SAM3A8C Atmel Corporation, SAM3A8C Datasheet - Page 1080

• Manufacturer Part Number: SAM3A8C
• Manufacturer: Atmel Corporation

39.5.1.10
1080
1080
SAM3X/A
SAM3X/A
ID Detection
The control logic of the VBUS pad outputs two signals:
In device mode, the UOTGHS_SR.VBUS bit follows the Session_valid comparator output:
In host mode, the UOTGHS_SR.VBUS bit follows an hysteresis based on Session_valid and
Va_Vbus_valid:
The VBus Transition interrupt (UOTGHS_SR.VBUSTI) bit is set on each transition of the
UOTGHS_SR.VBUS bit.
The UOTGHS_SR.VBUS bit is effective whether the UOTGHS is enabled or not.
Figure 39-11 on page 1080
Figure 39-11. ID Detection Input Block Diagram
The USB mode (device or host) can be either detected from the UOTGID pin or software
selected by writing to the UOTGHS_CTRL.UIMOD bit, according to the UOTGHS_CTRL.UIDE
bit. This allows the UOTGID pin to be used as a general purpose I/O pin even when the USB
interface is enabled.
By default, the UOTGID pin is selected (UOTGHS_CTRL.UIDE is written to one) and the UOT-
GHS is in device mode (UOTGHS_SR.ID is one), which corresponds to the case where no Mini-
A plug is connected, i.e. no plug or a Mini-B plug is connected and the UOTGID pin is kept high
by the internal pull-up resistor from the I/O Controller (which must be enabled if UOTGID is
used).
The ID Transition Interrupt (UOTGHS_SR.IDTI) bit is set on each transition of the
UOTGHS_SR.ID bit, i.e. when a Mini-A plug (host mode) is connected or disconnected. This
does not occur when a Mini-B plug (device mode) is connected or disconnected.
• The Session_valid signal is high when the voltage on the VBUS pad is higher than or equal to
• The Va_Vbus_valid signal is high when the voltage on the VBUS pad is higher than or equal
• It is set when the voltage on the VBUS pad is higher than or equal to 1.4V.
• It is cleared when the voltage on the VBUS pad is lower than 1.4V.
• It is set when the voltage on the VBUS pad is higher than or equal to 4.4V.
• It is cleared when the voltage on the VBUS pad is lower than 1.4V.
1.4V.
to 4.4V.
USB_ID
I/O Controller
VDD
shows how the ID transitions are detected.
UOTGHS_CTRL
UIMOD
UOTGHS_CTRL
1
0
UIDE
UOTGHS_SR
ID
11057A–ATARM–17-Feb-12
11057A–ATARM–17-Feb-12
UOTGHS_SR
IDTI