Abstract: A control system for an optical disc for optical media with a premastered area that cannot be overwritten and a user-writeable area that can be overwritten, comprises a first processor operable to communicate with a second processor via a status register. The first processor sequences and monitors functions performed in the second processor and the second processor issues an interrupt when an error condition is detected in the second processor. The first processor detects the interrupt, and disables detecting further interrupts until the interrupt is serviced. Servicing the interrupt includes recording the error state and changing focus and tracking parameters based on the error condition detected.

Abstract: A system and method for handling events issued as a result of error conditions in the operation of an optical disc drive include suspending processing of commanded operations in the disc drive while attempting to recover from the error condition. The recovery attempt can include increasing levels of recovery effort, such as dynamically recalibrating various components in the disc drive. The system can also determine whether a previous notice was received for the same error condition. If so, the system can determine whether excessive recovery attempts have been initiated based criteria such as the time between the notices, and/or the number of notices, for the same error condition. The recovery attempts are aborted when they become excessive. If the recovery attempt is successful, the interrupted operation is resumed at the point where the processing was suspended, such as during a write or read command.

Abstract: A calibration of input signal offset in an optical disk drive is presented. The input signal offsets the input signals received from an optical pick-up unit before digitization. In some embodiments, the input signal offset is set such that the digitized input signals are zero when laser power is off. Further, a thermal drift correction is presented.

Abstract: A head load algorithm for an optical disk drive is presented. On startup, the optical media can be spun up. Then an optical pick-up unit can be positioned at an extreme position, for example at the inner diameter, and focus can be closed. The optical pick-up unit then can be incrementally moved away from the extreme position while the tracking error signal is monitored to locate an area of the optical media with tracks. Once the area is located, a tracking servo system can close on one of the tracks.

Abstract: A calibration for a tracking error signal gain in a tracking servo system of an optical disk drive is presented. The calibration determines the peak-to-peak tracking error signal when the tracking servo system is open, calculates a gain factor in response to the peak-to-peak tracking error signal, and calculates a new tracking error signal gain based on the tracking error signal gain and the gain factor. New tracking error signal gains are calculated until the gain factor is approximately one.

Abstract: A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The control system can include a first module for providing a period error, a proportional gain (Kp) and an integration gain (Ki); a second module for operating on the Ki and Kp to provide an output; and a third module for commutating the motor in response to the output.

Abstract: A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The control system can be operable to obtain digital feedback from a spin motor. The present invention includes detecting data representing a position on an optical medium and determining a detection rate; comparing the detection rate to a reference rate to provide an error rate; generating an output command in response to the error rate to provide a drive output which commands a voltage applied to a spin motor to adjust the spin speed of said spin motor.

Abstract: A close tracking algorithm for a tracking servo system is disclosed. The track crossing rate of an optical pick-up unit positioned over an optical media is determined. When the track crossing rate is below a threshold value, then a tracking servo algorithm is enabled. The tracking servo algorithm provides control signals to control an actuator arm that controls the position of the optical pick-up unit over the tracks of the optical media. In some embodiments, the track crossing rate can be determined by monitoring the zero crossings of a tracking error signal derived from optical signals measured in the optical pick-up unit.

Abstract: A media type detector in a tracking and focus servo system is presented. Operating parameters for a first media type are loaded and a peak-to-peak value of a tracking error signal is calculated. Whether the media type is the first media or a second media can then be determined by comparing the peak-to-peak value with a threshold value.

Abstract: A system, method, and apparatus for recovering from performance errors in an optical disc drive is provided for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The system includes instructions operable to detect a problem with at least one of: focus control, tracking control, or spin control when accessing the optical media; instructions operable to save the current state of the disc drive; instructions operable to attempt to recover from the problem; and instructions operable to restore the current state of the disc drive after recovering from the problem.

Abstract: A system and method for controlling spin speed, which includes a module for receiving an indication to make a velocity change from a first RPM to a second RPM. The difference between the first RPM and the second RPM is a predetermined value. The module is operable to rotate an optical medium at a maximum control effort from the first RPM to the second RPM, and rotate the optical medium with a proportional plus integral (P+I) control at the second RPM.

Abstract: A device with an optical disk drive with a digital servo system for controlling tracking or focus in an optical disk driver is presented. A servo system according to the present invention includes an optical pick-up with detectors providing optical signals, an analog processor receiving the optical signals and providing a digital signal, and digital processors receiving the digital signal and providing a control signal that controls the position of the optical pick-up unit. The digital processor executes an algorithm that calculates an error signal, provides amplification and biasing to the error signal, provides filtering for the error signal, and computes the control signal. The error signal can be the focus error signal or the tracking error signal. The device can be any device.

Abstract: A determination of a focus sum threshold in a tracking and focus servo system of an optical disk drive is presented. The focus sum threshold can be determined by moving an optical pick-up unit sinusoidally through a focus position, for example by moving the optical pick-up unit between its closest position to an optical media and its farthest position from the optical media. While moving the optical pick-up unit, a sum signal is monitored. In some embodiments, the sum signal is the sum of signals from a plurality of detectors in the optical pick-up unit. The focus sum threshold is set to a fraction of a peak value of the sum signal.

Abstract: A digital servo system for controlling tracking or focus in an optical disk driver is presented. A servo system according to the present invention includes an optical pick-up with detectors providing optical signals, an analog processor receiving the optical signals and providing a digital signal, and digital processors receiving the digital signal and providing a control signal that controls the position of the optical pick-up unit. The digital processor executes an algorithm that calculates an error signal, provides amplification and biasing to the error signal, provides filtering for the error signal, and computes the control signal. The error signal can be the focus error signal or the tracking error signal.

Abstract: A servo system with a multi-track seek algorithm with an accelerated servo function for regaining a closed tracking loop is presented. Upon completion of a multi-track seek operation, a gain of a tracking servo system is increased for a predetermined number of cycles. In some embodiments, the increased gain leads to a more aggressive track closing operation.

Abstract: A system, method, and apparatus for coordinating tasks in a control system for 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 optical disc drive includes a first processor operable to communicate with a second processor, wherein the first processor includes instructions for performing non-time-critical tasks, and the second processor includes instructions for performing time-critical tasks, such as reading from and writing to optical media in the disc drive. The first processor monitors the status of the time critical tasks in the second processor and transmits commands to perform operations in the second processor. The first processor also controls power mode, manages recovery from errors, controls focus, tracking/seeking, spin, physical sector address (PSA), a laser, adjusts gains, and monitor cartridge load/eject.

Abstract: A method of changing the position of a component controlled by a servo system is disclosed. In accordance with the disclosed invention, the current position and the current control signal corresponding to the current position is determined. A target control signal corresponding to a target position is also determined. A smooth control signal profile is then calculated between the current control signal and the target control signal. The smooth control signal is then applied to move the component form the current position to the target position. In some embodiments, the smooth control signal can be, for example, a half-period sine wave with one extreme at the current control signal and the opposite extreme at the target control signal.

Abstract: A boundary crossing detector in a tracking and focus servo system of an optical disk drive is presented. A tracking error signal can be monitored as an optical pick-up unit of the optical disk drive is allowed to move across an optical media in the optical disk drive. If a peak-to-peak value of the tracking error signal changes by a threshold value, than the boundary crossing can be indicated.

Abstract: A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The control system can include a lookup table module providing a reference period corresponding to each of a physical sector address on an optical medium. The system can further include a drive module configured to sense a BEMF zero crossing occurring in a spin motor. A measurement of two of the BEMF zero crossings can be used to calculate a spin period measurement. The reference period can be compared to the spin period measurement to provide a period error value. The system also includes a controller module for providing a control command to drive the spin motor in response to the period error value.

Abstract: A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The control system can be operable to obtain digital feedback from a spin motor. The present invention includes detecting data representing a position on an optical medium and determining a detection rate; comparing the detection rate to a reference rate to provide an error rate; generating an output command in response to the error rate to provide a drive output which commands a voltage applied to a spin motor to adjust the spin speed of said spin motor.