LM3S9B81 Datasheet, PDF (992/1155 Pages) Texas Instruments – Stellaris® LM3S9B81 Microcontroller

Universal Serial Bus (USB) Controller
OTG A /
Host
OTG B /
Device
Register 324: USB General-Purpose Control and Status (USBGPCS), offset
0x41C
USBGPCS provides the state of the internal ID signal.
Note:
When used in OTG mode, USB0VBUS and USB0ID do not require any configuration as they
are dedicated pins for the USB controller and directly connect to the USB connector's VBUS
and ID signals. If the USB controller is used as either a dedicated Host or Device, the
DEVMODOTG and DEVMOD bits in the USB General-Purpose Control and Status
(USBGPCS) register can be used to connect the USB0VBUS and USB0ID inputs to fixed
levels internally, freeing the PB0 and PB1 pins for GPIO use. For proper self-powered Device
operation, the VBUS value must still be monitored to assure that if the Host removes VBUS,
the self-powered Device disables the D+/D- pull-up resistors. This function can be
accomplished by connecting a standard GPIO to VBUS.
USB General-Purpose Control and Status (USBGPCS)
Base 0x4005.0000
Offset 0x41C
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
reserved
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
reserved
DEVMODOTG DEVMOD
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
R/W
R/W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit/Field
31:2
1
Name
reserved
DEVMODOTG
Type
Reset Description
RO 0x0000.000 Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
R/W
0
Enable Device Mode
This bit enables the DEVMOD bit to control the state of the internal ID
signal in OTG mode.
Value Description
0 The mode is specified by the state of the internal ID signal.
1 This bit enables the DEVMOD bit to control the internal ID signal.
0
DEVMOD
R/W
0
Device Mode
This bit specifies the state of the internal ID signal in Host mode and in
OTG mode when the DEVMODOTG bit is set.
In Device mode this bit is ignored (assumed set).
Value Description
0 Host mode
1 Device mode
992
June 29, 2010
Texas Instruments-Advance Information