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STM32F105RB USB current consumption in sleep mode

Question asked by Lim.Shirley on Feb 12, 2014
Latest reply on Feb 12, 2014 by sung.chen_chung
Hi, 

I noticed after USBD_Init(); function has been called, it has increased the current consumption of the MCU. While entering sleep mode, the amount of current consumption caused by USB init is unable to be removed.

By referring to Power Option in USB on-the-go full-speed (OTG_FS) chapter, the power is controlled by these three bits:
1)PHY power down (GCCFG/PWRDWN)
2)A-VBUS sensing enable (GCCFG/VBUSASEN)
3)B-VBUS sensing enable (GCCFG/VBUSASEN)

Therefore I do a function to clear these three bits after USB being removed and before MCU enter sleep but this action causes the PA9 which is USB detection pin to immediately go high even though there is no USB connection.

Do we allow to manually clear these bits? Is there any suggested method to de-init or shut down the USB properly?

Thanks.

Best regards,
Shirley

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