Register Descriptions
1301
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
M3 Universal Serial Bus (USB) Controller
18.5.2 USB Power Management Register (USBPOWER), offset 0x001
The power management 8-bit register (USBPOWER) is used for controlling SUSPEND and RESUME
signaling, and some basic operational aspects of the USB controller.
Mode(s):
OTG A or Host
OTG B or Device
USBPOWER in OTG A/Host Mode is shown in
and described in
Figure 18-3. Power Management Register (USBPOWER) in OTG A/Host Mode
7
4
3
2
1
0
Reserved
RESET
RESUME
SUSPEND
PWRDNPHY
R-0
R/W-0
R/W-0
R/W-1S
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 18-6. Power Management Register (USBPOWER) in OTG A/Host Mode Field Descriptions
Bit
Field
Value
Description
7-4
Reserved
0
Reserved
3
RESET
RESET signaling.
0
Ends RESET signaling on the bus.
1
Enables RESET signaling on the bus.
2
RESUME
RESUME signaling. The bit should be cleared by software 20 ms after being set.
0
Ends RESUME signaling on the bus.
1
Enables RESUME signaling when the Device is in SUSPEND mode.
1
SUSPEND
SUSPEND mode
0
No effect
1
Enables SUSPEND mode.
0
PWRDNPHY
Power Down PHY
0
No effect
1
Powers down the internal USB PHY.
USBPOWER in OTG B/Device Mode is shown in
and described in
Figure 18-4. Power Management Register (USBPOWER) in OTG B/Device Mode
7
6
5
4
3
2
1
0
ISOUPDATE
SOFTCONN
Reserved
RESET
RESUME
SUSPEND
PWRDNPHY
R/W-0
R/W-0
R-0
R/W-0
R/W-0
R-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 18-7. Power Management Register (USBPOWER) in OTG B/Device Mode Field Descriptions
Bit
Field
Value
Description
7
ISOUPDATE
Isochronous Update
0
No effect
1
The USB controller waits for an SOF token from the time the TXRDY bit is set in the USBTXCSRLn
register before sending the packet. If an IN token is received before an SOF token, then a zero-
length data packet is sent.
6
SOFTCONN
Soft Connect/Disconnect
0
The USB D+/D- lines are tri-stated.
1
The USB D+/D- lines are enabled.
5-4
Reserved
0
Reserved