USB CDC Power request

[PMath.4]

Does the STM USB CDC driver support power negotiation? If so please could someone point me to where I configure a request for more than the default 100mA.

I'm using STM32F407 and CDC is working nicely but the computer only shows that 100mA is requested. I need more than this to power peripherals which will be attached to the uP.

Any help appreciated

[waclawek.jan]

USB devices request current through the bMaxPower field in the standard Configuration descriptor, so simply change it there.

JW

[Peter Mather]

Thanks - took a bit of time to find as the field name misses the "b"

from usbd_cdc.c

__ALIGN_BEGIN uint8_t USBD_CDC_OtherSpeedCfgDesc[USB_CDC_CONFIG_DESC_SIZ] __ALIGN_END =
{
 0x09, /* bLength: Configuation Descriptor size */
 USB_DESC_TYPE_OTHER_SPEED_CONFIGURATION,
 USB_CDC_CONFIG_DESC_SIZ,
 0x00,
 0x02, /* bNumInterfaces: 2 interfaces */
 0x01, /* bConfigurationValue: */
 0x04, /* iConfiguration: */
 0xC0, /* bmAttributes: */
 250, /* MaxPower 500 mA */