Datasheet

SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1068
See Section 39.5.1.6 for more details about DPRAM management.
39.5.2.6 Address Setup
The USB device address is set up according to the USB protocol.
 After all kinds of resets, the USB device address is 0.
 The host starts a SETUP transaction with a SET_ADDRESS (addr) request.
 The user writes this address to the USB Address (UOTGHS_DEVCTRL.UADD) field, and writes a zero to
the Address Enable (UOTGHS_DEVCTRL.ADDEN) bit, so the actual address is still 0.
 The user sends a zero-length IN packet from the control endpoint.
 The user enables the recorded USB device address by writing a one to UOTGHS_DEVCTRL.ADDEN.
Once the USB device address is configured, the controller filters the packets to only accept those targeting the
address stored in UOTGHS_DEVCTRL.UADD.
UOTGHS_DEVCTRL.UADD and UOTGHS_DEVCTRL.ADDEN shall not be written all at once.
UOTGHS_DEVCTRL.UADD and UOTGHS_DEVCTRL.ADDEN are cleared:
 on a hardware reset,
 when the UOTGHS is disabled (UOTGHS_CTRL.USBE written to zero),
 when a USB reset is detected.
When UOTGHS_DEVCTRL.UADD or UOTGHS_DEVCTRL.ADDEN is cleared, the default device address 0 is
used.
39.5.2.7 Suspend and Wake-up
When an idle USB bus state has been detected for 3 ms, the controller sets the Suspend
(UOTGHS_DEVISR.SUSP) interrupt bit. The user may then write a one to the UOTGHS_CTRL.FRZCLK bit to
reduce the power consumption.
To recover from the Suspend mode, the user shall wait for the Wake-Up (UOTGHS_DEVISR.WAKEUP) interrupt
bit, which is set when a non-idle event is detected, then write a zero to UOTGHS_CTRL.FRZCLK.
As the UOTGHS_DEVISR.WAKEUP interrupt bit is set when a non-idle event is detected, it can occur whether the
controller is in the Suspend mode or not. The UOTGHS_DEVISR.SUSP and UOTGHS_DEVISR.WAKEUP
interrupts are thus independent, except that one bit is cleared when the other is set.
39.5.2.8 Detach
The reset value of the UOTGHS_DEVCTRL.DETACH bit is one.
It is possible to initiate a device re-enumeration by simply writing a one then a zero to
UOTGHS_DEVCTRL.DETACH.
UOTGHS_DEVCTRL.DETACH acts on the pull-up connections of the D+ and D- pads. See “Device mode” for
further details.
39.5.2.9 Remote Wake-up
The Remote Wake-Up request (also known as Upstream Resume) is the only one the device may send on its own
initiative, but the device should have beforehand been allowed to by a DEVICE_REMOTE_WAKEUP request from
the host.
 First, the UOTGHS must have detected a “Suspend” state on the bus, i.e. the Remote Wake-Up request can
only be sent after a UOTGHS_DEVISR.SUSP interrupt has been set.
 The user may then write a one to the Remote Wake-Up (UOTGHS_DEVCTRL.RMWKUP) bit to send an
upstream resume to the host for a remote wake-up. This will automatically be done by the controller after
5ms of inactivity on the USB bus.