US 12,293,808 B2
Memory subsystem calibration using substitute results
Robert E. Jeter, Santa Clara, CA (US); Rakesh L. Notani, Santa Clara, CA (US); Kai Lun Hsiung, Fremont, CA (US); Venkata Ramana Malladi, Santa Clara, CA (US); Rahul Ranjan, Santa Clara, CA (US); and Naveen Kumar Korada, Pleasanton, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Aug. 24, 2023, as Appl. No. 18/455,385.
Application 18/455,385 is a continuation of application No. 17/646,741, filed on Jan. 3, 2022, granted, now 11,776,597.
Application 17/646,741 is a continuation of application No. 16/986,116, filed on Aug. 5, 2020, granted, now 11,217,285, issued on Jan. 4, 2022.
Prior Publication US 2024/0062792 A1, Feb. 22, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G11C 7/22 (2006.01); G06F 11/10 (2006.01); G11C 7/10 (2006.01)
CPC G11C 7/22 (2013.01) [G06F 11/1076 (2013.01); G11C 7/10 (2013.01); G11C 2207/2254 (2013.01)] 21 Claims
OG exemplary drawing
 
1. An apparatus comprising:
a memory controller, wherein the memory controller is configured to communicate with a memory via a plurality of signal paths, and wherein the memory controller includes a calibration circuit, wherein the calibration circuit is configured to:
perform a first calibration that includes activating each of the plurality of signal paths to determine respective eye patterns for signal paths in the plurality of signal paths; and
perform a second calibration subsequent to the first calibration, wherein the second calibration comprises activating a first subset of the plurality of the signal paths to determine update respective eye patterns for signal paths in the first subset, and, for signal paths of a second subset different from the first subset, determine respective updated eye patterns based on information obtained during the first calibration, wherein the second calibration is performed without activating the signal paths of the second subset.