US 10,890,939 B2
Recovery of reference clock on a device
Bradley Allan Lambert, Austin, TX (US); Bruce E. Duewer, Round Rock, TX (US); David Hisky, Leander, TX (US); Marc J. Kobayashi, Austin, TX (US); and Michael A. Kost, Cedar Park, TX (US)
Assigned to Cirrus Logic, Inc., Austin, TX (US)
Filed by Cirrus Logic International Semiconductor Ltd., Edinburgh (GB)
Filed on Mar. 20, 2018, as Appl. No. 15/926,643.
Claims priority of provisional application 62/489,196, filed on Apr. 24, 2017.
Prior Publication US 2018/0307293 A1, Oct. 25, 2018
Int. Cl. G06F 1/04 (2006.01); G06F 1/10 (2006.01); G06F 13/38 (2006.01); G06F 1/3215 (2019.01); G06F 1/12 (2006.01); G06F 13/42 (2006.01); G06F 1/3234 (2019.01); G06F 1/08 (2006.01)
CPC G06F 1/10 (2013.01) [G06F 1/12 (2013.01); G06F 1/3215 (2013.01); G06F 1/3278 (2013.01); G06F 13/385 (2013.01); G06F 13/4265 (2013.01); G06F 13/4278 (2013.01); G06F 1/08 (2013.01); G06F 2213/0042 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A method for generating a not-yet (NYET) signal in a recovered reference system for recovering a device reference clock on a device, wherein the NYET signal indicates that the device is not yet ready for transition into a low power mode, in order to improve a quality of a recovered reference clock representative of a host reference clock of a host communicatively coupled to the device, the method comprising:
detecting receipt of start-of-frame markers from the host to the device;
responsive to detecting receipt of the start-of-frame markers, determining whether a condition for NYET generation is being met;
responsive to the condition for NYET generation being met, generating the NYET signal to cause the host to continue generating the start-of-frame markers; and
responsive to the condition for NYET generation not being met, causing the device to generate an acknowledge signal for transition of the device into the low power mode.