USB Device Controller (UDC) - Workflow

Common workflow for all USB devices.

1. Ensure that conf_usb.h is available and contains the following configuration which is the main USB device configuration:

   • // Vendor ID provided by USB org (ATMEL 0x03EB)
     #define USB_DEVICE_VENDOR_ID 0x03EB // Type Word
     // Product ID (Atmel PID referenced in usb_atmel.h)
     #define USB_DEVICE_PRODUCT_ID 0xXXXX // Type Word
     // Major version of the device
     #define USB_DEVICE_MAJOR_VERSION 1 // Type Byte
     // Minor version of the device
     #define USB_DEVICE_MINOR_VERSION 0 // Type Byte
     // Maximum device power (mA)
     #define USB_DEVICE_POWER 100 // Type 9-bits
     // USB attributes to enable features
     #define USB_DEVICE_ATTR USB_CONFIG_ATTR_BUS_POWERED // Flags 

2. Call the USB device stack start function to enable stack and start USB:

   • udc_start(); 

     Note

     In case of USB dual roles (Device and Host) managed through USB OTG connector (USB ID pin), the call of udc_start() must be removed and replaced by uhc_start(). SeRefer to "AVR4950 section 6.1 Dual roles" for further information about dual roles.