The external UDC API allows the application to manage common USB device behavior and receive common USB device events. These controls and events are common to any USB application.
Figure 1. External API from UDC
| Declaration | Description |
|---|---|
| udc_start() | Start USB device stack |
| udc_stop() | Stop USB device stack |
|
udc_attach() udc_detach() |
Authorize the device enumeration or not. Enable pull-up on DM or DP. |
| udc_remotewakeup() | Wake-up the USB device |
All UDC callbacks are optional and defined by user in usb_conf.h for each application. When defined, the callbacks will be called by the UDD ISR.
| Define name | Description |
|---|---|
| UDC_VBUS_EVENT(bool b_present) | To notify VBUS level change (only if USB hardware includes VBUS monitoring) |
| UDC_SUSPEND_EVENT() | Called when USB enters in Suspend mode |
| UDC_RESUME_EVENT() | Called when USB wakes-up |
| UDC_SOF_EVENT() | Called for each received SOF each 1ms Note: Available in High and Full Speed mode |
| UDC_REMOTEWAKEUP_ENABLE() | Called when USB host requests to enable/disable remote wake-up feature when the device supports it |
| UDC_REMOTEWAKEUP_DISABLE() | |
| UDC_GET_EXTRA_STRING() | When an extra string descriptor must be supported (other than manufacturer, a product and serial string) |
| UDC_SPECIFIC_REQUEST() | When a specific device setup request must be supported |