JPH01217785A - Demodulation integrated circuit for compact disk - Google Patents

Abstract

PURPOSE:To automatically reproduce the music of a music program reproduced at the tie of turning off a power by receiving a start signal generated by detecting the energization of a power source by an external system controller and reading the music program data of the music reproduced immediately before the power source is disconnected from a non-volatile memory. CONSTITUTION:The music program of the music reproduced when the power source is turned off is stored in the non-volatile memory 7 by a music program data writing part 6, then, when the power source is energized, the contents of the memory 7 are read by a data reading part 8 automatically when the power source is energized and a system controller recognizes the contents of the music program indicating the read contents and controls an optical pickup driving part so as to move an optical pickup to the start part of the music program to start the reproduction of the music. Thereby, the music of the music program reproduced immediately before the disconnection of the power source can be reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a demodulation integrated circuit for compact discs, and more particularly to a demodulation integrated circuit for compact discs that stores the number of the music being played when the power is turned off.

[Conventional technology]

Conventionally, compact disc demodulation integrated circuits (hereinafter referred to as CD
When the power is turned on, the demodulation integrated circuit (referred to as a demodulation integrated circuit for
The track is being played from the beginning.

FIG. 2 is a diagram of a CD demodulation integrated circuit for explaining an example of such a conventional system.

As shown in FIG. 2, in such a CD demodulation integrated circuit, data read from a disc using an optical pickup is converted into a music signal by a demodulation section 1. Errors included in the music signal are corrected by the error correction processing unit 3 and the memory management unit 2 necessary for error correction, but if it is determined that error correction is impossible, output is processed according to the error situation. The processing unit 4 outputs it as music information. - On the other hand, the subcode processing unit 5 receives a subcode signal for the purpose of time display etc. from the demodulation unit 1, and performs error detection using a cyclic code and Q code processing.The output of the subcode processing unit 5 is externally processed. Sent as a control signal to the display driver. When the power is turned on, the system controller is reset and sorted, and the optical pickup returns to the starting position of song number 1 on the CD and starts playing the music from song number 1 on the CD.

[Problems to be Solved by the Invention] The conventional CD demodulation integrated circuit described above is
Among the multiple music programs recorded on the CD, music is played starting from the first song, so if you turn the power on and off frequently, you will end up playing the music with the lowest song number on the CD repeatedly. . Therefore, in order to play back the song that was being played when the power was turned off, the system controller first drives the optical pickup by selecting the desired song number using the 5KIP operation or numeric keypad operation, which saves the user time and effort. The disadvantage is that it takes a lot of time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a CD demodulation integrated circuit that can automatically reproduce the music of the track number that was being reproduced when the power was turned off.

[Means to solve the problem]

The demodulating integrated circuit for a CD of the present invention is a demodulator for a compact disc reproducing device that reproduces information by irradiating a light beam onto a compact disc provided with a thin film of recording material having a row of information bits recorded along the rotation direction. in the integrated circuit for controlling a demodulation unit that converts the recorded information into a music signal, an error correction processing unit that corrects data errors included in the demodulated music signal, and memory necessary for error correction processing. a memory management unit, and an interpolation process according to the error situation when the error correction unit determines that the error cannot be corrected;
An output processing section that performs preprocessing and muting processing, and a subcode signal included in the music signal converted by the demodulation section for the purpose of display, etc. are detected, and error detection using a cyclic code and a Q code are performed. A subcode processing unit that performs output,
a nonvolatile memory for storing track number data of music currently being played; a data writing unit connected to the subcode processing unit for storing track number data in the nonvolatile memory; and an external system. The controller includes a data reading section for reading out the song number data of the music that was being played immediately before the power was turned off from the nonvolatile memory in response to a startup signal generated when the controller detects power-on.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram of a CD demodulation integrated circuit for explaining one embodiment of the present invention.

As shown in FIG. 1, in such a CD demodulation integrated circuit, data read out from a CD by optical pickup is converted into a music signal by a demodulation section 1. Errors included in the music signal are corrected by the memory necessary for error correction controlled by the memory management unit 2 and the error correction unit 3. However, if it is determined that error correction is not possible, the errors are corrected according to the error situation. The output processing unit 4 performs interpolation processing, pre-processing, and muting processing, and outputs it to the outside as music information. - On the other hand, the subcode signal contained in the music signal converted by the demodulation unit 1 is processed by the subcode processing unit 5 for the purpose of display, etc.
performs error detection using a cyclic code and outputs a Q code, which is output to an external display control section. The song number data processed by the subcode processing section 5 is overwritten by the data writing section 6 in the nonvolatile memory 7 every time the song number data changes, and this data is retained even after the power is turned off.

On the other hand, when the power is turned on again, the data reading section 8 receives the activation signal from the system controller, reads out the song number data that was being played immediately before the power was turned off from the stored nonvolatile memory 7, and then the system controller Output to. As a result, the system controller drives the optical pickup to play from that track number. Incidentally, in the system controller, the built-in control section moves the optical pickup to the music information start part of the music number.

Furthermore, since the nonvolatile memory described in this embodiment requires a special integrated circuit manufacturing method and increases manufacturing costs, it may not be a good idea to place it on the same integrated circuit as the parts involved in compact disc demodulation. There is also. In that case, a non-volatile memory may be attached externally and only its control signal may be sent to this integrated circuit for processing, or a static RAM may be used instead of the non-volatile memory.
It is also possible to back up with a capacitor while the power is off.

As mentioned above, this embodiment stores the number of the track being played, so when the power is turned off and then turned on again, the system controller receives the activation signal and the system controller receives the information immediately before the power is turned off. By outputting the song number of the music that was being played back, the music of that song number can be played again, so that the music on the CD can be played on average regardless of the song number.

〔Effect of the invention〕

As explained above, the present invention records the number of the music being played when the power is turned off in memory, and when the power is turned on next time, the contents of the memory are automatically read out, and the system controller reads out the contents of the memory. When turning the power on and off frequently by recognizing the song number that indicates the content and controlling the optical pickup drive unit to move the optical pickup to the start part of that song number before starting music playback. This has the effect that it is possible to prevent only the music with the smallest song number on the CD from being played back, thereby improving the operability of the CD player.

[Brief explanation of the drawing]

FIG. 1 is a CD demodulation integrated circuit diagram for explaining one embodiment of the present invention, and FIG. 2 is a CD demodulation integrated circuit diagram for explaining an example of the conventional technology.
FIG. 2 is a demodulation integrated circuit diagram. DESCRIPTION OF SYMBOLS 1... Demodulation section, 2... Memory management section, 3... Error correction section, 4... Output processing section, 5... Subcode processing section, 6... Song number data writing section , 7... Nonvolatile memory, 8... Song number data reading unit.

Claims (1)

[Claims] A demodulating integrated circuit for a compact disc reproducing device that reproduces information by irradiating a light beam onto a compact disc provided with a thin film of recording material having a row of information bits recorded along the rotational direction. a demodulation section that converts information into a music signal; an error correction processing section that corrects data errors included in the demodulated music signal; a memory management section that controls memory necessary for error correction processing; and the error correction section. an output processing section that performs interpolation processing, pre-processing, and muting processing according to the error situation when it is determined that the error cannot be corrected; a subcode processing unit that detects the subcode signal, performs error detection using a cyclic code, and outputs a Q code; a nonvolatile memory for storing track number data of the music currently being played; A data writing section connected to the processing section for storing track number data in the non-volatile memory, and an external system controller detecting power-on and receiving a start signal generated, and were playing the song immediately before power-off. 1. A demodulation integrated circuit for a compact disc, comprising a data reading section for reading music track number data from the nonvolatile memory.