Datasheet

191
7799D–AVR–11/10
ATmega8U2/16U2/32U2
Figure 20-10. USB Endpoint Interrupt vector sources
Each endpoint has 8 interrupts sources associated with flags, and each source can be enabled
to trigger the corresponding endpoint interrupt.
If, for an endpoint, at least one of the sources is enabled to trigger interrupt, the corresponding
event(s) will make the program branch to the USB Endpoint Interrupt vector. The user may
determine the source (endpoint) of the interrupt by reading the “UDINT – USB Device Interrupt
Register” on page 210.
20.5 Power modes
20.5.1 Idle mode
In Idle mode, the CPU is halted (CPU clock stopped). The Idle mode is taken wether the USB
controller is running or not. The CPU can wake up on any USB interrupts.
20.5.2 Power-down
In Power-down mode, the oscillator is stopped and halts all the clocks (CPU and peripherals).
The USB controller wakes up when:
• the WAKEUPI interrupt is triggered (single asynchronous interrupt)
FLERRE
UEIENX.7
OVERFI
UESTAX.6
UNDERFI
UESTAX.5
NAKINI
UEINTX.6
NAKINE
UEIENX.6
NAKOUTI
UEINTX.4
TXSTPE
UEIENX.4
RXSTPI
UEINTX.3
TXOUTE
UEIENX.3
RXOUTI
UEINTX.2
RXOUTE
UEIENX.2
STALLEDI
UEINTX.1
STALLEDE
UEIENX.1
EPINT
UEINT.X
Endpoint 0
Endpoint 1
Endpoint 2
Endpoint 3
Endpoint 4
TXINI
UEINTX.0
TXINE
UEIENX.0
USB Endpoi
Interrupt Ve
c