JP2005025938A - Controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To assure the continuity of record data to be recorded on a recording medium. <P>SOLUTION: In recording operation, the input data read out of a buffer memory 13 is modulated by an encoder and the record data is formed. The record data is recorded to an optical disk 32. In the state that a buffer underrun occurs in the buffer memory 13 during the recording operation, the record data modulated at the point of time is recorded to the optical disk and the recording operation is interrupted from the next record data. When the state that the buffer underrun occurs is avoided thereafter, the recording operation is returned by as much as the prescribed number of sectors of the optical disk 32 and the reproduction operation is started and the recording operation is restarted from the record data next to the record data interrupted in the recording operation. An interruption/restart circuit 43 interrupts the operation of the encoder 14 at the timing of the low level of the record data outputted by the encoder 14. The laser power of an optical head 4 is consequently weakened at the time of restarting the recording operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a data recording apparatus, and more particularly to a data recording apparatus that includes a buffer memory that stores input data input from an external device and records the input data stored in the buffer memory on a recording medium. .

2. Description of the Related Art Conventionally, an optical disk recording apparatus using an optical disk as a recording medium is known as a data recording apparatus that records data on a recording medium.
As such an optical disk recording apparatus, data can be recorded (written) on an optical disk only once, and the recorded (written) data cannot be physically erased, so-called. A CD-R (CD-Recordable) drive of the CD (CompactDisc) -DA family is widely used as a write-once type optical disk. In a CD-R drive, a recording pit is formed in a recording layer of an optical disk by irradiating the optical disk with a laser beam from an optical head, using dye formation by laser light heat, and the reflectance of the recording layer is changed. Record the recorded data.

  An optical disk recording device stores a buffer memory for storing input data input from an external device such as a personal computer, reads the input data stored in the buffer memory, and modulates the input data into recording data for recording on the optical disk Encoder.

  Therefore, the data transfer rate of the input data input from the external device cannot keep up with the data transfer rate (write speed) of the recording data recorded on the optical disc, and compared with the data transfer rate of the recording data output from the encoder. Thus, when the data transfer rate of the input data input to the encoder becomes low, the data capacity of the input data stored in the buffer memory decreases. If this state continues, the data capacity of the input data stored in the buffer memory will eventually become empty (empty). Then, the desired input data is not input to the encoder, and the recording data recorded on the optical disc is interrupted.

  The phenomenon in which the data transfer rate of the input data input from the external device becomes slower than the data transfer rate of the recording data recorded on the optical disc and the data capacity of the buffer memory becomes empty is called buffer underrun. . A phenomenon in which recording data recorded on the optical disc is interrupted as a result of the occurrence of a buffer underrun is called a buffer underrun error.

  In a write-once optical disc used in a CD-R drive, when a buffer underrun error occurs, a recording method for specifying a file group to be recorded on the optical disc (for example, disc at once, track at once ( When using Track At Once), etc., the entire optical disc cannot be used with Disc At Once, and the track being recorded cannot be used with Track At Once.

  In recent years, the recording speed in a CD-R drive has been further increased to 4 times or 8 times the standard speed, and the opportunity to operate using a multitask function in a personal computer has increased. Run errors are more likely to occur.

  By the way, if packet writing is used as a recording method, recording can be performed in units of packets. Therefore, it is possible to prevent occurrence of a buffer underrun error by recording until the recording data reaches the capacity in units of packets. . However, packet writing has a problem that the recording capacity of the optical disk is reduced because it is necessary to form a link block for connection between packets. In addition, CD-ROM drives do not always support packet writing, and some CD-ROM drives cannot reproduce optical disks recorded with CD-R drives using packet writing. Compatibility with CD-ROM that must be guaranteed under Orange Book Part II) may not be guaranteed. Since the CD-DA player does not support packet writing, packet writing cannot be employed when recording audio data corresponding to CD-DA with a CD-R drive. Therefore, it is required to prevent the occurrence of a buffer underrun error without using packet writing as a recording method.

  Incidentally, CD-RW (CD-Recordable Write) drives are also widely used as optical disk recording devices. In the CD-RW drive, a recording pit is formed in the recording layer of the optical disk by irradiating the optical disk with a laser beam from the optical head, using a crystalline / amorphous phase change caused by laser light heat, and the reflectance of the recording layer Change the to record recording data. Therefore, the optical disc used in the CD-RW drive can re-record (rewrite) data any number of times, and even if a buffer underrun error occurs, the optical disc cannot be used. However, if a buffer underrun error occurs, you must go back to the beginning of the recorded data file before the buffer underrun occurs, and the data recorded before the occurrence of the buffer underrun is wasted. The time required for the recording operation increases.

  Further, as a data recording apparatus for recording data on a recording medium, a magneto-optical disk is used as the recording medium, and the magneto-optical disk is irradiated with a laser beam from an optical head, whereby residual magnetization is applied to the recording layer of the magneto-optical disk. There is known a magneto-optical disk recording apparatus which records data by giving As such a magneto-optical disk recording apparatus, an MD (Mini Disc) drive is widely used. However, the MD drive has the same problem as the CD-RW drive.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a data recording apparatus capable of recording while ensuring continuity of recording data recorded on a recording medium. It is in.

The present invention has been made in order to solve the above-described problems. When data stored in a buffer memory is written to a recording medium by repeating high-level or low-level laser irradiation, data writing is suspended / resumed. A control device for controlling at least one of an address indicating a position on the recording medium corresponding to an interruption position and an address indicating a position on the buffer memory corresponding to the interruption position when the data writing to the recording medium is interrupted; An address memory for storing one of them, and a restart circuit for instructing restart of data writing to the recording medium based on an address stored in the address memory while reading data written to the recording medium, The buffer underrun occurs due to the data capacity stored in the buffer memory becoming empty. If it is determined that the laser irradiation gives a data write interruption instruction during a period when the laser irradiation is at a low level, and it is determined that a state in which a buffer underrun occurs is avoided after the interruption instruction, the restart circuit Is a control device that instructs resumption of data writing to the recording medium during a period when the laser irradiation is at a low level.
Further, the control device of the data recording apparatus stores the input data input from the external device in a buffer memory, and records the data by irradiating the recording medium with a laser according to the input data. During operation, when it is detected that a buffer underrun occurs due to the data capacity stored in the buffer memory becoming empty, recording is performed at the timing when the power level of the laser beam applied to the recording medium decreases. When the operation is interrupted and then a state in which a buffer underrun occurs is avoided, the control device restarts the recording operation at a timing when the power level of the laser beam applied to the recording medium becomes small.

  According to the present invention, an instruction to interrupt data writing is given during a period when the laser irradiation is at a low level, or the recording operation is interrupted at the timing when the power level of the laser beam becomes small. Even if the recording data is overwritten when the recording operation is resumed, the recording pits can be prevented from being abnormally formed.

  In particular, since the recording operation is interrupted at the timing when the power level of the laser beam is reduced in the sector synchronization pattern, the low level is 11 bits continuous in the sector synchronization pattern, which is optimal as a recording operation interruption position. In addition, since an address is assigned to the sector, if this address is stored in the address memories 47 and 48, the recording can be easily resumed.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.

  FIG. 1 is a block circuit diagram showing a schematic configuration of a CD-R drive 1 of the present embodiment.

  The CD-R drive 1 includes a spindle motor 2, a spindle servo circuit 3, an optical head 4, an RF amplifier 5, a head servo circuit 6, a decoder 7, a subcode demodulation circuit 8, a wobble decoder 9, an ATIP demodulation circuit 10, and an external connection terminal. 11, interface 12, buffer memory 13, encoder 14, encoder internal RAM 15, laser drive circuit 16, crystal oscillation circuit 18, access control circuit 19, buffer underrun determination circuit 20, recording control circuit 21, and system control circuit 22. ing. The CD-R drive 1 is connected to a personal computer 31 which is an external device via an external connection terminal 11 and records (writes) data input from the personal computer 31 on a CD-R standard optical disc 32. The data reproduced (read) from the optical disk 32 is output to the personal computer 31.

  The spindle motor 2 drives the optical disk 32 to rotate. The spindle servo circuit 3 controls the rotation of the spindle motor 2 based on the rotation control signal generated by the wobble decoder 9, thereby controlling the rotation of the constant linear velocity (CLV) type optical disk 32.

  The optical head 4 irradiates the optical disk 32 with a weak laser beam during a reproducing operation (reading operation) for reproducing recorded data from the optical disk 32, and the optical head 4 is already recorded on the optical disk 32 by the reflected light of the laser beam. The recorded data is reproduced (read), and an RF signal (high frequency signal) corresponding to the recorded data is output. Further, the optical head 4 irradiates the optical disk 32 with a strong laser beam (several tens of times during the reproduction operation) during the recording operation (writing operation) for recording the recording data on the optical disc 32, Recording pits are formed in the recording layer of the optical disk 32 by using dye formation by laser light heat, and recording data is recorded (written) by changing the reflectance of the recording layer. At the same time, the optical disk 32 is reflected by the reflected light of the laser beam. The recorded data recorded in (1) is reproduced to output an RF signal.

  The RF amplifier 5 amplifies the RF signal output from the optical head 4, binarizes the RF signal, and outputs it as digital data. The head servo circuit 6 feeds back the output of the optical head 4 via the RF amplifier 5 to focus the laser beam on the recording layer of the optical disc 32 and to cause the laser beam to follow the signal track of the optical disc 32. Tracking control and sled feed control for feeding the optical head 4 itself in the radial direction of the optical disk 32 are performed.

  The decoder 7 performs signal processing for demodulating the digital data output from the RF amplifier 5, extracts a pit clock from the digital data, separates a subcode, and extracts a subcode synchronization signal. The subcode demodulating circuit 8 is provided in the decoder 7, demodulates the subcode separated by the decoder 7, and extracts subchannel Q channel data (hereinafter referred to as “subQ data”).

  The wobble decoder 9 extracts a 22.05 kHz wobble component from the pre-groove signal of the optical disk 32 included in the digital data output from the RF amplifier 5, and is necessary for controlling the rotation of the optical disk 32. A rotation control signal is generated.

  The ATIP demodulation circuit 10 is provided in the wobble decoder 9, demodulates ATIP (Absolute Time In Pre-groove) from the wobble component extracted by the wobble decoder 9, and extracts an ATIP address of absolute time information in ATIP. The interface 12 controls data exchange between the personal computer 31 connected to the external connection terminal 11 and the CD-R drive 1.

  The buffer memory 13 is constituted by a ring buffer composed of a SDRAM (Synchronous Dynamic Random Access Memory) having a FIFO structure, and stores input data input from the personal computer 31 via the interface 12. The input data stored at one address in the buffer memory 13 corresponds to the recording data recorded in one sector on the optical disc 32. The encoder 14 is controlled by the interruption / resumption circuit 43 of the system control circuit 22, reads the input data stored in the buffer memory 13 in units of sectors on the optical disc 32, and records the input data in units of sectors on the optical disc 32. The data is modulated into recording data in units of sectors. The RAM 15 is provided in the encoder 14 and stores data necessary for the modulation processing by the encoder 14 and intermediate calculation data in the modulation processing.

  When performing modulation based on the CD-ROM standard, the encoder 14 performs sync, header, error detection code EDC (Error Detection Code) for CD-ROM data, and error correction code ECC on input data. (Error Correction Code) is added, and then a CIRC (Cross Interleaved Reed-Solomon Code) process and an EFM (Eight to Fourteen Modulation) process are performed, and sub-Q data is included. A subcode and a subcode synchronization signal are added.

  The laser drive circuit 16 is controlled by the interruption / resumption circuit 43 and outputs a drive signal for driving the laser light source of the optical head 4.

  Here, the drive signal output from the laser drive circuit 16 is set to a constant voltage during the reproducing operation, and is varied to a voltage based on the recording data output from the encoder 14 during the recording operation. That is, during the recording operation, when the recording data output from the encoder 14 is low (L) level (when recording pits are not formed in the recording layer of the optical disc 32), the voltage of the drive signal output from the laser drive circuit 16 is , It is set to the same level as during playback operation. When the recording data output from the encoder 14 is high (H) level (when recording pits are formed in the recording layer of the optical disc 32), the voltage of the drive signal output from the laser drive circuit 16 is the track of the optical disc 32. Although it differs depending on the position, it is set to a level several tens of times that in the playback operation.

  The crystal oscillation circuit 18 generates an oscillation signal from a crystal oscillator.

  The access control circuit 19 selectively refers to the subcode address of the absolute time information in the demodulated sub-Q data of the subcode demodulation circuit 8 and the ATIP address of the absolute time information in the ATIP demodulated by the ATIP demodulation circuit 10, Based on this, the access to the optical disk 32 is controlled by controlling the operations of the recording control circuit 21 and the head servo circuit 6.

  Input data is stored in the buffer memory 13 in the order of addresses. The buffer underrun determination circuit 20 directly or indirectly determines the data capacity of the input data stored in the buffer memory 13 based on the address currently being written or read in the buffer memory 13, and the data Based on the capacity, it is determined that a buffer underrun has occurred in the buffer memory 13 and that a buffer underrun has been avoided.

  The recording control circuit 21 performs operations of the interface 12, the access control circuit 19, and the system control circuit 22 based on the determination result of the buffer underrun determination circuit 20 in accordance with the command transferred from the personal computer 31 through the interface 12. By controlling it, the recording operation is controlled.

  The system control circuit 22 includes a system clock generation circuit 41, a signal synchronization circuit 42, an interruption / resumption circuit 43, a retry determination circuit 44, position detection circuits 45 and 46, and address memories 47 and 48. The circuits 41 to 48 constituting the system control circuit 22 are mounted on a one-chip LSI.

  The system clock generation circuit 41 generates a reference clock to be used at the time of recording operation based on the oscillation signal generated by the crystal oscillation circuit 18 and reproduces to be used at the time of reproduction operation of the optical disc 32 based on the pit clock extracted by the decoder 7. Based on the switching control of the signal synchronization circuit 42, either one of the reference clock and the reproduction clock is switched and the selected clock is used as the operation clock (used for system control of the CD-R drive 1). System clock). In accordance with the operation clock, the synchronous operation of the circuits 7 to 10, 12 to 16, and 19 to 22 of the CD-R drive 1 is controlled.

  The signal synchronization circuit 42 synchronizes the synchronization signal of the subcode added by the encoder 14 with the synchronization signal of the subcode extracted by the decoder 7, and then the sub-Q data demodulated by the subcode demodulation circuit 8. The operation of the recording control circuit 21 is made to synchronize the recording data output from the encoder 14 with the recording data already recorded on the optical disc 32 by making the sub Q data added by the encoder 14 correspond. To control. Further, the signal synchronization circuit 42 controls the system clock generation circuit 41 to output one of the reference clock and the reproduction clock as an operation clock.

  The interruption / resumption circuit 43 is controlled by the recording control circuit 21 and controls the operation of the encoder 14 and the laser drive circuit 16 based on the level of the recording data output from the encoder 14 and is also controlled by the buffer underrun determination circuit 20. When it is determined that a buffer underrun has occurred in the buffer memory 13, an interruption signal is output to each of the address memories 47 and 48.

  The address memory 47 stores and holds the address in the buffer memory 13 of the input data read from the buffer memory 13 when the interruption signal is output from the interruption / resumption circuit 43. The address memory 48 stores and holds the ATIP address demodulated by the ATIP demodulation circuit 10 at the time when the interruption signal is output from the interruption / resumption circuit 43.

  The position detection circuit 45 compares the address in the buffer memory 13 of the input data read from the buffer memory 13 and the address stored in the address memory 47 in the reproducing operation at the time of resuming recording to be described later. When detected, a restart signal is output. The position detection circuit 46 compares the ATIP address demodulated by the ATIP demodulator circuit 10 with the ATIP address stored in the address memory 48 in a reproducing operation when resuming recording, which will be described later, and detects the coincidence state of both. A restart signal is output.

  The retry determination circuit 44 uses the restart signals from the position detection circuits 45 and 46 as triggers, and when both restart signals are output at the same time, the interface 12, the access control circuit 19, and the system control circuit 22 via the recording control circuit 21. If the resumption signal is not output simultaneously (when the output timing of each resumption signal is deviated), the resumption operation at the time of resuming recording will be described until each resumption signal is outputted simultaneously. Is repeatedly executed.

  Next, the operation of the CD-R drive 1 of the present embodiment configured as described above will be described.

  When the user performs an operation for executing a recording operation using the personal computer 31, a command corresponding to the operation is generated from the personal computer 31, and the command is transferred to the recording control circuit 21 via the interface 12. . Then, the recording control circuit 21 controls the operations of the interface 12, the access control circuit 19, and the system control circuit 22 according to a command from the personal computer 31 to execute the recording operation.

  When the recording operation is started, the operation clock output from the system clock generation circuit 41 is controlled to be switched to the reference clock by the signal synchronization circuit 42. As a result, the circuits 7 to 10, 12 to 16, and 19 to 22 of the CD-R drive 1 use the reference clock as an operation clock and operate in synchronization with the operation clock.

  Input data input from the personal computer 31 via the interface 12 is stored in the buffer memory 13, read out from the buffer memory 13 in units of sectors in the optical disk 32, transferred to the encoder 14, and sectored by the encoder 14. Modulated into recording data in units.

  Based on the recording data modulated by the encoder 14, the voltage of the drive signal output from the laser drive circuit 16 is varied, and the intensity of the laser beam emitted from the optical head 4 to the optical disk 32 is also varied. Recording pits are formed in the recording layer, and recording data is recorded. At the same time, the recorded data recorded on the optical disk 32 is reproduced by the reflected light of the laser beam irradiated to the optical disk 32 from the optical head 4, and the recorded data is output from the optical head 4 as an RF signal.

  The RF signal output from the optical head 4 is amplified and binarized by the RF amplifier 5 and converted into digital data. A wobble component is extracted from the digital data by the wobble decoder 9, and a rotation control signal is generated. Then, the ATIP demodulation circuit 10 demodulates the ATIP from the wobble component extracted by the wobble decoder 9, and the ATIP address of the absolute time information in ATIP is extracted.

  Based on the rotation control signal generated by the wobble decoder 9, the spindle servo circuit 3 controls the rotation of the spindle motor 2, and the rotation of the optical disc 32 is controlled at a constant linear velocity. At this time, the data transfer rate of the input data input from the personal computer 31 cannot keep up with the data transfer rate (write speed) of the recording data recorded on the optical disc 32, and the data of the recording data output from the encoder 14 is reached. When the data transfer rate of the input data input to the encoder 14 becomes lower than the transfer rate, the data capacity of the input data stored in the buffer memory 13 decreases.

  If this state continues, the data capacity of the input data stored in the buffer memory 13 will eventually become empty (empty), and a buffer underrun will occur. Therefore, before the buffer underrun occurs in the buffer memory 13, the buffer underrun determination circuit 20 determines that the buffer underrun has occurred. Based on the determination result, the recording control circuit 21 controls the interruption / resumption circuit 43 to output an interruption signal from the interruption / resumption circuit 43 and also interrupts the output of recording data from the encoder 14 by the interruption / resumption circuit 43. Let

  At this time, based on the level of the recording data output from the encoder 14, the interruption / resumption circuit 43 outputs an interruption signal and interrupts the output of the recording data from the encoder 14 at a timing when the recording data is at a low level. Using the interruption signal as a trigger, each of the address memories 47 and 48 stores and holds the address input at that time. That is, the address memory 47 stores and holds the address in the buffer memory 13 of the input data read from the buffer memory 13 when the interruption signal is output. The address memory 48 stores and holds the ATIP address demodulated by the ATIP demodulation circuit 10 at the time when the interruption signal is output.

  Then, the output of the recording data from the encoder 14 is interrupted, the output of the driving signal from the laser driving circuit 16 is interrupted, the irradiation of the laser beam from the optical head 4 is stopped, and the recording data to the optical disk 32 is stopped. Recording is interrupted, and the recording operation is interrupted. Note that when the interruption signal is output from the interruption / resumption circuit 43, the sector of the recording data output from the encoder 14 is recorded on the optical disc 32. At this time, the interruption signal from the interruption / resumption circuit 43 is preferably output between the sectors of the recording data.

  Thereafter, when new input data is input from the personal computer 31 via the interface 12, and the input data is stored in the buffer memory 13, the data capacity of the input data stored in the buffer memory 13 increases, and the buffer underflow A situation where a run occurs is avoided. Therefore, the buffer underrun determination circuit 20 determines that the state in which the buffer underrun has occurred has been avoided. Based on the determination result, the recording control circuit 21 controls the operations of the access control circuit 19 and the system control circuit 22 to execute the reproducing operation at the time of resuming recording.

  When the reproduction operation at the time of resuming recording is started, the head servo circuit 6 is controlled by the access control circuit 19. The head servo circuit 6 controls the optical head 4 (focusing control, tracking control, and thread feed control), so that the buffer underrun occurs and the recording operation is interrupted from the sector position of the optical disk 32. A laser beam is irradiated from the optical head 4 to a sector position returned by a predetermined number of sectors.

  Then, under the control of the interrupt / restart circuit 43, the voltage of the drive signal output from the laser drive circuit 16 is set to a constant voltage, and a weak laser beam is irradiated from the optical head 4 to the optical disk 32, and the reflected light of the laser beam Recording data already recorded on the optical disc 32 is reproduced by the recording operation, and the recording data is output from the optical head 4 as an RF signal.

  The RF signal output from the optical head 4 is amplified by the RF amplifier 5 and binarized to be converted into digital data. The digital data is demodulated by the decoder 7, a pit clock is extracted from the digital data, a subcode is separated, and a subcode synchronization signal is extracted. Then, the subcode separated by the decoder 7 is demodulated by the subcode demodulating circuit 8, and subQ data is extracted.

  When the reproduction operation is resumed when recording is resumed, the operation clock output from the system clock generation circuit 41 is derived from the reference clock generated based on the oscillation signal of the crystal oscillation circuit 18 by the signal synchronization circuit 42 from the decoder 7. Is switched to a reproduction clock generated based on the extracted pit clock. As a result, each of the circuits 7 to 10, 12 to 16, and 19 to 22 of the CD-R drive 1 is in a state of operating in synchronization with the operation clock using the reproduction clock as the operation clock. Thus, by using the reproduction clock as the operation clock, it is possible to accurately reproduce the recording data already recorded on the optical disc 32 by the recording operation.

  By the way, when the reproduction operation at the time of resuming recording is started, the recording control circuit 21 controls the interruption / resumption circuit 43, and the interruption / resumption circuit 43 resumes the output of the recording data from the encoder 14. The encoder 14 returns from the address of the recording data in the buffer memory 13 at the time when the recording operation is interrupted due to the occurrence of a buffer underrun, by the predetermined number of addresses corresponding to the predetermined number of sectors. Sequentially, the input data stored in the buffer memory 13 is read again in units of sectors. Then, the encoder 14 modulates the sector-unit input data read from the buffer memory 13 into recording data, adds a sync, header, EDC, and ECC to the input data, and then performs CIRC processing and EFM processing. And a subcode including subQ data and a subcode synchronization signal are added.

  Here, as described above, the voltage of the drive signal of the laser drive circuit 16 is controlled by the interruption / resumption circuit 43 and is set to a constant voltage during the reproduction operation regardless of the recording data modulated by the encoder 14. The That is, in the recording resumption reproduction operation executed after the recording operation is interrupted due to the occurrence of a buffer underrun, the buffer memory 13 and the encoder 14 perform the same operation as the recording operation, but the laser drive circuit 16 Since the voltage of the drive signal is set at a low level during the reproducing operation, it does not affect the recording data already recorded on the optical disc 32 by the recording operation before the buffer underrun occurs. Absent.

  Then, the access control circuit 19 is controlled by the signal synchronization circuit 42 via the recording control circuit 21, and the recording data output from the encoder 14 is synchronized with the recording data already recorded on the optical disc 32. That is, the signal synchronization circuit 42 synchronizes the synchronization signal of the subcode added by the encoder 14 with the synchronization signal of the subcode extracted by the decoder 7, and then the demodulated sub-Q data of the subcode demodulation circuit 8. On the other hand, the operations of the recording control circuit 21 and the access control circuit 19 are controlled so as to correspond to the sub-Q data added by the encoder 14.

  The position detection circuit 45 records the address in the buffer memory 13 of the input data read from the buffer memory 13 in the reproduction operation when resuming recording, and the address stored in the address memory 47 (buffer underrun occurs in a state where recording occurs). When the operation is interrupted, the input data read from the buffer memory 13 is compared with the address in the buffer memory 13, and a restart signal is output when the coincidence state is detected.

  In addition, the position detection circuit 46 performs the recording operation when the ATIP address demodulated by the ATIP demodulation circuit 10 in the reproduction operation when resuming recording and the ATIP address stored in the address memory 48 (buffer underrun occurs). At the time of interruption, the ATIP demodulation circuit 10 demodulates the ATIP address), and when a coincidence state is detected, a restart signal is output.

  The retry determination circuit 44 uses the restart signals from the position detection circuits 45 and 46 as triggers, and when both restart signals are output at the same time, the interface 12, the access control circuit 19, and the system control circuit 22 via the recording control circuit 21. The recording operation is resumed by controlling the operation.

  When the recording operation is resumed, the operation clock output from the system clock generation circuit 41 is switched from the reproduction clock to the reference clock again by the signal synchronization circuit 42. Then, the same operation as the recording operation is performed. When the recording operation is resumed, the address of the input data read out from the buffer memory 13 by the operation of the address memory 47 and the position detection circuit 45 becomes the state where the buffer underrun occurs and the recording operation is interrupted. This is the next address after the address in the buffer memory 13.

  When the recording operation is resumed, the operation of the address memory 48 and the position detection circuit 46 causes the sector position of the optical disk 32 irradiated with the laser beam from the optical head 4 to be in a state where a buffer underrun occurs. It is the sector position next to the sector position at the time when the operation is interrupted.

  At this time, as described above, the signal synchronization circuit 42 synchronizes the recording data output from the encoder 14 with the recording data already recorded on the optical disc 32. Therefore, in the optical disc 32, the recording data of the next sector can be recorded from the position that continues seamlessly to the sector at the time when the recording operation is interrupted due to the occurrence of buffer underrun. Therefore, without using packet writing as a recording method, it is possible to prevent occurrence of a buffer underrun error in which data recorded on the optical disc 32 is interrupted, and to record while ensuring the continuity of the recorded data.

  By the way, as described above, when the recording operation is interrupted due to the occurrence of a buffer underrun, the interruption / resumption circuit 43 outputs the recording data output from the encoder 14 from the encoder 14 at a low level timing. The output of the recorded data is interrupted. Therefore, the recording data output from the encoder 14 is at a low level when the state where the buffer underrun occurs is avoided and the recording operation is resumed, and the drive signal output from the laser drive circuit 16 is the same as that during the reproduction operation. The power of the laser beam irradiated from the optical head 4 (laser power) is weak (small).

  That is, when the recording data output from the encoder 14 is at a high level when the recording operation is interrupted, the voltage of the driving signal output from the laser driving circuit 16 varies depending on the track position of the optical disc 32, but during the reproducing operation. The level is set to several tens of times. Therefore, when the recording operation is interrupted, the laser power of the optical head 4 is set to a level several tens of times that during the reproducing operation. However, the laser power of the optical head 4 cannot be raised instantaneously from the level at the time of reproducing operation to a level several tens of times that time, and a certain time is required for the rise. Therefore, when the laser power of the optical head 4 is raised when the recording operation is resumed, it takes time until the laser power reaches a desired level, and an unrecorded area is generated on the optical disc 32 by the time delay, and recording is performed. Data may be interrupted.

  Further, when the recording operation is resumed, the sector position of the optical disk 32 irradiated with the laser beam from the optical head 4 is shifted due to some cause, and when the recording operation is interrupted, the sector position where the recording data has already been recorded is returned again. There may be a malfunction such as recording data (overwriting the recording data). In this case, since the laser beam is again irradiated from the optical head 4 to the recording pits already formed in the recording layer of the optical disc 32, the laser power of the optical head 4 is strong (large) when the recording operation is resumed. Then, there is a problem that the diameter of the recording pit becomes excessively large and the recording pit is formed on another sector or track, and normal recording cannot be performed. In addition, if the recording resumption timing is delayed, an unrecorded area is generated at the recording resumption point, and pits that should be continued are divided, and incorrect data is recorded. Even if the recording restart position completely coincides with the interruption position, the power of the writing laser is slightly different before and after the interruption. Then, the diameter of the recording pit becomes discontinuous at the restart position, and there is a possibility that a data reading error occurs at this position.

  Therefore, the timing for interrupting the recording operation is set to a timing at which the recording data output from the encoder 14 is at a low level. When the recording data is at a low level, the power of the laser beam of the optical head 4 is weak. Therefore, when the recording operation is resumed from the same position, the recording data output from the encoder 14 is at a low level, and the power of the laser beam of the optical head 4 is also weak. Therefore, even if the recording restart position is shifted, already recorded data is not destroyed. Even if the restart timing is delayed, the pit diameter does not become discontinuous because the region is originally not irradiated with the laser.

  The most suitable point for interrupting data writing is the synchronization pattern at the head of each sector. In the CD standard data, there is a 24-bit synchronization pattern having a pattern of 11 bits each of high and low at the head of each sector. That is, there is a row period of 11 bits at the head of each sector. This low period is the longest continuous period in the CD standard data. Since each sector is given an address, the address memories 47 and 48 may hold address data corresponding to the sector address. From the above viewpoint, the sector synchronization pattern is optimal as the data interruption position.

  As a result, it is not necessary to raise the laser power of the optical head 4 when the recording operation is resumed, and the above-described abnormal formation of recording pits can be prevented even when the recording data is overwritten when the recording operation is resumed.

  In this case, the buffer underrun determination circuit 20 is set so as to determine that a buffer underrun has occurred while at least one sector of data remains in the buffer memory 13. Good.

  By the way, the retry determination circuit 44 resumes the recording until the restart signals are simultaneously output when the restart signals of the position detection circuits 45 and 46 are not output simultaneously (when the output timing of the restart signals is shifted). Repeat the playback operation.

  That is, the restart signals of the position detection circuits 45 and 46 should be output at the same time in a normal state, but for some reason (for example, when an external impact is applied to the CD-R drive 1). When the constituent members 2 to 22 of the CD-R drive 1 malfunction due to the disturbance generated in step 1, the respective restart signals may not be output at the same time. Therefore, the retry determination circuit 44 repeatedly executes the reproduction operation when resuming recording, thereby avoiding the influence of the disturbance and reliably preventing the occurrence of a buffer underrun error. However, it goes without saying that the retry determination circuit 44, the position detection circuit 45, and the address memory 47 may be omitted if the restart signals of the position detection circuits 45 and 46 are always output simultaneously.

  FIG. 2A is a schematic plan view of a main part showing a sector in the optical disc 32. FIG. 2B is a schematic diagram showing addresses in the buffer memory 13. Each sector Sn + 1, Sn, Sn-1, Sn-2... Sn-m shown in FIG. 2 (a) corresponds to each address An + 1, An, An-1, An shown in FIG. -2 …… Supports An-m.

  In the recording operation, the input data of each address is read from the buffer memory 13 in the order of addresses An-m.fwdarw.An-2.fwdarw.An-1.fwdarw.An, and the recording data modulated by the encoder 14 is converted into the sector Sn. Recording is performed on each sector of the optical disk 32 in the order of -m →... Sn-2 → Sn-1 → Sn. Assume that the buffer underrun determination circuit 20 determines that a buffer underrun has occurred in the buffer memory 13 at an arbitrary address An during the recording operation.

  Then, the recording data of the sector Sn corresponding to the address An is recorded on the optical disc 32, but the recording of the recording data is interrupted from the middle of the synchronization pattern of the data of the sector Sn + 1 corresponding to the next address An + 1. Is done. The address memory 47 stores and holds the address An. The address memory 48 stores and holds the ATIP address demodulated from the recording data of the sector Sn.

  Thereafter, when the buffer underrun determination circuit 20 determines that the state in which the buffer underrun has occurred is avoided, the buffer underrun occurs and the recording operation is interrupted to start from the sector Sn of the optical disk 32. It returns by a predetermined number of sectors (here, m sectors), and the reproducing operation at the time of resuming recording is started from the returned sector Sn-m.

  When the reproduction operation is resumed when recording is resumed, the predetermined number of sectors (m sectors) is determined from the address An of the recorded data in the buffer memory 13 at the time when the recording operation is interrupted due to the occurrence of buffer underrun. Is returned by a predetermined number of addresses corresponding to (m addresses), and the input data of each address is read from the buffer memory 13 sequentially from the returned address An-m, and is modulated by the encoder 14 into recording data.

  The signal synchronization circuit 42 synchronizes the recording data output from the encoder 14 with respect to the recording data of the sectors Sn-m to Sn already recorded on the optical disc 32. After that, when the address of the input data read from the buffer memory 13 in the reproducing operation when resuming recording coincides with the address An stored in the address memory 47, a restart signal is output from the position detection circuit 45. Further, when the ATIP address demodulated by the ATIP demodulator circuit 10 and the ATIP address demodulated from the recorded data of the sector Sn stored in the address memory 48 in the reproduction operation upon resuming recording coincide with each other, the position detection circuit 46 resumes. A signal is output. When the restart signals from the position detection circuits 45 and 46 are simultaneously output, the retry determination circuit 44 restarts the recording operation.

  As a result, the recording data of the next sector Sn + 1 can be recorded from the position where the sector Sn seamlessly continues with respect to the sector Sn at the time when the recording operation is interrupted due to the occurrence of buffer underrun. it can. The predetermined number of sectors (m sectors) is synchronized with the time T1 required for the spindle servo circuit 3 to control the spindle motor 2 and the head servo circuit 6 to control the optical head 4 and the signal synchronization circuit 42. Taking into account the time T2 required to take, it is sufficient to set the number of sectors such that each time T1, T2 can be taken sufficiently, for example, m = 10-30. Note that, as the recording speed in the CD-R drive 1 increases to 4 times or 8 times the standard speed, the times T1 and T2 become longer, so the predetermined number of sectors must be set to a large value.

  In addition, this invention is not limited to the said embodiment, You may change as follows, and even in that case, the effect | action and effect equivalent to or more than the said embodiment can be acquired.

  (1) In the above embodiment, the rotation of the constant linear velocity (CLV) type optical disk 32 is controlled so that the crystal oscillation circuit 18 generates the operation clock output from the system clock generation circuit 41 during the recording operation. A reference clock generated based on the oscillation signal is used. However, the present invention may be applied to the case where rotation of an optical disc 32 of a constant angular velocity (CAV) type is controlled. In this case, a clock generated in synchronization with the wobble component extracted by the wobble decoder 9 may be used as the operation clock output from the system clock generation circuit 41 during the recording operation.

  (2) In the above embodiment, the access control circuit 19, the buffer underrun determination circuit 20, the recording control circuit 21, and the system control circuit 22 are configured by separate electronic circuits. , RAM and the like may be replaced with a microcomputer composed of hardware, and the functions of the respective circuits may be realized by various arithmetic processes executed by the microcomputer.

  (3) The above embodiment is applied to a CD-R drive that uses a write-once type optical disk. However, the recording medium can record data again and again (for example, an optical disk of the CD-RW standard). The present invention may be applied to a data recording apparatus (for example, a CD-RW drive, an MD drive, etc.) using an MD standard magneto-optical disk. In this case, since it is possible to prevent the occurrence of a buffer underrun error, data recorded before the buffer underrun occurs is not wasted, and the time required for the recording operation can be shortened. it can.

1 is a block circuit diagram showing a schematic configuration of a CD-R drive of an embodiment embodying the present invention. FIG. 2A is a schematic plan view showing a main part of a sector in the optical disc according to the embodiment. FIG. 2B is a schematic diagram illustrating addresses in the buffer memory according to the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 CD-R drive 2 Spindle motor 3 Spindle servo circuit 4 Optical head 5 RF amplifier 6 Head servo circuit 7 Decoder 8 Subcode demodulation circuit 9 Wobble decoder 10 ATIP demodulation circuit 11 External connection terminal 12 Interface 13 Buffer memory 14 Encoder 15 Encoder internal RAM
DESCRIPTION OF SYMBOLS 16 Laser drive circuit 18 Crystal oscillation circuit 19 Access control circuit 20 Buffer underrun determination circuit 21 Recording control circuit 22 System control circuit 31 Personal computer 32 Optical disk 41 System clock generation circuit 42 Signal synchronization circuit 43 Interruption / resumption circuit 44 Retry determination circuit 45 , 46 Position detection circuit 47, 48 Address memory

Claims (2)

A control device for controlling interruption / resumption of data writing when data stored in a buffer memory is repeatedly written to a recording medium by irradiating a laser beam at a high level or a low level, and when the data writing to the recording medium is interrupted The address memory for storing at least one of the address indicating the position on the recording medium corresponding to the interruption position and the address indicating the position on the buffer memory corresponding to the interruption position, and the data written on the recording medium are read. A restart circuit for instructing restart of data writing to the recording medium based on the address stored in the address memory,
When it is determined that a buffer underrun has occurred due to empty data capacity stored in the buffer memory, the laser irradiation gives a data write interruption instruction during a low level period,
When it is determined that a state in which a buffer underrun has occurred has been avoided after the interruption instruction, the resumption circuit performs the laser irradiation in a low level period so as to be continuous with the recording data recorded immediately before the recording interruption. A control device that instructs resumption of data writing to a recording medium. A control device for a data recording device that stores input data input from an external device in a buffer memory and performs data recording by irradiating a recording medium with a laser according to the input data,
During a recording operation on the recording medium, if a state in which a buffer underrun occurs due to empty data capacity stored in the buffer memory is detected, the power level of the laser beam applied to the recording medium is reduced. The recording operation is interrupted at
After that, when a situation in which buffer underrun occurs is avoided, the recorded data is generated from the input data before the recording interruption stored in the buffer memory while reproducing the recording data recorded before the recording interruption from the recording medium. And a control device for resuming the recording operation at a timing when the power level of the laser beam applied to the recording medium is reduced to be continuous with the recording data recorded immediately before the recording interruption.