78 otg device control register (devctl), Section 4.78 – Texas Instruments TMS320DM357 User Manual
Page 137
4.78 OTG Device Control Register (DEVCTL)
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Registers
The OTG Device Control Register (DEVCTL) is shown in
and described in
.
Figure 93. OTG Device Control Register (DEVCTL)
7
6
5
4
3
2
1
0
BDEVICE
FSDEV
LSDEV
VBUS
HOSTMODE
HOSTREQ
SESSION
R-0
R-0
R-0
R-0
R-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 94. OTG Device Control Register (DEVCTL) Field Descriptions
Bit
Field
Value
Description
7
BDEVICE
This read-only bit indicates whether the USB controller is operating as the 'A' device or the 'B'
device.
0
'A' device
1
'B' device
Only valid while a session is in progress.
6
FSDEV
0-1
This read-only bit is set when a full-speed or high-speed device has been detected being connected
to the port (high-speed devices are distinguished from full-speed by checking for high-speed chirps
when the device is reset). Only valid in Host mode.
5
LSDEV
0-1
This read-only bit is set when a low-speed device has been detected being connected to the port.
Only valid in Host mode.
4-3
VBUS
0-3h
These read-only bits encode the current VBus level as follows:
0
Below Session End
1h
Above Session End, below AValid
2h
Above AValid, below VBusValid
3h
Above VBusValid
2
HOSTMODE
0-1
This read-only bit is set when the USB controller is acting as a Host.
1
HOSTREQ
0-1
When set, the USB controller will initiate the Host Negotiation when Suspend mode is entered. It is
cleared when Host Negotiation is completed. ('B' device only)
0
SESSION
0-1
When operating as an 'A' device, you must set or clear this bit start or end a session. When
operating as a 'B' device, this bit is set/cleared by the USB controller when a session starts/ends.
You must also set this bit to initiate the Session Request Protocol. When the USB controller is in
Suspend mode, you may clear the bit to perform a software disconnect.
A special software routine is required to perform SRP. Details will be made available in a later
document version.
SPRUGH3 – November 2008
Universal Serial Bus (USB) Controller
137