US 12,124,399 B2
Universal serial bus (USB) controller, method of operating a USB controller, and machine vision system
Karthik Sivaramakrishnan, Bangalore (IN); Hamid Khodabandehlou, Milpitas, CA (US); Godwin Arulappan, Sunnyvale, CA (US); Jagadeesan Rajamanickam, San Jose, CA (US); Manaskant Dipakkumar Desai, Bangalore (IN); and Nimish Thakkar, Bangalore (IN)
Assigned to CYPRESS SEMICONDUCTOR CORPORATION, San Jose, CA (US)
Filed by Cypress Semiconductor Corporation, San Jose, CA (US)
Filed on Jan. 5, 2023, as Appl. No. 18/093,565.
Prior Publication US 2024/0232124 A1, Jul. 11, 2024
Int. Cl. G06F 13/14 (2006.01); G06F 13/42 (2006.01); H04N 23/66 (2023.01)
CPC G06F 13/4291 (2013.01) [H04N 23/66 (2023.01); G06F 2213/0042 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A universal serial bus (USB) controller, comprising:
a USB interface configured to receive an isochronous timestamp packet (ITP) from a host device, the ITP including a current time value provided by the host device and a delay value associated with each hub through which the ITP passed;
controller hardware configured to initiate a counter, send a link delay measurement (LDM) link management packet (LMP) request to a nearest upstream hub, store a first timestamp that corresponds to when the LDM LMP request was sent, receive an LDM LMP response from the nearest upstream hub, and store a second timestamp that corresponds to when the LDM LMP response was received; and
controller software configured to calculate a link delay between the USB controller and the nearest upstream hub based on the first and second timestamps and delay information included in the LDM LMP response, and adjust a value of the counter based on the calculated link delay.