USB OTG2 host mode VBUS toggles continuously

[prabhatkumar]

Hi,

In host mode, custom board USB OTG port detects the device and the USB_OTG2_ID pin goes low but the USB_OTG2_PWR pin from CPU is toggling from 0V to 3.2V continuously whenever a device (flash drive) is connected to the host. I checked USB_OTG2_OC pin and there is no over current issue either.

Can someone please explain why USB_OTG2_PWR continuously toggles when the board is in host mode?

Thanks

[igorpadykov]

Hi Prabhat

this looks like board hardware/layout error, as
USB_OTG2_PWR is connected on i.MX6UL EVK (SPF-28617.PDF)
to GPIO_2 pad and its power domain NVCC_GPIO can not exceed
datasheet requirements 3.6V, defined in Table 11. Operating Ranges i.MX6UL Datasheet
http://cache.freescale.com/files/32bit/doc/data_sheet/IMX6ULCEC.pdf

Best regards
igor
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[prabhatkumar]

Hi Igor,

My apologies, it is toggling between 0 and 3.2V. USB_OTG2_PWR is connected to A16 (ENET2_TX_DATA1) pin and it is operating in ALT8 mode. According to the datasheet, It should work as well when connected to ENET2_TX_DATA1 pad.