Abstract: A system for determining whether a focus servo system is in focus or out of focus (i.e. open) is disclosed. A sum signal can be compared with a threshold value. If the sum signal is below the threshold value, then a focus open condition (i.e., out-of-focus) can be indicated. In some embodiments, a focus open condition is indicated where the sum signal remains below the threshold value for a predetermined period of time.

Abstract: A system and method for dynamically re-calibrating an optical disc drive during operation is provided. The optical media includes a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The system can attempt several increasing levels of effort to recalibrate the disc drive until the disc drive reaches a desired level of performance, or the recalibration effort levels are exhausted. During each level of recalibration effort, various calibration values are determined for the optical media and the servo actuator, along with a notch frequency for a notch filter; a focus actuator offset; a tracking actuator offset; a focus control loop gain; and a tracking control loop gain. The optical media disc is divided into zones, and zone calibration tables for each of the zones are generated. Each zone is recalibrated using the corresponding zone calibration table.

Abstract: An anti-skate algorithm in a tracking servo system of an optical disk drive is described. The anti-skate algorithm prevents skating during close of the tracking servo system by allowing the tracking servo system to close on a tracking error signal with an appropriate slope.

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, 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 storing calibrated optical parameters is presented. In some embodiments, calibrated optical parameters are stored in place of stored parameters. In some embodiments, averages between the calibrated operating parameters and stored optical parameters are stored. In other embodiments, the stored optical parameters are allowed to vary only by a maximum amount. In some embodiments, if the calibrated parameters vary by more than threshold values, then the calibrated parameters are not stored.

Abstract: A system for controlling laser power in an optical disc drive is provided including instructions operable to reduce the laser power while seeking over tracks in the optical media, to increase the laser power when reading from or writing to the optical media, and to decrease the laser power when turning tracking off. The optical media includes a premastered area that cannot be overwritten and a user-writeable area that can be overwritten.

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 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 system and method for controlling operation of a disc drive for optical media. The optical media includes a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The disc drive determines the position of an actuator arm in relation to the grooved and pitted areas, and enters a physical sector address (PSA) idle state, where no attempts to read physical address sectors (PSAs) are made when tracking or focus are not active. The drive transitions from the PSA idle state to a PSA enable state when tracking becomes active, and to a PSA locked state where PSAs can be read when both focus and tracking are active. The drive also re-attempts to acquire a PSA when the PSA cannot be read within a predetermined time period. The re-attempt includes toggling between control system settings appropriate for pits and settings appropriate for grooves.

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 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 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 present invention includes starting the operation of a motor including windings and a rotor; placing the motor in a first operational state; driving the motor from the first operational state to a second operational state; and sensing a variation in an electrical waveform induced by driving of the motor to determine a cycle period from which the speed of the motor can be determined.

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 read a physical sector address (PSA) from an optical medium, calculate a table index based on the PSA, enter a lookup table module to acquire reference data, and maintain a constant data rate transfer from the optical medium for a range of PSAs.

Abstract: A tracking servo system with a feed-forward control loop is presented. Periodic variations in a control signal can be detected. These periodic variations can be added into the control signal to form a new control signal so that on subsequent cycles the control signal does not include the periodic variations.

Abstract: A control system controls the spin speed of optical media in an optical disc drive, wherein the optical media comprises a premastered area that cannot be overwritten and a user-writeable area that can be overwritten. The control system stops and starts the spinning of the optical media, and controls the spin speed and the direction of spin. The control system also determines whether the commanded spin speed has been attained within a specified time period, and maintains the commanded spin speed. An event issues when the commanded spin speed was not attained within a specified time period, when a problem is detected while attempting to maintain the commanded spin speed, and when the optical media stops spinning. A laser in the disc drive is turned off when spin is turned off.

Abstract: A method for automatically calibrating gain parameters of a servo control including a track position detector for a computer disk drive. The method generally comprises the step of encoding AB bursts on at least one special calibration track of a disk surface in accordance with a known off center pattern signal having a preselected frequency. Servo correction number information is also encoded on the calibration track to compensate for the off center pattern of the AB bursts. A digital signal processing technique is performed on a correction signal derived from the AB bursts and servo correction number information to detect a residual signal at the preselected frequency of the off center pattern signal. The gain of the track position detector is thereafter adjusted to minimize the magnitude of the residual signal.