AM335x how to handle USB DRVVBUS low

Kummi

Other Parts Discussed in Thread: AM3352

Hi,

I am sorry if this is a repeated question.
In our customer's application, AM3352's USB is used as a Host to connect a USB device.
Sometimes there will a drop in the VBUS voltage(<4.4V) when the USB is Device is connected to the host
and the DRVVBUS will be LOW even after re-connecting the Device.

We would like to know what procedure should be followed to recover the connection.
Should we add any software handler or will the hardware take care of the re-connection?
Note: This application is using StarterWare drivers.

Please let us know your suggestions or any reference on how to handle VBUS low voltage (Low DRVVBUS).

Best Regards
Kummi

over 9 years ago

0 Kummi over 9 years ago

Mastermind 6220 points

Hi,

After searching the forum, found that we need to re-initialize the USB host controller.
Could you please confirm that Re-initializing USB port is the proper procedure
when there is a drop in VBUS voltage(<4.4V) i.e VBUS error　?

Starterware USB host driver has below VBUS error handler.

case HCD_VBUS_ERROR:
{

// Disable USB interrupts.
IntSystemDisable(g_USBInstance[ulIndex].uiInterruptNum);

// Reset the controller.
USBReset(g_USBInstance[ulIndex].uiSubBaseAddr);

// Re-initialize the HCD.
USBHCDInitInternal(ulIndex, g_sUSBHCD[ulIndex].pvPool,
g_sUSBHCD[ulIndex].ulPoolSize);

}

Best Regards
Kummi

0 Lalindra Jayatilleke over 9 years ago in reply to Kummi

TI__Mastermind 30365 points

Kummi,

I have requested someone with a better understanding of the VBUS error to comment.

Thanks for your patience.

Lali

0 Kummi over 9 years ago in reply to Lalindra Jayatilleke

Mastermind 6220 points

Thank you...Please let me know if there is any advice.

0 Kummi over 9 years ago in reply to Kummi

Mastermind 6220 points

Hi Lali,

Waiting for the reply!
Please let me know if there is any suggestions on this topic.

Best Regards
Kummi

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AM335x how to handle USB DRVVBUS low