USB Device Controller (UDC)

The UDC provides a high-level abstraction of the usb device.

You can use these functions to control the main device state (start/attach/wakeup).

USB Device Custom configuration

The following USB Device configuration must be included in the conf_usb.h file of the application.

USB_DEVICE_VENDOR_ID (Word)
Vendor ID provided by USB org (ATMEL 0x03EB).

USB_DEVICE_PRODUCT_ID (Word)
Product ID (Referenced in usb_atmel.h).

USB_DEVICE_MAJOR_VERSION (Byte)
Major version of the device

USB_DEVICE_MINOR_VERSION (Byte)
Minor version of the device

USB_DEVICE_MANUFACTURE_NAME (string)
ASCII name for the manufacture

USB_DEVICE_PRODUCT_NAME (string)
ASCII name for the product

USB_DEVICE_SERIAL_NAME (string)
ASCII name to enable and set a serial number

USB_DEVICE_POWER (Numeric)
(unit mA) Maximum device power

USB_DEVICE_ATTR (Byte)
USB attributes available:

• USB_CONFIG_ATTR_SELF_POWERED
• USB_CONFIG_ATTR_REMOTE_WAKEUP Note: if remote wake enabled then defines remotewakeup callbacks, see Table 5-2. External API from UDC - Callback

USB_DEVICE_LOW_SPEED (Only defined)
Force the USB Device to run in low speed

USB_DEVICE_HS_SUPPORT (Only defined)
Authorize the USB Device to run in high speed

USB_DEVICE_MAX_EP (Byte)
Define the maximum endpoint number used by the USB Device.
This one is already defined in UDI default configuration. Ex:

• When endpoint control 0x00, endpoint 0x01 and endpoint 0x82 is used then USB_DEVICE_MAX_EP=2
• When only endpoint control 0x00 is used then USB_DEVICE_MAX_EP=0
• When endpoint 0x01 and endpoint 0x81 is used then USB_DEVICE_MAX_EP=1
  (configuration not possible on USBB interface)

Modules
	Implementation of UDC
	Internal implementation.
	USB Device Controller (UDC) - Prerequisites
	Common prerequisites for all USB devices.
	USB Device Controller (UDC) - Example code
	Common example code for all USB devices.
	USB Device Controller (UDC) - Workflow
	Common workflow for all USB devices.
	USB Device Descriptor

Functions
static void	udc_attach (void)
	Attach device to the bus when possible. More...
static void	udc_detach (void)
	Detaches the device from the bus. More...
usb_iface_desc_t UDC_DESC_STORAGE *	udc_get_interface_desc (void)
	Returns a pointer on the current interface descriptor. More...
static bool	udc_include_vbus_monitoring (void)
	Authorizes the VBUS event. More...
static void	udc_remotewakeup (void)
	The USB driver sends a resume signal called "Upstream Resume" This is authorized only when the remote wakeup feature is enabled by host. More...
void	udc_start (void)
	Start the USB Device stack. More...
void	udc_stop (void)
	Stop the USB Device stack. More...

static void udc_attach ( void  )

inlinestatic

Attach device to the bus when possible.

Warning

If a VBus control is included in driver, then it will attach device when an acceptable Vbus level from the host is detected.

References udd_attach().

static void udc_detach ( void  )

inlinestatic

Detaches the device from the bus.

The driver must remove pull-up on USB line D- or D+.

References udd_detach().

usb_iface_desc_t UDC_DESC_STORAGE* udc_get_interface_desc

(

void

)

Returns a pointer on the current interface descriptor.

Returns

pointer on the current interface descriptor.

References udc_ptr_iface.

static bool udc_include_vbus_monitoring ( void  )

inlinestatic

Authorizes the VBUS event.

Returns

true, if the VBUS monitoring is possible.

VBus monitoring used cases

The VBus monitoring is used only for USB SELF Power application.

• By default the USB device is automatically attached when Vbus is high or when USB is start for devices without internal Vbus monitoring. conf_usb.h file does not contains define USB_DEVICE_ATTACH_AUTO_DISABLE.

  //#define USB_DEVICE_ATTACH_AUTO_DISABLE 

• Add custom VBUS monitoring. conf_usb.h file contains define USB_DEVICE_ATTACH_AUTO_DISABLE:

  #define USB_DEVICE_ATTACH_AUTO_DISABLE 

  User C file contains:

  // Authorize VBUS monitoring
  if (!udc_include_vbus_monitoring()) {
    // Implement custom VBUS monitoring via GPIO or other
  }
  Event_VBUS_present() // VBUS interrupt or GPIO interrupt or other
  {
    // Attach USB Device
    udc_attach();
  }

• Case of battery charging. conf_usb.h file contains define USB_DEVICE_ATTACH_AUTO_DISABLE:

  #define USB_DEVICE_ATTACH_AUTO_DISABLE 

  User C file contains:

  Event VBUS present() // VBUS interrupt or GPIO interrupt or ..
  {
    // Authorize battery charging, but wait key press to start USB.
  }
  Event Key press()
  {
    // Stop batteries charging
    // Start USB
    udc_attach();
  }

References udd_include_vbus_monitoring().

static void udc_remotewakeup ( void  )

inlinestatic

The USB driver sends a resume signal called "Upstream Resume" This is authorized only when the remote wakeup feature is enabled by host.

References udd_send_remotewakeup().

void udc_start

(

void

)

Start the USB Device stack.

References udd_enable().

Referenced by main().

void udc_stop

(

void

)

Stop the USB Device stack.

References udc_reset(), and udd_disable().