USB Software Operating modes

Depending on the USB operating mode, the software should perform some the following operations:

Power On the USB interface

•Configure PLL interface

•Enable PLL

•Check PLL lock

•Enable USB interface

•Configure USB interface (USB Endpoint 0 configuration)

•Attach USB device

Power Off the USB interface

•Detach USB device

•Disable USB interface

•Disable PLL

Suspending the USB interface

•Clear Suspend Bit

•Set USB suspend clock

•Disable PLL

•Be sure to have interrupts enabled (WAKEUPE) to exit sleep mode

•Put the MCU in sleep mode

Resuming the USB interface

•Enable PLL

•Wait PLL lock

•Clear USB suspend clock

•Clear Resume information

191

7707A–AVR–01/07