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AlanCLTan
Occasional Contributor
1 month agoHi dpeng,
Let me understand further on your setup:
- CPEN routed to a VBUS power switch enable (active‑high)
- RESET# of the USB3320 driven by HPS_GPIO0 (active‑low)
Is that correct?
Could you confirm the checklist below:
- Confirm the 5 V input to the VBUS power switch is present.
- Verify the switch enable pin is active-high and connected to CPEN directly.
- Verify the reference clock to USP3320 (26MHz) is present and stable.
- Scope the ULPI CLK pin from the PHY (usually 60 MHz output to the MAC).
- Also check that ULPI I/O voltage rails (1.8 V or 3.3 V) are correct.
- For OTG micro‑AB, ID grounded: A‑device (host); ID floating: B‑device (peripheral). If the ID pin is floating, the PHY may not try to source VBUS.
Best regards,
Alan