TM4C1233H6PZIR Datasheet, PDF (316/1233 Pages) Texas Instruments – Tiva TM4C1233H6PZ Microcontroller

System Control
Register 50: Universal Serial Bus Software Reset (SRUSB), offset 0x528
The SRUSB register provides software the capability to reset the available USB module. This register
provides the same capability as the legacy Software Reset Control n SRCRn registers specifically
for the USB module and has the same bit polarity as the corresponding SRCRn bits.
A peripheral is reset by software using a simple two-step process:
1. Software sets a bit (or bits) in the SRUSB register. While the SRUSB bit is 1, the peripheral is
held in reset.
2. Software completes the reset process by clearing the SRUSB bit.
There may be latency from the clearing of the SRUSB bit to when the peripheral is ready for use.
Software can check the corresponding PRUSB bit to be sure.
Important: This register should be used to reset the USB module. To support legacy software, the
SRCR2 register is available. Setting the USB0 bit in the SRCR2 register also resets the
USB module. If the USB0 bit is set by writing to the SRCR2 register, it can be read back
correctly when reading the SRCR2 register. If software uses this register to reset the
USB module, the write causes proper operation, but the value of the USB0 bit is not
reflected in the SRCR2 register. If software uses both legacy and peripheral-specific
register accesses, the peripheral-specific registers must be accessed by
read-modify-write operations that affect only peripherals that are not present in the
legacy registers. In this manner, both the peripheral-specific and legacy registers have
coherent information.
Universal Serial Bus Software Reset (SRUSB)
Base 0x400F.E000
Offset 0x528
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
R0
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
R/W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit/Field
31:1
0
Name
reserved
R0
Type
RO
R/W
Reset
0
0
Description
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.
USB Module Software Reset
Value Description
1 USB module is reset.
0 USB module is not reset.
316
July 17, 2013
Texas Instruments-Production Data