Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Data Sheet

 809

SAM9M10 [DATASHEET]

6355F–ATARM–12-Mar-13

Self powered devices can detect 5V VBUS using a PIO. When the device is not connected to a host, device power
consumption can be reduced by the DETACH bit in UDPHS_CTRL. Disabling the transceiver is automatically done.
HSDM, HSDP, FSDP and FSDP lines are tied to GND pull-downs integrated in the hub downstream ports.

When no device is connected, the USB FSDP and FSDM signals are tied to GND by 15 K

Ω pull-downs integrated

in the hub downstream ports. When a device is attached to an hub downstream port, the device connects a 1.5 K

Ω

pull-up on FSDP. The USB bus line goes into IDLE state, FSDP is pulled-up by the device 1.5 K

Ω resistor to 3.3V

and FSDM is pulled-down by the 15 K

Ω resistor to GND of the host.

After pull-up connection, the device enters the powered state. The transceiver remains disabled until bus activity is
detected.

In case of low power consumption need, the device can be stopped. When the device detects the VBUS, the soft-
ware must enable the USB transceiver by enabling the EN_UDPHS bit in UDPHS_CTRL register.

The software can detach the pull-up by setting DETACH bit in UDPHS_CTRL register.

After its connection to a USB host, the USB device waits for an end-of-bus reset. The unmasked flag ENDRESET
is set in the UDPHS_IEN register and an interrupt is triggered.

Once the ENDRESET interrupt has been triggered, the device enters Default State. In this state, the UDPHS soft-
ware must:

• Enable the default endpoint, setting the EPT_ENABL flag in the UDPHS_EPTCTLENB[0] register and, 

optionally, enabling the interrupt for endpoint 0 by writing 1 in EPT_0 of the UDPHS_IEN register. The 
enumeration then begins by a control transfer.

• Configure the Interrupt Mask Register which has been reset by the USB reset detection

• Enable the transceiver.

In this state, the EN_UDPHS bit in UDPHS_CTRL register must be enabled.

After a Set Address standard device request, the USB host peripheral enters the address state.

: before the device enters address state, it must achieve the Status IN transaction of the control transfer,

i.e., the UDPHS device sets its new address once the TX_COMPLT flag in the UDPHS_EPTCTL[0] register has
been received and cleared.

To move to address state, the driver software sets the DEV_ADDR field and the FADDR_EN flag in the
UDPHS_CTRL register.

Once a valid Set Configuration standard request has been received and acknowledged, the device enables end-
points corresponding to the current configuration. This is done by setting the BK_NUMBER, EPT_TYPE, EPT_DIR
and EPT_SIZE fields in the UDPHS_EPTCFGx registers and enabling them by setting the EPT_ENABL flag in the
UDPHS_EPTCTLENBx registers, and, optionally, enabling corresponding interrupts in the UDPHS_IEN register.

When a Suspend (no bus activity on the USB bus) is detected, the DET_SUSPD signal in the UDPHS_STA regis-
ter is set. This triggers an interrupt if the corresponding bit is set in the UDPHS_IEN register. This flag is cleared by
writing to the UDPHS_CLRINT register. Then the device enters Suspend Mode.