SNLS757B June 2024 – November 2024 TUSB2E221
PRODMIX
Optional host repeater auto-resume is supported by the TUSB2E221 in L1/L2 by driving Resume K at D+/D- until SOResume is received from eDSPr. In addition, the TUSB2E221 eUSPh will hold Remote Wake line state until SORresume is received from eDSPr.
This auto-resume feature provides the host controller extra time to exit low power state and issue SOResume while the TUSB2E221 UDSP drives resume within 1ms (TURSM) hub resume timing requirement. To take advantage of this low power feature, the host controller implements low power mechanism to detect wake on eDSPr lines while host controller is in low power state.
This auto-resume feature is not required if host controller is capable of initiating SOResume within 1ms of detecting Remote Wake on eDSPr.
This auto-resume ECR mode is disabled when L2 interrupt mode is enabled. When L2 interrupt mode is enabled, resume K at D+/D- is still driven when Remote wake is detected on UDSP but eUSPh is held at SE0 instead of in Remote Wake state. See the L2 State Interrupt Modes section for more details.