System and method for controlling tracking and seeking in an optical disc drive
View Patent ↗A control system for controlling tracking and seeking in an optical disc drive for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The control system determines whether an optical pickup unit is over the premastered or the writeable areas of the optical media by measuring peak to peak amplitude of a tracking error signal. Gains and calibration values are selected based on whether an optical pickup unit is over the premastered or the writeable areas of the optical media. Reading from and writing to the optical media is disabled while jumping tracks. Control of jumping tracks on the optical media includes controlling: jumping a single track on the optical media; jumping a specified number of tracks every specified number of revolutions of the optical media; auto jumpbacks, and jumping in forward or reverse directions. Parameters for controlling jumps include at least one of: jump type, number of tracks to jump, time delay between track jumps, number of revolutions of the optical media between jumps, and whether it is not safe to read from or write to the optical media. The control system performs long seeks by predicting whether the tracking actuator arm will be positioned over the premastered area or the writeable area at the end of the long seek, and to load calibration parameters corresponding to the type of media over which the tracking actuator arm will be positioned at the end of the long seek.
1. An apparatus for controlling tracking and seeking in an optical disc drive for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten, comprising:
an optical pick-up unit;
an analog-to-digital converter coupled to receive signals from detectors in the optical pick-up unit and provide digital signals;
a digital signal processor coupled to receive the digital signals and calculate a tracking error signal, the digital signal processor calculating a control signal for driving a servo system to reduce the calculated tracking error signal; the servo system including:
means for turning tracking on and off; and
means for jumping tracks on the optical media.
2. The apparatus, as set forth in claim 1 , further comprising means for transitioning from a tracking idle state to a tracking turn on state when a tracking turn on servo command is received.
3. The apparatus, as set forth in claim 1 , further comprising means for entering a tracking illegal state if focus is not active.
4. The apparatus, as set forth in claim 1 , further comprising means for selecting gain and calibration values based on whether the optical pickup unit is over the premastered or the writeable areas of the optical media.
5. The apparatus, as set forth in claim 1 , further comprising means for determining whether the optical pickup unit is over the premastered or the writeable areas of the optical media.
6. The apparatus, as set forth in claim 1 , wherein the means for determining whether the optical pickup unit is over the premastered or the writeable areas of the optical media comprises means for measuring the peak to peak amplitude of the tracking error signal.
7. The apparatus, as set forth in claim 1 , further comprising means for delaying transition to a tracking active state to allow time for control system parameters to be initialized.
8. The apparatus, as set forth in claim 1 , further comprising means for jumping a single track on the optical media.
9. The apparatus, as set forth in claim 1 , wherein the means for jumping tracks on the optical media includes at least one of: means for jumping multiple tacks on the optical media; means for jumping a single track on the optical media; means for jumping a specified number of tracks every specified number of revolutions of the optical media; and means for jumping in forward or reverse directions.
10. The apparatus, as set forth in claim 1 , further comprising means for disabling reading from and writing to the optical media while jumping tracks.
11. The apparatus, as set forth in claim 1 , further comprising means for performing an auto jumpback function.
12. The apparatus, as set forth in claim 11 , wherein parameters for controlling jumps include at least one of: jump type, number of tracks to jump, time delay between track jumps, number of revolutions of the optical media between jumps, and whether it is not safe to read from or write to the optical media.
13. The apparatus, as set forth in claim 11 , further comprising means for generating a bias value for a tracking arm actuator, wherein the bias value can be used to provide a low frequency tracking control effort (TCE) and to handle high frequency TCE.
14. The apparatus, as set forth in claim 1 , further comprising means for generating a status indicator of whether a track jump was successful, wherein the status indicates at least one of: bad track, bad jump, good track, and good jump.
15. The apparatus, as set forth in claim 1 , further comprising means for performing long seeks.
16. The apparatus, as set forth in claim 15 , further comprising means for predicting whether a tracking actuator arm will be positioned over the premastered area or the writeable area at the end of the long seek, and loading calibration parameters corresponding to the type of media over which the tracking actuator arm will be positioned at the end of the long seek.
17. The apparatus, as set forth in claim 15 , further comprising means for waiting until a time period allotted for performing the long seek expires, and to set a bad seek indicator to indicate whether the long seek failed or completed.
18. The apparatus, as set forth in claim 1 , further comprising means for positioning the optical pickup unit over an area of the optical media containing tracks to be acquired.
19. A method for controlling tracking and seeking in an optical disc drive for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten, comprising:
receiving digitized optical pickup unit signals;
within a digital signal processor, forming a tracking error signal from the digitized optical pickup unit signals;
turning tracking on and off; and
jumping tracks on the optical media.
20. The method, as set forth in claim 19 , further comprising transitioning from a tracking idle state to a tracking turn on state when a tracking turn on servo command is received.
21. The method, as set forth in claim 19 , further comprising entering a tracking illegal state if focus is not active.
22. The method, as set forth in claim 19 , further comprising selecting gain and calibration values based on whether an optical pickup unit is over the premastered or the writeable areas of the optical media.
23. The method, as set forth in claim 19 , further comprising determining whether an optical pickup unit is over the premastered or the writeable areas of the optical media.
24. The method, as set forth in claim 19 , wherein the determining whether the optical pickup unit is over the premastered or the writeable areas of the optical media comprises measuring the peak to peak amplitude of a tracking error signal.
25. The method, as set forth in claim 19 , further comprising delaying transition to a tracking active state to allow time for control system parameters to be initialized.
26. The method, as set forth in claim 19 , further comprising jumping a single track on the optical media.
27. The method, as set forth in claim 19 , wherein the jumping tracks on the optical media includes at least one of: jumping multiple tracks on the optical media; jumping a single track on the optical media; jumping a specified number of tracks every specified number of revolutions of the optical media; and jumping in forward or reverse directions.
28. The method, as set forth in claim 19 , further comprising disabling reading from and writing to the optical media while jumping tracks.
29. The method, as set forth in claim 19 , further comprising performing an auto jumpback function.
30. The method, as set forth in claim 29 , wherein parameters for controlling jumps include at least one of: jump type, number of tracks to jump, time delay between track jumps, number of revolutions of the optical media between jumps, and whether it is not safe to read from or write to the optical media.
31. The method, as set forth in claim 29 , further comprising generating a bias value for a tracking arm actuator, wherein the bias value can be used to provide a low frequency tracking control effort (TCE) and to handle high frequency TCE.
32. The method, as set forth in claim 19 , further comprising generating a status indicator of whether a track jump was successful, wherein the status indicates at least one of: bad track, bad jump, good track, and good jump.
33. The method, as set forth in claim 19 , further comprising performing long seeks.
34. The method, as set forth in claim 33 , further comprising predicting whether a tracking actuator arm will be positioned over the premastered area or the writeable area at the end of the long seek, and loading calibration parameters corresponding to the type of media over which the tracking actuator arm will be positioned at the end of the long seek.
35. The method, as set forth in claim 33 , further comprising waiting until a time period allotted for performing the long seek expires, and to set a bad seek indicator to indicate whether the long seek filed or completed.
36. The method, as set forth in claim 19 , further comprising positioning an optical pickup unit over an area of the optical media containing tracks to be acquired.