Datasheet

1063
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
Figure 39-8. Pad Behavior
 In the Idle state, the pad is put in low-power consumption mode, i.e., the differential receiver of the USB pad
is off, and internal pull-downs with strong value (15 K) are set in both DP/DM to avoid floating lines.
 In the Active state, the pad is working.
Figure 39-9 on page 1063 illustrates the pad events leading to a PAD state change.
Figure 39-9. Pad Events
The UOTGHS_DEVISR.SUSP bit is set and the Wake-Up Interrupt (UOTGHS_DEVISR.WAKEUP) bit is cleared
when a USB “Suspend” state has been detected on the USB bus. This event automatically puts the USB pad in
Idle state. The detection of a non-idle event sets UOTGHS_DEVISR.WAKEUP, clears UOTGHS_DEVISR.SUSP
and wakes up the USB pad.
The pad goes to the Idle state if the macro is disabled or if the UOTGHS_DEVCTRL.DETACH bit is written to one.
It returns to the Active state when UOTGHS_CTRL.USBE is written to one and UOTGHS_DEVCTRL.DETACH is
written to zero.
Idle
Active
UOTGHS_CTRL.USBE = 1
& UOTGHS_DEVCTRL.DETACH = 0
& Suspend
UOTGHS_CTRL.USBE = 0
| UOTGHS_DEVCTRL.DETACH = 1
| Suspend
UOTGHS_DEVISR.SUSP
pu-ekaw no deraelCdetceted dnepsuS
Wake-up detected Cleared by software to acknowledge the interrupt
UOTGHS_DEVISR.WAKEUP
PAD State
Active
Idle
Active