It is a figure which shows each format. Explanation of symbols of main parts 1...Disc player 3...Loading mechanism 6...Pickup 9...EFM demodulation circuit 10...Sub Code decoder 13...Player controller 16...
・CD-ROM decoder 17... System controller, controller

Claims (2)

[Claims] (1) A data reproduction processing device including a reading means for reading recorded information of a memory disk conforming to the CD format, and a decoder for decoding data in the information read from the memory disk by the reading means, the memory means for specifying a target address indicating a search destination position of the reading means based on address information of a header indicating a recording position of data recorded in blocks on a disk; and means for specifying a target address indicating a search destination position of the reading means; means for controlling the reading means to move to the search destination position based on address information in the subcode that is searched; and a current address obtained from the output of the decoder when the reading means starts reading from the search destination position. A data reproduction processing device comprising: means for re-designating an address smaller than the current address by a predetermined address as the target address when the current address is larger than the target address. (2) The data reproduction processing device according to claim 1, wherein the predetermined address is an address difference between the current address and the target address at the time of starting the reading.