Apple Inc.

Suhas Kumar Suvarna Ramesh

Robert E Jeter

Rakesh L Notani

Manu Gulati

Kai Lun Hsiung

John H Kelm

Venkata Ramana Malladi

Naveen Kumar Korada

Matthew R Johnson

Alma L Juarez Dominguez

Mohammad Rizwan

Thomas H Huang

Systems, methods and mechanisms for efficiently calibrating memory signals. In various embodiments, a computing system includes at least one processor, a memory and a power manager. The power manager generates and sends updated power-performance states (p-states) to the processor and the memory. Logic within a memory controller for the memory initializes a first timer corresponding to a first p-state of the multiple p-states to indicate a duration for skipping memory calibration. The logic continues to update the first timer while transferring data with the memory using operating parameters of the first p-state. When the memory is not using operating parameters of the first p-state, the logic prevents updates of the first timer. When the power manager determines to transition the memory from the first p-state to a second p-state, and the second timer for the second e-state has not expired, the logic prevents calibration of the memory.

Filtering memory calibration

Techniques are disclosed relating to feedback-controlled oscillators (e.g., phase-locked loops) arranged in two or more levels. In some embodiments, in a relatively higher-frequency mode, a first level feedback-controlled oscillator provides reference signals to one or more second level feedback-controlled oscillators that in turn generate output clock signals to clock sequential circuitry. In some embodiments, in a relatively lower-frequency mode, the first level feedback-controlled oscillator bypasses the second level feedback-controlled oscillators and provides output clock signals directly to sequential circuitry (without using any intervening feedback-controlled oscillators).

Hierarchical feedback-controlled oscillator techniques

Growing community of inventors

Santa Clara, CA, United States of America

Suhas Kumar Suvarna Ramesh