Parameter updating methods and systems for optical disc accessing

• US 20070076552A1
• Filed: 10/04/2005
• Published: 04/05/2007
• Est. Priority Date: 10/04/2005
• Status: Abandoned Application

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Chen, Chih-Ching, Chao, Ming-Yang
• Application Number:
  US11/243,066
• Publication Number:
  US 20070076552A1
• Time in Patent Office: Days
• US Class Current: 369/53.300
• CPC Class Codes: G11B 27/24 by sensing features on the record carrier other than the transducing track ; sensing signals or marks recorded by another method than the main recording
• CPC Class Codes: G11B 7/00456 Recording strategies, e.g. pulse sequences G11B7/0062 takes precedence

Abstract

Methods and systems for dynamically updating velocity dependent parameters during optical disc accessing are provided. A velocity estimator estimates a current velocity of a rotating disc. A storage unit stores a plurality set of parameters, each set corresponds to a preset velocity, and a register stores velocity dependent parameters that are currently used for data recording. A batch controller retrieves a set of parameters from the storage unit according to the current velocity estimated by the velocity estimator, and updates the velocity dependent parameter stored in the register using the parameters retrieved from the storage unit.

Claims

1. An optical disc accessing system, comprising:

a velocity estimator, estimating a current velocity of a rotating disc;

a storage unit, storing at least a set of parameters, wherein each set of parameters corresponds to a preset velocity;

a register, storing at least a velocity dependent parameter; and

a batch controller, retrieving a set of parameters from the storage unit according to the current velocity estimated by the velocity estimator, and updating the velocity dependent parameter stored in the register using the parameters retrieved from the storage unit.

2. The optical disc accessing system according to claim 1, further comprising a write strategy wave generator coupled to the register, generating a laser power control signal according to the velocity dependent parameter stored in the register.

3. The optical disc accessing system according to claim 2, wherein the register is a write strategy information buffer, storing write strategy parameters and laser power for disc recording.

4. The optical disc accessing system according to claim 1, further comprising a servo circuit coupled to the register, executing servo control in accordance with the velocity dependent parameter stored in the register.

5. The optical disc accessing system according to claim 4, wherein the servo control executed by the servo circuit comprises focusing servo control, tracking servo control, seeking servo control, and spindle control.

6. The optical disc accessing system according to claim 1, further comprising a pre-amplifier circuit coupled to the register, wherein coefficients of the pre-amplifier circuit is determined in accordance with the velocity dependent parameter stored in the register.

7. The optical disc accessing system according to claim 1, wherein the parameters stored in the storage unit are differentiated values, and the batch controller updates the velocity dependent parameter by adding or subtracting the differentiated value to/from the original velocity dependent parameter stored in the register.

8. The optical disc accessing system according to claim 1, wherein the batch controller retrieves a set of parameters and updates the velocity dependent parameter accordingly when the batch controller determines that the current velocity reaches another preset velocity which corresponds to a different set of parameters.

9. The optical disc accessing system according to claim 1, wherein the velocity estimator comprises a velocity detector detecting a linear velocity of the rotating disc.

10. The optical disc accessing system d according to claim 1, wherein the velocity estimator comprises a location detector which estimates the current velocity according to a current accessing location of the disc.

11. The optical disc accessing system according to claim 10, wherein the location detector determines the current accessing location based on a physical address extracted from an Absolute Time in Pre-groove (ATIP) time code, Land Pre-pit (LPP) bits, or Address in Pre-groove (ADIP) bits.

12. The optical disc accessing system according to claim 1, wherein the velocity estimator outputs an ATIP time code extracted from the disc as the current velocity, each set of parameters stored in the storage unit corresponds to an ATIP time code, and the batch controller retrieves a set of parameters from the storage unit based on the extracted ATIP time code.

13. The optical disc accessing system according to claim 1, wherein the storage unit is a Dynamic Random Access Memory (DRAM) storing a write strategy table, and each entry of the write strategy table comprises a set of parameters and its corresponding velocity.

14. The optical disc accessing system according to claim 1, wherein the disc is rotated at a constant angular velocity (CAV).

15. The optical disc accessing system according to claim 1, wherein the parameters stored in the storage unit comprises instruction codes and instruction numbers, each defining a bank, address, or data to be written into the register.

16. The optical disc accessing system according to claim 15, wherein the batch controller comprises:

a first in first out (FTIFO) buffer, buffering a write command for switching the velocity dependent parameter stored in the register; and

a batch executor, decoding the instruction codes retrieved from the storage unit and generating a corresponding command for updating the register.

27. The dynamic parameter updating method according to claim 1, wherein the parameters stored in the table comprise instruction codes and instruction numbers, each defining a register and related address or data to be written into the register.

28. The dynamic parameter updating method according to claim 27, further comprising:

buffering a write command for switching the velocity 41 dependent parameter stored in the register;

decoding the retrieved instruction codes; and

generating a corresponding command for updating the register based on the decoded instruction codes.

17. A dynamic parameter updating method for optical disc accessing, comprising:

estimating a current velocity of a rotating disc;

providing a table storing a set of parameters corresponding to each preset velocity;

retrieving a set of parameters from the table according to the current velocity;

updating a velocity dependent parameter stored in a register with the retrieved parameters; and

performing disc accessing based on the velocity dependent parameter stored in the register.

18. The dynamic parameter updating method according to claim 17, further comprising generating a laser power control signal in accordance to the velocity dependent parameter, and emitting a laser beam for disc accessing according to the laser power control signal.

19. The dynamic parameter updating method according to claim 18, wherein the velocity dependent parameter comprises write strategy parameters and laser power for disc recording.

20. The dynamic parameter updating method according to claim 17, further comprising executing servo control in accordance with the velocity dependent parameter.

21. The dynamic parameter updating method according to claim 20, wherein the servo control comprises focusing servo control, tracking servo control, seeking servo control, and spindle control.

22. The dynamic parameter updating method according to claim 17, wherein the velocity dependent parameter is updated according to the retrieved parameters when the current velocity reaches another preset velocity which corresponds to a different set of parameters.

23. The dynamic parameter updating method according to claim 17, wherein the current velocity is estimated by detecting a linear velocity of the rotating disc.

24. The dynamic parameter updating method according to claim 17, wherein the current velocity is estimated according to a current accessing location of the disc.

25. The dynamic parameter updating method according to claim 24, wherein the current accessing location is determined based on a physical address extracted from an ATIP (Absolute Time in Pre-groove) time code.

26. The dynamic parameter updating method according to claim 17, wherein the disc is rotated at a constant angular velocity (CAV).