Datasheet

SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1064
39.5.1.8 Customizing of OTG Timers
It is possible to refine some OTG timers thanks to the Timer Page (UOTGHS_CTRL.TIMPAGE) and Timer Value
(UOTGHS_CTRL.TIMVALUE) fields, as shown in Table 39-4 on page 1064.
Note: 1. “On-The-Go Supplement to the USB 2.0 Specification Revision 1.0a”.
UOTGHS_CTRL.TIMPAGE is used to select the OTG timer to access while UOTGHS_CTRL.TIMVALUE indicates
the time-out value of the selected timer.
UOTGHS_CTRL.TIMPAGE and UOTGHS_CTRL.TIMVALUE can be read or written. Before writing them, the user
shall unlock write accesses by writing a one to the Timer Access Unlock (UOTGHS_CTRL.UNLOCK) bit. This is
not required for read accesses, except before accessing UOTGHS_CTRL.TIMPAGE if it has to be written in order
to read the UOTGHS_CTRL.TIMVALUE field of another OTG timer.
39.5.1.9 Plug-In Detection
The USB connection is detected from the VBUS pad. Figure 39-10 on page 1064 shows the architecture of the
plug-in detector.
Figure 39-10. Plug-In Detection Input Block Diagram
The control logic of the VBUS pad outputs two signals:
 The Session_valid signal is high when the voltage on the VBUS pad is higher than or equal to 1.4V.
 The Va_Vbus_valid signal is high when the voltage on the VBUS pad is higher than or equal to 4.4V.
In device mode, the UOTGHS_SR.VBUS bit follows the Session_valid comparator output:
 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.
Table 39-4. Customizing of OTG Timers
TIMPAGE
0b00
AWaitVrise Time-Out
(see OTG Standard
(1)
Section 6.6.5.1)
0b01
VbBusPulsing Time-Out
(see OTG Standard
(1)
Section5.3.4)
0b10
PdTmOutCnt Time-Out
(see OTG Standard
(1)
Section 5.3.2)
0b11
SRPDetTmOut Time-Out
(see OTG Standard
(1)
Section 5.3.3)
TIMVALUE
00b 20 ms 15 ms 93 ms 10 µs
01b 50 ms 23 ms 105 ms 100 µs
10b 70 ms 31 ms 118 ms 1 ms
11b 100 ms 40 ms 131 ms 11 ms
VBUSTI
UOTGHS_SR
VBUS
VBUS
UOTGHS_SR
GND
VDD
Pad Logic
Logic
Session_valid
Va_Vbus_valid
R
PU
R
PD
VBus_pulsing
VBus_discharge