LM3S8738 Datasheet, PDF (171/616 Pages) List of Unclassifed Manufacturers – Microcontroller

Stellaris® LM3S8738 Microcontroller
Register 10: User Debug (USER_DBG), offset 0x1D0
Note: Offset is relative to System Control base address of 0x400FE000.
This register provides a write-once mechanism to disable external debugger access to the device
in addition to 27 additional bits of user-defined data. The DBG0 bit (bit 0) is set to 0 from the factory
and the DBG1 bit (bit 1) is set to 1, which enables external debuggers. Changing the DBG1 bit to
0 disables any external debugger access to the device permanently, starting with the next power-up
cycle of the device. The NW bit (bit 31) indicates that the register has not yet been committed and
is controlled through hardware to ensure that the register is only committed once. Prior to being
committed, bits can only be changed from 1 to 0. The reset value shown only applies to power-on
reset; any other type of reset does not affect this register. Once committed, this register cannot be
restored to the factory default value.
User Debug (USER_DBG)
Base 0x400F.E000
Offset 0x1D0
Type R/W, reset 0xFFFF.FFFE
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
NW
DATA
Type R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DATA
DBG1 DBG0
Type R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
Bit/Field
31
30:2
1
0
Name
NW
DATA
DBG1
DBG0
Type
Reset Description
R/W
1
User Debug Not Written
When set, this bit indicates that this 32-bit register has not been
committed. When clear, this bit specifies that this register has been
committed and may not be committed again.
R/W 0x1FFFFFFF User Data
Contains the user data value. This field is initialized to all 1s and can
only be committed once.
R/W
1
Debug Control 1
The DBG1 bit must be 1 and DBG0 must be 0 for debug to be available.
R/W
0
Debug Control 0
The DBG1 bit must be 1 and DBG0 must be 0 for debug to be available.
June 22, 2010
171
Texas Instruments-Production Data