am3352 usb detect

Ahn

Intellectual 1000 points

Hi,

My target board has an AC power supply and battery.

When AC power is turned on, USB is properly detect.

( boot on AC power turned on status )

But, after AC power turn off(VBUS : 3.7V) -> on(VBUS : 5V), USB didn't detected.

How to reset the USB module?

/proc/driver/musb_* doesn't exist.

My environment:

linux-3.14.26-g2489c02

kernel config :

7457.Config.txt

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

If VBUS falls to +3.7V it's quite normal that USB detection will fail. The USB 2.0 controller is in session when either it senses a voltage >= +4.4V on the USBx_VBUSIN pin and the controller sets its DEVCTL[SESSION] bit field or when the firmware sets the DEVCTL[SESSION] bit; assuming that it will be operating as a host.

0 Ahn over 9 years ago in reply to Biser Gatchev-XID

Intellectual 1000 points

Hi,

VBUS : 3.7V

- usb detect fail is OK.

VBUS : 3.7V -> 5V

- usb detect fail is not OK.

0 Biser Gatchev-XID over 9 years ago in reply to Ahn

TI__Guru**** 393215 points

What I can say is that your USB Host port design does not follow the design recommendations: processors.wiki.ti.com/.../AM335x_Schematic_Checklist You don't have a VBUS power switch controlled by USB_DRVVBUS. Also you must have a capacitor >=120uF on VBUS close to the connector.

0 Biser Gatchev-XID over 9 years ago in reply to Ahn

TI__Guru**** 393215 points

About:

VBUS : 3.7V - usb detect fail is OK.
VBUS : 3.7V -> 5V - usb detect fail is not OK.

Can you describe this in more detail? The USB team cannot understand what you are trying to say.

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am3352 usb detect