AT90USB646 datasheet(258/459 Pages) ATMEL

258 / 459 page

258

7593H–AVR–11/08

ATmega32U6/AT90USB64/128

both Pipe/Endpoint 4 and 5 use a common area. The data of those endpoints are potentially

lost.

Note that:

• the data of Pipe/Endpoint 0 are never lost whatever the activation or deactivation of the

higher Pipe/Endpoint. Its data is lost if it is deactivated.

• Deactivate and reactivate the same Pipe/Endpoint with the same parameters does not lead

to a “slide” of the higher endpoints. For those endpoints, the data are preserved.

• CFGOK is set by hardware even in the case where there is a “conflict” in the memory

allocation.

21.8

PAD suspend

The next figures illustrates the pad behaviour:

• In the “idle” mode, the pad is put in low power consumption mode.

• In the “active” mode, the pad is working.

Figure 21-15. 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.

Idle mode

Active mode

USBE=1

& DETACH=0

& suspend

USBE=0

| DETACH=1

| suspend

SUSPI

Suspend detected = USB pad power down

Clear Suspend by software

Resume = USB pad wake-up

Clear Resume by software

WAKEUPI

PAD status

Active

Power Down

Active

AT90USB646 Datasheet(PDF) 258 Page - ATMEL Corporation