USB Device Controller
1572
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Universal Serial Bus (USB)
29.3.1.8 System Configuration Register 2 (SYSCON2)
This set-only register provides miscellaneous controls for the function. A read to this register always
returns 0.
Figure 29-35. System Configuration Register 2 (SYSCON2) [address = FCF78A0Eh]
15
8
Reserved
R-0
7
6
5
4
3
2
1
0
Reserved
RMT_WKP
STALL_CMD
Reserved
DEV_CFG
CLR_CFG
Reserved
R-0
W-0
W-0
R-0
W-0
W-0
R-0
LEGEND: R = Read only; W = Write only; -
n
= value at reset
Table 29-39. System Configuration Register 2 (SYSCON2) Field Descriptions
Bit
Field
Value
Description
15-7
Reserved
0
Reserved
6
RMT_WKP
The set-only remote wake-up bit, when written with a 1, initiates the remote wake-up sequence
even if DEVSTAT.R_WK_OK bit was not previously set to 1 by the USB host. Reading this bit
always returns 0. Writing 0 into this bit has no effect. To generate a resume, the software must
check the remote wake-up enable value before initiating any wake-up sequence.
0
No action.
1
Initiates the remote wake-up sequence.
Always read 0.
5
STALL_CMD
The set-only stall command bit only concerns non-autodecoded requests on control endpoint (EP0).
This is asserted in response to a USB command where either the command itself or its data is
invalid. Asserting this bit forces the non-autodecoded command to complete with a STALL
handshake. It has no effect for autodecoded requests.
0
No action.
1
Stall current USB command.
Always read 0.
4
Reserved
0
Reserved
3
DEV_CFG
If the USB device controller receives a SET_CONFIGURATION with a valid configuration value,
and the device is in addressed state, it must write a 1 to the device configured (DEV_CFG) bit to
inform the command decode that the device moves to configured state. The core sets the
DEVSTAT.CFG bit to 1. If the device is already configured when the SET_CONFIGURATION
request is received, the USB device controller does not have to set this bit. If the new configuration
value is 0, USB device controller must set the SYSCON2.CLR_CFG bit to move to addressed state.
Reading this bit always returns 0. Writing 0 into this bit has no effect.
0
No action.
1
Allows DEVSTAT.CFG to be set.
Always read 0.
2
CLR_CFG
If the USB device controller receives a SET_CONFIGURATION with a configuration value of 0, and
if the device is configured, it must write a 1 to the clear configured (CLR_CFG) bit to inform the
command decode that the device becomes deconfigured (moves to addressed state). The core
clears the DEVSTAT.CFG bit. Reading this bit always returns 0. Writing 0 into this bit has no effect.
0
No action.
1
Allows DEVSTAT.CFG to be cleared.
Always read 0.
1-0
Reserved
0
Reserved