USB Device Controller
1570
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Universal Serial Bus (USB)
29.3.1.7 System Configuration Register 1 (SYSCON1)
This read/write register provides control functions for power management and miscellaneous control for
the core.
Values depend on whether the reset action comes from the USB device controller (CPU) or the USB host.
Figure 29-34. System Configuration Register 1 (SYSCON1) [address = FCF78A0Ch]
15
9
8
Reserved
CFG_LOCK
R-0
R/W-0
7
6
5
4
3
2
1
0
DATA_ENDIAN
DMA_ENDIAN
Reserved
NAK_EN
AUTODEC_DIS
SELF_PWR
SOFF_DIS
PULLUP_EN
R/W-0
R/W-0
R-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value at reset
Table 29-37. System Configuration Register 1 (SYSCON1) Field Descriptions
Bit
Field
Value
Description
15-9
Reserved
0
Reserved
8
CFG_LOCK
Device configuration locked bit: after the USB device controller has entered the device configuration
(registers 0x20 to 0x3F), it must set the CFG_LOCK bit so that the device can be used. When the
device configuration is not locked, the device is not ready to be used.
0
Device configuration is not locked. Device is not ready
1
Device configuration is locked.
The value after the USB device controller hardware reset is low; after USB reset, it is unchanged
(keep previous configuration).
7
DATA_ENDIAN
The data endian bit can be set by the USB device controller to select little- or big-endian format on
data access (read or write). See
.
0
Little endian
1
Big endian
The value after USB device controller hardware reset is low; after USB reset, it is unchanged (keep
previous configuration).
6
DMA_ENDIAN
The DMA data endian bit can be set by the USB device controller to select little- or big-endian
format on data access (read or write). See
0
Little endian
1
Big endian
The value after USB device controller hardware reset is low; after USB reset, it is unchanged (keep
previous configuration).
5
Reserved
0
Reserved
4
NAK_EN
The NAK enable bit can be set by the USB device controller to be signaled for NAK transaction
handshake response. When this bit is set, STAT_FLG.NAK is set on a NAK handshake if no non-
handled interrupt is pending on the endpoint, and the endpoint interrupt is asserted. In the normal
mode, when cleared, NAK handshake response to the USB host is made transparent to the USB
device controller and no interrupt is asserted.
0
NAK is disabled.
1
NAK is enabled.
The value after system reset or USB reset is low.
Note: If the USB device controller sets this bit, it must wait for a NAK interrupt before
selecting TX endpoint to write TX data.
3
AUTODEC_DIS
The autodecode process disabled can be set to force software to handle all EP0 transactions
(except the SET_ADDRESS transaction).
0
Autodecode process is activated (see
1
Autodecode process is deactivated. The value after USB device controller hardware reset is low;
after USB reset, it is unchanged.