USB Enable Signal Still Invalid

can chen

Hi,

I test USB interface on custom board is not work, Mistral board is work normal,. According to Mistral board's circuit design. I test level through multimeter.

The result is the pins of 2 and 3 is 5V, but The pin 4 is still low level, so the pins of 6,7and 8 is still low level, this cause USB not work normal.

The normal condition is the pins 4,6,7,and 8 is 5V. So,I want to konw USBB0_DRV_VBUS is controled by what, and find that:

As the over illustration, this level is controled by A8.

I want to pulled USBB0_DRV_VBUS signal high levle in linux kernel to test that whether the signal is 5V?But I cannot find the control function is linux kernel.May I idea is right? Can you tell me the contorl funtion in which directory?

Regards,

Chen

over 12 years ago

0 Vladimir-XID over 12 years ago

TI__Genius 11470 points

Hello,

When used as USB0_DRVVBUS mode this pin is not software controlled, instead of this this it is controlled by the MUSB0 hardware core (the driver controlling MUSB0 is located in drivers/usb/musb/).

To achieve proper functionality it has to be configured in MUX MODE 0 - USB0_DRVVBUS otherwise it will operate as GPIO7, and respectively must be set in output mode.

Thank you.

Vladimir