AM335X USB_8 DRVVBUS level change IRQ

Is this a follow-up question to AM335X USB0_DRVVBUS automatically switched to low? If so, DRVVBUS 1->0 change is due to over current, there will be VBUS_ERROR interrupt. Please look for MUSB_INTR_VBUSERROR in the linux musb driver.

Hi, Liu Bin,

Yes, this is a follow-up to 35X USB0_DRVVBUS automatically switched to low. We have got the solution to switch on the DRVVBUS. We just need a solution to automatically catching the DRVVBUS change through IRQ. our S/W tried to use the VBUS_ERROR interrupt USB_7(Interrupt status for VBUS andlt VBUS valid threshold), but looks deosn't help.

Peng,

What do you mean by 'doesn't help'? You don't see VBUS_ERROR interrupt when DRVVBUS is turning to low? How much capacitor do you have on VBUS line? It has to be minimum 120uF.

Another option is to use a GPIO connecting to VBUS line via a FET, as an interrupt source. Then when VBUS changes 0->1, or 1->0, you will have a GPIO interrupt, depending on its configuration.

In which document can I find this  this 120uF minimum capacitor on VBUS line?

S/W tried using VBUS_ERROR IRQ, but could not receive the interrupt when DRVVBUS was changed to low.

I think with H/W change, S/W can use GPIO IRQ to detect DRVVBUS change.

120uF is defined in USB2.0 Specs, Section 7.2.4.1.