USB Registers
1781
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Universal Serial Bus (USB) Controller
27.5.65 USBEPC Register (Offset = 0x400) [reset = 0x0]
USB External Power Control (USBEPC)
OTG A / Host
OTG B / Device
This 32-bit register specifies the function of the two-pin external power interface (USB0EPEN and
USB0PFLT). The assertion of the power fault input may generate an automatic action, as controlled by the
hardware configuration registers. The automatic action is necessary because the fault condition may
require a response faster than one provided by firmware.
USBEPC is shown in
and described in
Return to
Figure 27-78. USBEPC Register
31
30
29
28
27
26
25
24
RESERVED
R-0x0
23
22
21
20
19
18
17
16
RESERVED
R-0x0
15
14
13
12
11
10
9
8
RESERVED
PFLTACT
R-0x0
R/W-0x0
7
6
5
4
3
2
1
0
RESERVED
PFLTAEN
PFLTSEN
PFLTEN
RESERVED
EPENDE
EPEN
R-0x0
R/W-0x0
R/W-0x0
R/W-0x0
R-0x0
R/W-0x0
R/W-0x0
Table 27-85. USBEPC Register Field Descriptions
Bit
Field
Type
Reset
Description
31-10
RESERVED
R
0x0
9-8
PFLTACT
R/W
0x0
Power Fault Action.
This bit field specifies how the USB0EPEN signal is changed when
detecting a USB power fault.
0x0 = Unchanged. USB0EPEN is controlled by the combination of
the EPEN and EPENDE bits.
0x1 = Tristate. USB0EPEN is undriven (tristate).
0x2 = Low. USB0EPEN is driven Low.
0x3 = High. USB0EPEN is driven High.
7
RESERVED
R
0x0
6
PFLTAEN
R/W
0x0
Power Fault Action Enable.
This bit specifies whether a USB power fault triggers any automatic
corrective action regarding the driven state of the USB0EPEN signal.
0x0 = Disabled. USB0EPEN is controlled by the combination of the
EPEN and EPENDE bits.
0x1 = Enabled. The USB0EPEN output is automatically changed to
the state specified by the PFLTACT field.
5
PFLTSEN
R/W
0x0
Power Fault Sense.
This bit specifies the logical sense of the USB0PFLT input signal
that indicates an error condition.
The complementary state is the inactive state.
0x0 = Low Fault. If USB0PFLT is driven Low, the power fault is
signaled internally (if enabled by the PFLTEN bit).
0x1 = High Fault. If USB0PFLT is driven High, the power fault is
signaled internally (if enabled by the PFLTEN bit).