atmega32u4-16mu ATMEL Corporation, atmega32u4-16mu Datasheet - Page 281

• Manufacturer Part Number: atmega32u4-16mu
• Description: Atmega32u4 8-bit Avr Microcontroller With 32k Bytes Of Isp Flash And Usb Controller
• Manufacturer: ATMEL Corporation

22.9
7766A–AVR–03/08
Plug-in detection
Figure 22-12. Pad behaviour
The SUSPI flag indicated that a suspend state has been detected on the USB bus. This flag
automatically put the USB pad in Idle. The detection of a non-idle event sets the WAKEUPI flag
and wakes-up the USB pad.
Moreover, the pad can also be put in the “idle” mode if the DETACH bit is set. It come back in
the active mode when the DETACH bit is cleared.
The USB connection is detected by the VBUS pad, thanks to the following architecture:
SUSPI
WAKEUPI
PAD status
Active
Suspend detected = USB pad power down
Idle mode
Resume = USB pad wake-up
| DETACH=1
| suspend
USBE=0
Power Down
& DETACH=0
& suspend
USBE=1
Clear Suspend by software
Clear Resume by software
Active mode
Active
ATmega32U4
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